diff --git a/.golangci.yml b/.golangci.yml
index 816e2404a9e36..d262ed0e0457b 100644
--- a/.golangci.yml
+++ b/.golangci.yml
@@ -22,6 +22,7 @@ linters:
     - rowserrcheck
     - unconvert
     - makezero
+    - durationcheck
 
 linters-settings:
   staticcheck:
diff --git a/Makefile b/Makefile
index 36291f5d6ca40..3e7fb1f5be216 100644
--- a/Makefile
+++ b/Makefile
@@ -122,7 +122,7 @@ devgotest: failpoint-enable
 gotest: failpoint-enable
 	@echo "Running in native mode."
 	@export log_level=info; export TZ='Asia/Shanghai'; \
-	$(GOTEST) -ldflags '$(TEST_LDFLAGS)' $(EXTRA_TEST_ARGS) -cover $(PACKAGES_TIDB_TESTS) -coverprofile=coverage.txt -check.p true > gotest.log || { $(FAILPOINT_DISABLE); cat 'gotest.log'; exit 1; }
+	$(GOTEST) -ldflags '$(TEST_LDFLAGS)' $(EXTRA_TEST_ARGS) -timeout 20m -cover $(PACKAGES_TIDB_TESTS) -coverprofile=coverage.txt -check.p true > gotest.log || { $(FAILPOINT_DISABLE); cat 'gotest.log'; exit 1; }
 	@$(FAILPOINT_DISABLE)
 
 gotest_in_verify_ci_part_1: failpoint-enable tools/bin/gotestsum tools/bin/gocov tools/bin/gocov-xml
diff --git a/br/pkg/backup/client_test.go b/br/pkg/backup/client_test.go
index e46d832bae3ee..e341f15417f55 100644
--- a/br/pkg/backup/client_test.go
+++ b/br/pkg/backup/client_test.go
@@ -265,7 +265,6 @@ func (r *testBackup) TestSendCreds(c *C) {
 	c.Assert(err, IsNil)
 	opts := &storage.ExternalStorageOptions{
 		SendCredentials: true,
-		SkipCheckPath:   true,
 	}
 	_, err = storage.New(r.ctx, backend, opts)
 	c.Assert(err, IsNil)
@@ -284,7 +283,6 @@ func (r *testBackup) TestSendCreds(c *C) {
 	c.Assert(err, IsNil)
 	opts = &storage.ExternalStorageOptions{
 		SendCredentials: false,
-		SkipCheckPath:   true,
 	}
 	_, err = storage.New(r.ctx, backend, opts)
 	c.Assert(err, IsNil)
diff --git a/br/pkg/conn/conn_test.go b/br/pkg/conn/conn_test.go
index 4de0e96c2f940..256b653898c0d 100644
--- a/br/pkg/conn/conn_test.go
+++ b/br/pkg/conn/conn_test.go
@@ -165,8 +165,6 @@ func TestCheckStoresAlive(t *testing.T) {
 }
 
 func TestGetAllTiKVStores(t *testing.T) {
-	t.Parallel()
-
 	testCases := []struct {
 		stores         []*metapb.Store
 		storeBehavior  StoreBehavior
@@ -258,8 +256,6 @@ func TestGetAllTiKVStores(t *testing.T) {
 }
 
 func TestGetConnOnCanceledContext(t *testing.T) {
-	t.Parallel()
-
 	ctx, cancel := context.WithCancel(context.Background())
 	cancel()
 
diff --git a/br/pkg/kv/checksum_test.go b/br/pkg/kv/checksum_test.go
index 56ef6cfa24f58..8b594f23f698c 100644
--- a/br/pkg/kv/checksum_test.go
+++ b/br/pkg/kv/checksum_test.go
@@ -25,8 +25,6 @@ import (
 func uint64NotEqual(a uint64, b uint64) bool { return a != b }
 
 func TestChecksum(t *testing.T) {
-	t.Parallel()
-
 	checksum := kv.NewKVChecksum(0)
 	require.Equal(t, uint64(0), checksum.Sum())
 
@@ -69,8 +67,6 @@ func TestChecksum(t *testing.T) {
 }
 
 func TestChecksumJSON(t *testing.T) {
-	t.Parallel()
-
 	testStruct := &struct {
 		Checksum kv.Checksum
 	}{
diff --git a/br/pkg/kv/kv_test.go b/br/pkg/kv/kv_test.go
index ab264dd23e9d7..ddf32247e03b2 100644
--- a/br/pkg/kv/kv_test.go
+++ b/br/pkg/kv/kv_test.go
@@ -26,8 +26,6 @@ import (
 )
 
 func TestMarshal(t *testing.T) {
-	t.Parallel()
-
 	dats := make([]types.Datum, 4)
 	dats[0].SetInt64(1)
 	dats[1].SetNull()
@@ -43,8 +41,6 @@ func TestMarshal(t *testing.T) {
 }
 
 func TestSimplePairIter(t *testing.T) {
-	t.Parallel()
-
 	pairs := []Pair{
 		{Key: []byte("1"), Val: []byte("a")},
 		{Key: []byte("2"), Val: []byte("b")},
diff --git a/br/pkg/kv/session_test.go b/br/pkg/kv/session_test.go
index ecb99da864a86..4c3ddf4015f28 100644
--- a/br/pkg/kv/session_test.go
+++ b/br/pkg/kv/session_test.go
@@ -22,8 +22,6 @@ import (
 )
 
 func TestSession(t *testing.T) {
-	t.Parallel()
-
 	session := newSession(&SessionOptions{SQLMode: mysql.ModeNone, Timestamp: 1234567890, RowFormatVersion: "1"})
 	_, err := session.Txn(true)
 	require.NoError(t, err)
diff --git a/br/pkg/lightning/backend/backend_test.go b/br/pkg/lightning/backend/backend_test.go
index 0b347994192c4..d1a6f4e41a58d 100644
--- a/br/pkg/lightning/backend/backend_test.go
+++ b/br/pkg/lightning/backend/backend_test.go
@@ -39,7 +39,6 @@ func (s *backendSuite) tearDownTest() {
 }
 
 func TestOpenCloseImportCleanUpEngine(t *testing.T) {
-	t.Parallel()
 	s := createBackendSuite(t)
 	defer s.tearDownTest()
 	ctx := context.Background()
@@ -72,7 +71,6 @@ func TestOpenCloseImportCleanUpEngine(t *testing.T) {
 }
 
 func TestUnsafeCloseEngine(t *testing.T) {
-	t.Parallel()
 	s := createBackendSuite(t)
 	defer s.tearDownTest()
 
@@ -94,7 +92,6 @@ func TestUnsafeCloseEngine(t *testing.T) {
 }
 
 func TestUnsafeCloseEngineWithUUID(t *testing.T) {
-	t.Parallel()
 	s := createBackendSuite(t)
 	defer s.tearDownTest()
 
@@ -116,7 +113,6 @@ func TestUnsafeCloseEngineWithUUID(t *testing.T) {
 }
 
 func TestWriteEngine(t *testing.T) {
-	t.Parallel()
 	s := createBackendSuite(t)
 	defer s.tearDownTest()
 
@@ -155,7 +151,6 @@ func TestWriteEngine(t *testing.T) {
 }
 
 func TestWriteToEngineWithNothing(t *testing.T) {
-	t.Parallel()
 	s := createBackendSuite(t)
 	defer s.tearDownTest()
 
@@ -179,7 +174,6 @@ func TestWriteToEngineWithNothing(t *testing.T) {
 }
 
 func TestOpenEngineFailed(t *testing.T) {
-	t.Parallel()
 	s := createBackendSuite(t)
 	defer s.tearDownTest()
 
@@ -193,7 +187,6 @@ func TestOpenEngineFailed(t *testing.T) {
 }
 
 func TestWriteEngineFailed(t *testing.T) {
-	t.Parallel()
 	s := createBackendSuite(t)
 	defer s.tearDownTest()
 
@@ -221,7 +214,6 @@ func TestWriteEngineFailed(t *testing.T) {
 }
 
 func TestWriteBatchSendFailedWithRetry(t *testing.T) {
-	t.Parallel()
 	s := createBackendSuite(t)
 	defer s.tearDownTest()
 
@@ -249,7 +241,6 @@ func TestWriteBatchSendFailedWithRetry(t *testing.T) {
 }
 
 func TestImportFailedNoRetry(t *testing.T) {
-	t.Parallel()
 	s := createBackendSuite(t)
 	defer s.tearDownTest()
 
@@ -268,7 +259,6 @@ func TestImportFailedNoRetry(t *testing.T) {
 }
 
 func TestImportFailedWithRetry(t *testing.T) {
-	t.Parallel()
 	s := createBackendSuite(t)
 	defer s.tearDownTest()
 
@@ -289,7 +279,6 @@ func TestImportFailedWithRetry(t *testing.T) {
 }
 
 func TestImportFailedRecovered(t *testing.T) {
-	t.Parallel()
 	s := createBackendSuite(t)
 	defer s.tearDownTest()
 
@@ -312,7 +301,6 @@ func TestImportFailedRecovered(t *testing.T) {
 
 //nolint:interfacer // change test case signature causes check panicking.
 func TestClose(t *testing.T) {
-	t.Parallel()
 	s := createBackendSuite(t)
 	defer s.tearDownTest()
 
@@ -322,7 +310,6 @@ func TestClose(t *testing.T) {
 }
 
 func TestMakeEmptyRows(t *testing.T) {
-	t.Parallel()
 	s := createBackendSuite(t)
 	defer s.tearDownTest()
 
@@ -332,7 +319,6 @@ func TestMakeEmptyRows(t *testing.T) {
 }
 
 func TestNewEncoder(t *testing.T) {
-	t.Parallel()
 	s := createBackendSuite(t)
 	defer s.tearDownTest()
 
@@ -346,7 +332,6 @@ func TestNewEncoder(t *testing.T) {
 }
 
 func TestCheckDiskQuota(t *testing.T) {
-	t.Parallel()
 	s := createBackendSuite(t)
 	defer s.tearDownTest()
 
diff --git a/br/pkg/lightning/backend/importer/importer_test.go b/br/pkg/lightning/backend/importer/importer_test.go
index a0d7878ea5ecb..dd65db3ee4d5a 100644
--- a/br/pkg/lightning/backend/importer/importer_test.go
+++ b/br/pkg/lightning/backend/importer/importer_test.go
@@ -79,7 +79,6 @@ func (s *importerSuite) tearDownTest() {
 }
 
 func TestWriteRows(t *testing.T) {
-	t.Parallel()
 	s := createImportSuite(t)
 	defer s.tearDownTest()
 
@@ -117,7 +116,6 @@ func TestWriteRows(t *testing.T) {
 }
 
 func TestWriteHeadSendFailed(t *testing.T) {
-	t.Parallel()
 	s := createImportSuite(t)
 	defer s.tearDownTest()
 
@@ -142,7 +140,6 @@ func TestWriteHeadSendFailed(t *testing.T) {
 }
 
 func TestWriteBatchSendFailed(t *testing.T) {
-	t.Parallel()
 	s := createImportSuite(t)
 	defer s.tearDownTest()
 
@@ -174,7 +171,6 @@ func TestWriteBatchSendFailed(t *testing.T) {
 }
 
 func TestWriteCloseFailed(t *testing.T) {
-	t.Parallel()
 	s := createImportSuite(t)
 	defer s.tearDownTest()
 
@@ -206,7 +202,6 @@ func TestWriteCloseFailed(t *testing.T) {
 }
 
 func TestCloseImportCleanupEngine(t *testing.T) {
-	t.Parallel()
 	s := createImportSuite(t)
 	defer s.tearDownTest()
 
diff --git a/br/pkg/lightning/backend/tidb/tidb_test.go b/br/pkg/lightning/backend/tidb/tidb_test.go
index e6f14def964d2..9ab3e3ab9feaa 100644
--- a/br/pkg/lightning/backend/tidb/tidb_test.go
+++ b/br/pkg/lightning/backend/tidb/tidb_test.go
@@ -73,7 +73,6 @@ func (s *mysqlSuite) TearDownTest(t *testing.T) {
 }
 
 func TestWriteRowsReplaceOnDup(t *testing.T) {
-	t.Parallel()
 	s := createMysqlSuite(t)
 	defer s.TearDownTest(t)
 	s.mockDB.
@@ -132,7 +131,6 @@ func TestWriteRowsReplaceOnDup(t *testing.T) {
 }
 
 func TestWriteRowsIgnoreOnDup(t *testing.T) {
-	t.Parallel()
 	s := createMysqlSuite(t)
 	defer s.TearDownTest(t)
 	s.mockDB.
@@ -179,7 +177,6 @@ func TestWriteRowsIgnoreOnDup(t *testing.T) {
 }
 
 func TestWriteRowsErrorOnDup(t *testing.T) {
-	t.Parallel()
 	s := createMysqlSuite(t)
 	defer s.TearDownTest(t)
 	s.mockDB.
@@ -259,7 +256,6 @@ func testStrictMode(t *testing.T) {
 }
 
 func TestFetchRemoteTableModels_3_x(t *testing.T) {
-	t.Parallel()
 	s := createMysqlSuite(t)
 	defer s.TearDownTest(t)
 	s.mockDB.ExpectBegin()
@@ -294,7 +290,6 @@ func TestFetchRemoteTableModels_3_x(t *testing.T) {
 }
 
 func TestFetchRemoteTableModels_4_0(t *testing.T) {
-	t.Parallel()
 	s := createMysqlSuite(t)
 	defer s.TearDownTest(t)
 	s.mockDB.ExpectBegin()
@@ -332,7 +327,6 @@ func TestFetchRemoteTableModels_4_0(t *testing.T) {
 }
 
 func TestFetchRemoteTableModels_4_x_auto_increment(t *testing.T) {
-	t.Parallel()
 	s := createMysqlSuite(t)
 	defer s.TearDownTest(t)
 	s.mockDB.ExpectBegin()
@@ -370,7 +364,6 @@ func TestFetchRemoteTableModels_4_x_auto_increment(t *testing.T) {
 }
 
 func TestFetchRemoteTableModels_4_x_auto_random(t *testing.T) {
-	t.Parallel()
 	s := createMysqlSuite(t)
 	defer s.TearDownTest(t)
 	s.mockDB.ExpectBegin()
@@ -410,7 +403,6 @@ func TestFetchRemoteTableModels_4_x_auto_random(t *testing.T) {
 }
 
 func TestWriteRowsErrorNoRetry(t *testing.T) {
-	t.Parallel()
 	nonRetryableError := sql.ErrNoRows
 	s := createMysqlSuite(t)
 	defer s.TearDownTest(t)
@@ -436,7 +428,6 @@ func TestWriteRowsErrorNoRetry(t *testing.T) {
 }
 
 func TestWriteRowsErrorDowngradingAll(t *testing.T) {
-	t.Parallel()
 	nonRetryableError := sql.ErrNoRows
 	s := createMysqlSuite(t)
 	defer s.TearDownTest(t)
@@ -503,7 +494,6 @@ func TestWriteRowsErrorDowngradingAll(t *testing.T) {
 }
 
 func TestWriteRowsErrorDowngradingExceedThreshold(t *testing.T) {
-	t.Parallel()
 	nonRetryableError := sql.ErrNoRows
 	s := createMysqlSuite(t)
 	defer s.TearDownTest(t)
@@ -608,7 +598,6 @@ func encodeRowsTiDB(t *testing.T, b backend.Backend, tbl table.Table) kv.Rows {
 }
 
 func TestEncodeRowForRecord(t *testing.T) {
-	t.Parallel()
 	s := createMysqlSuite(t)
 
 	// for a correct row, the will encode a correct result
diff --git a/br/pkg/lightning/lightning.go b/br/pkg/lightning/lightning.go
index 575b661be6cac..9fc40cdf77144 100644
--- a/br/pkg/lightning/lightning.go
+++ b/br/pkg/lightning/lightning.go
@@ -296,6 +296,19 @@ func (l *Lightning) run(taskCtx context.Context, taskCfg *config.Config, g glue.
 		return errors.Annotate(err, "create storage failed")
 	}
 
+	// return expectedErr means at least meet one file
+	expectedErr := errors.New("Stop Iter")
+	walkErr := s.WalkDir(ctx, &storage.WalkOption{ListCount: 1}, func(string, int64) error {
+		// return an error when meet the first regular file to break the walk loop
+		return expectedErr
+	})
+	if !errors.ErrorEqual(walkErr, expectedErr) {
+		if walkErr == nil {
+			return errors.Errorf("data-source-dir '%s' doesn't exist or contains no files", taskCfg.Mydumper.SourceDir)
+		}
+		return errors.Annotatef(walkErr, "visit data-source-dir '%s' failed", taskCfg.Mydumper.SourceDir)
+	}
+
 	loadTask := log.L().Begin(zap.InfoLevel, "load data source")
 	var mdl *mydump.MDLoader
 	mdl, err = mydump.NewMyDumpLoaderWithStore(ctx, taskCfg, s)
diff --git a/br/pkg/logutil/logging_test.go b/br/pkg/logutil/logging_test.go
index 28ed6a8f708b2..fc4b415a89735 100644
--- a/br/pkg/logutil/logging_test.go
+++ b/br/pkg/logutil/logging_test.go
@@ -46,7 +46,6 @@ func newFile(j int) *backuppb.File {
 }
 
 func TestRater(t *testing.T) {
-	t.Parallel()
 	m := prometheus.NewCounter(prometheus.CounterOpts{
 		Namespace: "testing",
 		Name:      "rater",
@@ -65,13 +64,11 @@ func TestRater(t *testing.T) {
 }
 
 func TestFile(t *testing.T) {
-	t.Parallel()
 	assertTrimEqual(t, logutil.File(newFile(1)),
 		`{"file": {"name": "1", "CF": "write", "sha256": "31", "startKey": "31", "endKey": "32", "startVersion": 1, "endVersion": 2, "totalKvs": 1, "totalBytes": 1, "CRC64Xor": 1}}`)
 }
 
 func TestFiles(t *testing.T) {
-	t.Parallel()
 	cases := []struct {
 		count  int
 		expect string
@@ -96,7 +93,6 @@ func TestFiles(t *testing.T) {
 }
 
 func TestKey(t *testing.T) {
-	t.Parallel()
 	encoder := zapcore.NewConsoleEncoder(zapcore.EncoderConfig{})
 	out, err := encoder.EncodeEntry(zapcore.Entry{}, []zap.Field{logutil.Key("test", []byte{0, 1, 2, 3})})
 	require.NoError(t, err)
@@ -104,7 +100,6 @@ func TestKey(t *testing.T) {
 }
 
 func TestKeys(t *testing.T) {
-	t.Parallel()
 	cases := []struct {
 		count  int
 		expect string
@@ -129,7 +124,6 @@ func TestKeys(t *testing.T) {
 }
 
 func TestRewriteRule(t *testing.T) {
-	t.Parallel()
 	rule := &import_sstpb.RewriteRule{
 		OldKeyPrefix: []byte("old"),
 		NewKeyPrefix: []byte("new"),
@@ -143,7 +137,6 @@ func TestRewriteRule(t *testing.T) {
 }
 
 func TestRegion(t *testing.T) {
-	t.Parallel()
 	region := &metapb.Region{
 		Id:          1,
 		StartKey:    []byte{0x00, 0x01},
@@ -157,14 +150,12 @@ func TestRegion(t *testing.T) {
 }
 
 func TestLeader(t *testing.T) {
-	t.Parallel()
 	leader := &metapb.Peer{Id: 2, StoreId: 3}
 
 	assertTrimEqual(t, logutil.Leader(leader), `{"leader": "id:2 store_id:3 "}`)
 }
 
 func TestSSTMeta(t *testing.T) {
-	t.Parallel()
 	meta := &import_sstpb.SSTMeta{
 		Uuid: []byte("mock uuid"),
 		Range: &import_sstpb.Range{
@@ -183,14 +174,12 @@ func TestSSTMeta(t *testing.T) {
 }
 
 func TestShortError(t *testing.T) {
-	t.Parallel()
 	err := errors.Annotate(berrors.ErrInvalidArgument, "test")
 
 	assertTrimEqual(t, logutil.ShortError(err), `{"error": "test: [BR:Common:ErrInvalidArgument]invalid argument"}`)
 }
 
 func TestContextual(t *testing.T) {
-	t.Parallel()
 	testCore, logs := observer.New(zap.InfoLevel)
 	logutil.ResetGlobalLogger(zap.New(testCore))
 
diff --git a/br/pkg/membuf/buffer_test.go b/br/pkg/membuf/buffer_test.go
index 0271aee54c7ef..c5d095d299f9c 100644
--- a/br/pkg/membuf/buffer_test.go
+++ b/br/pkg/membuf/buffer_test.go
@@ -40,8 +40,6 @@ func (t *testAllocator) Free(_ []byte) {
 }
 
 func TestBufferPool(t *testing.T) {
-	t.Parallel()
-
 	allocator := &testAllocator{}
 	pool := NewPool(2, allocator)
 
@@ -69,8 +67,6 @@ func TestBufferPool(t *testing.T) {
 }
 
 func TestBufferIsolation(t *testing.T) {
-	t.Parallel()
-
 	bytesBuf := NewBuffer()
 	defer bytesBuf.Destroy()
 
diff --git a/br/pkg/metautil/metafile_test.go b/br/pkg/metautil/metafile_test.go
index 2553e862594f6..6fe79a2b8e610 100644
--- a/br/pkg/metautil/metafile_test.go
+++ b/br/pkg/metautil/metafile_test.go
@@ -24,8 +24,6 @@ func checksum(m *backuppb.MetaFile) []byte {
 }
 
 func TestWalkMetaFileEmpty(t *testing.T) {
-	t.Parallel()
-
 	files := []*backuppb.MetaFile{}
 	collect := func(m *backuppb.MetaFile) { files = append(files, m) }
 	cipher := backuppb.CipherInfo{
@@ -46,8 +44,6 @@ func TestWalkMetaFileEmpty(t *testing.T) {
 }
 
 func TestWalkMetaFileLeaf(t *testing.T) {
-	t.Parallel()
-
 	leaf := &backuppb.MetaFile{Schemas: []*backuppb.Schema{
 		{Db: []byte("db"), Table: []byte("table")},
 	}}
@@ -64,8 +60,6 @@ func TestWalkMetaFileLeaf(t *testing.T) {
 }
 
 func TestWalkMetaFileInvalid(t *testing.T) {
-	t.Parallel()
-
 	controller := gomock.NewController(t)
 	defer controller.Finish()
 	mockStorage := mockstorage.NewMockExternalStorage(controller)
@@ -91,8 +85,6 @@ func TestWalkMetaFileInvalid(t *testing.T) {
 }
 
 func TestWalkMetaFile(t *testing.T) {
-	t.Parallel()
-
 	controller := gomock.NewController(t)
 	defer controller.Finish()
 	mockStorage := mockstorage.NewMockExternalStorage(controller)
@@ -161,8 +153,6 @@ type encryptTest struct {
 }
 
 func TestEncryptAndDecrypt(t *testing.T) {
-	t.Parallel()
-
 	originalData := []byte("pingcap")
 	testCases := []encryptTest{
 		{
diff --git a/br/pkg/restore/split_test.go b/br/pkg/restore/split_test.go
index 7a39785af2cb9..a4bd794f1a0a1 100644
--- a/br/pkg/restore/split_test.go
+++ b/br/pkg/restore/split_test.go
@@ -237,7 +237,6 @@ func (b *assertRetryLessThanBackoffer) Attempt() int {
 }
 
 func TestScatterFinishInTime(t *testing.T) {
-	t.Parallel()
 	client := initTestClient()
 	ranges := initRanges()
 	rewriteRules := initRewriteRules()
@@ -283,7 +282,6 @@ func TestScatterFinishInTime(t *testing.T) {
 //   [, aay), [aay, bba), [bba, bbf), [bbf, bbh), [bbh, bbj),
 //   [bbj, cca), [cca, xxe), [xxe, xxz), [xxz, )
 func TestSplitAndScatter(t *testing.T) {
-	t.Parallel()
 	client := initTestClient()
 	ranges := initRanges()
 	rewriteRules := initRewriteRules()
diff --git a/br/pkg/rtree/logging_test.go b/br/pkg/rtree/logging_test.go
index f86dbb0ad1eda..9630cda766aeb 100644
--- a/br/pkg/rtree/logging_test.go
+++ b/br/pkg/rtree/logging_test.go
@@ -15,7 +15,6 @@ import (
 )
 
 func TestLogRanges(t *testing.T) {
-	t.Parallel()
 	cases := []struct {
 		count  int
 		expect string
diff --git a/br/pkg/rtree/rtree_test.go b/br/pkg/rtree/rtree_test.go
index a4630f4b8c945..a5fce76080f52 100644
--- a/br/pkg/rtree/rtree_test.go
+++ b/br/pkg/rtree/rtree_test.go
@@ -18,7 +18,6 @@ func newRange(start, end []byte) *rtree.Range {
 }
 
 func TestRangeTree(t *testing.T) {
-	t.Parallel()
 	rangeTree := rtree.NewRangeTree()
 	require.Nil(t, rangeTree.Get(newRange([]byte(""), []byte(""))))
 
@@ -123,7 +122,6 @@ func TestRangeTree(t *testing.T) {
 }
 
 func TestRangeIntersect(t *testing.T) {
-	t.Parallel()
 	rg := newRange([]byte("a"), []byte("c"))
 
 	start, end, isIntersect := rg.Intersect([]byte(""), []byte(""))
diff --git a/br/pkg/storage/gcs.go b/br/pkg/storage/gcs.go
index e4835e0eb6111..c54141b8ee560 100644
--- a/br/pkg/storage/gcs.go
+++ b/br/pkg/storage/gcs.go
@@ -276,14 +276,6 @@ func newGCSStorage(ctx context.Context, gcs *backuppb.GCS, opts *ExternalStorage
 		// so we need find sst in slash directory
 		gcs.Prefix += "//"
 	}
-	// TODO remove it after BR remove cfg skip-check-path
-	if !opts.SkipCheckPath {
-		// check bucket exists
-		_, err = bucket.Attrs(ctx)
-		if err != nil {
-			return nil, errors.Annotatef(err, "gcs://%s/%s", gcs.Bucket, gcs.Prefix)
-		}
-	}
 	return &gcsStorage{gcs: gcs, bucket: bucket}, nil
 }
 
diff --git a/br/pkg/storage/s3.go b/br/pkg/storage/s3.go
index 2c07b5af2cad0..6accafee7363d 100644
--- a/br/pkg/storage/s3.go
+++ b/br/pkg/storage/s3.go
@@ -283,14 +283,6 @@ func newS3Storage(backend *backuppb.S3, opts *ExternalStorageOptions) (*S3Storag
 	}
 
 	c := s3.New(ses)
-	// TODO remove it after BR remove cfg skip-check-path
-	if !opts.SkipCheckPath {
-		err = checkS3Bucket(c, &qs)
-		if err != nil {
-			return nil, errors.Annotatef(berrors.ErrStorageInvalidConfig, "Bucket %s is not accessible: %v", qs.Bucket, err)
-		}
-	}
-
 	if len(qs.Prefix) > 0 && !strings.HasSuffix(qs.Prefix, "/") {
 		qs.Prefix += "/"
 	}
diff --git a/br/pkg/storage/s3_test.go b/br/pkg/storage/s3_test.go
index 413f5e8881da1..cf30828b07c65 100644
--- a/br/pkg/storage/s3_test.go
+++ b/br/pkg/storage/s3_test.go
@@ -288,7 +288,6 @@ func (s *s3Suite) TestS3Storage(c *C) {
 		_, err := New(ctx, s3, &ExternalStorageOptions{
 			SendCredentials:  test.sendCredential,
 			CheckPermissions: test.hackPermission,
-			SkipCheckPath:    true,
 		})
 		if test.errReturn {
 			c.Assert(err, NotNil)
@@ -414,7 +413,7 @@ func (s *s3Suite) TestS3Storage(c *C) {
 func (s *s3Suite) TestS3URI(c *C) {
 	backend, err := ParseBackend("s3://bucket/prefix/", nil)
 	c.Assert(err, IsNil)
-	storage, err := New(context.Background(), backend, &ExternalStorageOptions{SkipCheckPath: true})
+	storage, err := New(context.Background(), backend, &ExternalStorageOptions{})
 	c.Assert(err, IsNil)
 	c.Assert(storage.URI(), Equals, "s3://bucket/prefix/")
 }
diff --git a/br/pkg/storage/storage.go b/br/pkg/storage/storage.go
index af05abac398fa..177656fc378a0 100644
--- a/br/pkg/storage/storage.go
+++ b/br/pkg/storage/storage.go
@@ -121,18 +121,6 @@ type ExternalStorageOptions struct {
 	// NoCredentials means that no cloud credentials are supplied to BR
 	NoCredentials bool
 
-	// SkipCheckPath marks whether to skip checking path's existence.
-	//
-	// This should only be set to true in testing, to avoid interacting with the
-	// real world.
-	// When this field is false (i.e. path checking is enabled), the New()
-	// function will ensure the path referred by the backend exists by
-	// recursively creating the folders. This will also throw an error if such
-	// operation is impossible (e.g. when the bucket storing the path is missing).
-
-	// deprecated: use checkPermissions and specify the checkPermission instead.
-	SkipCheckPath bool
-
 	// HTTPClient to use. The created storage may ignore this field if it is not
 	// directly using HTTP (e.g. the local storage).
 	HTTPClient *http.Client
@@ -148,7 +136,6 @@ type ExternalStorageOptions struct {
 func Create(ctx context.Context, backend *backuppb.StorageBackend, sendCreds bool) (ExternalStorage, error) {
 	return New(ctx, backend, &ExternalStorageOptions{
 		SendCredentials: sendCreds,
-		SkipCheckPath:   false,
 		HTTPClient:      nil,
 	})
 }
diff --git a/br/pkg/summary/collector_test.go b/br/pkg/summary/collector_test.go
index c2328ee7c2c98..d706b985343f1 100644
--- a/br/pkg/summary/collector_test.go
+++ b/br/pkg/summary/collector_test.go
@@ -11,8 +11,6 @@ import (
 )
 
 func TestSumDurationInt(t *testing.T) {
-	t.Parallel()
-
 	fields := []zap.Field{}
 	logger := func(msg string, fs ...zap.Field) {
 		fields = append(fields, fs...)
diff --git a/br/pkg/task/backup.go b/br/pkg/task/backup.go
index 7a9037c20f80c..87461f53bab74 100644
--- a/br/pkg/task/backup.go
+++ b/br/pkg/task/backup.go
@@ -257,7 +257,6 @@ func RunBackup(c context.Context, g glue.Glue, cmdName string, cfg *BackupConfig
 	opts := storage.ExternalStorageOptions{
 		NoCredentials:   cfg.NoCreds,
 		SendCredentials: cfg.SendCreds,
-		SkipCheckPath:   cfg.SkipCheckPath,
 	}
 	if err = client.SetStorage(ctx, u, &opts); err != nil {
 		return errors.Trace(err)
diff --git a/br/pkg/task/backup_raw.go b/br/pkg/task/backup_raw.go
index d8d11ea95c3a1..febe151218706 100644
--- a/br/pkg/task/backup_raw.go
+++ b/br/pkg/task/backup_raw.go
@@ -150,7 +150,6 @@ func RunBackupRaw(c context.Context, g glue.Glue, cmdName string, cfg *RawKvConf
 	opts := storage.ExternalStorageOptions{
 		NoCredentials:   cfg.NoCreds,
 		SendCredentials: cfg.SendCreds,
-		SkipCheckPath:   cfg.SkipCheckPath,
 	}
 	if err = client.SetStorage(ctx, u, &opts); err != nil {
 		return errors.Trace(err)
diff --git a/br/pkg/task/common.go b/br/pkg/task/common.go
index 4ae54f03cde5a..357c7d267e449 100644
--- a/br/pkg/task/common.go
+++ b/br/pkg/task/common.go
@@ -485,6 +485,9 @@ func (cfg *Config) ParseFromFlags(flags *pflag.FlagSet) error {
 	if cfg.SkipCheckPath, err = flags.GetBool(flagSkipCheckPath); err != nil {
 		return errors.Trace(err)
 	}
+	if cfg.SkipCheckPath {
+		log.L().Info("--skip-check-path is deprecated, need explicitly set it anymore")
+	}
 
 	if err = cfg.parseCipherInfo(flags); err != nil {
 		return errors.Trace(err)
@@ -548,7 +551,6 @@ func storageOpts(cfg *Config) *storage.ExternalStorageOptions {
 	return &storage.ExternalStorageOptions{
 		NoCredentials:   cfg.NoCreds,
 		SendCredentials: cfg.SendCreds,
-		SkipCheckPath:   cfg.SkipCheckPath,
 	}
 }
 
diff --git a/br/pkg/task/restore.go b/br/pkg/task/restore.go
index a80549d005905..ae46f15b1f6ce 100644
--- a/br/pkg/task/restore.go
+++ b/br/pkg/task/restore.go
@@ -249,7 +249,6 @@ func RunRestore(c context.Context, g glue.Glue, cmdName string, cfg *RestoreConf
 	opts := storage.ExternalStorageOptions{
 		NoCredentials:   cfg.NoCreds,
 		SendCredentials: cfg.SendCreds,
-		SkipCheckPath:   cfg.SkipCheckPath,
 	}
 	if err = client.SetStorage(ctx, u, &opts); err != nil {
 		return errors.Trace(err)
diff --git a/br/pkg/utils/backoff_test.go b/br/pkg/utils/backoff_test.go
index e8af459c78de6..9ee312f24feab 100644
--- a/br/pkg/utils/backoff_test.go
+++ b/br/pkg/utils/backoff_test.go
@@ -16,8 +16,6 @@ import (
 )
 
 func TestBackoffWithSuccess(t *testing.T) {
-	t.Parallel()
-
 	var counter int
 	backoffer := utils.NewBackoffer(10, time.Nanosecond, time.Nanosecond)
 	err := utils.WithRetry(context.Background(), func() error {
@@ -37,8 +35,6 @@ func TestBackoffWithSuccess(t *testing.T) {
 }
 
 func TestBackoffWithFatalError(t *testing.T) {
-	t.Parallel()
-
 	var counter int
 	backoffer := utils.NewBackoffer(10, time.Nanosecond, time.Nanosecond)
 	gRPCError := status.Error(codes.Unavailable, "transport is closing")
@@ -66,8 +62,6 @@ func TestBackoffWithFatalError(t *testing.T) {
 }
 
 func TestBackoffWithFatalRawGRPCError(t *testing.T) {
-	t.Parallel()
-
 	var counter int
 	canceledError := status.Error(codes.Canceled, "context canceled")
 	backoffer := utils.NewBackoffer(10, time.Nanosecond, time.Nanosecond)
@@ -80,8 +74,6 @@ func TestBackoffWithFatalRawGRPCError(t *testing.T) {
 }
 
 func TestBackoffWithRetryableError(t *testing.T) {
-	t.Parallel()
-
 	var counter int
 	backoffer := utils.NewBackoffer(10, time.Nanosecond, time.Nanosecond)
 	err := utils.WithRetry(context.Background(), func() error {
@@ -104,8 +96,6 @@ func TestBackoffWithRetryableError(t *testing.T) {
 }
 
 func TestPdBackoffWithRetryableError(t *testing.T) {
-	t.Parallel()
-
 	var counter int
 	backoffer := utils.NewPDReqBackoffer()
 	gRPCError := status.Error(codes.Unavailable, "transport is closing")
diff --git a/br/pkg/utils/env_test.go b/br/pkg/utils/env_test.go
index 6934ef3c6e870..46cbb21c1a63d 100644
--- a/br/pkg/utils/env_test.go
+++ b/br/pkg/utils/env_test.go
@@ -10,8 +10,6 @@ import (
 )
 
 func TestProxyFields(t *testing.T) {
-	t.Parallel()
-
 	revIndex := map[string]int{
 		"http_proxy":  0,
 		"https_proxy": 1,
diff --git a/br/pkg/utils/json_test.go b/br/pkg/utils/json_test.go
index a026aa4b81733..691521b7bf25a 100644
--- a/br/pkg/utils/json_test.go
+++ b/br/pkg/utils/json_test.go
@@ -207,8 +207,6 @@ var testMetaJSONs = [][]byte{
 }
 
 func TestEncodeAndDecode(t *testing.T) {
-	t.Parallel()
-
 	for _, testMetaJSON := range testMetaJSONs {
 		meta, err := UnmarshalBackupMeta(testMetaJSON)
 		require.NoError(t, err)
diff --git a/br/pkg/utils/key_test.go b/br/pkg/utils/key_test.go
index 56b88a4720f21..f9ce1c012b88d 100644
--- a/br/pkg/utils/key_test.go
+++ b/br/pkg/utils/key_test.go
@@ -10,8 +10,6 @@ import (
 )
 
 func TestParseKey(t *testing.T) {
-	t.Parallel()
-
 	// test rawKey
 	testRawKey := []struct {
 		rawKey string
@@ -94,8 +92,6 @@ func TestParseKey(t *testing.T) {
 }
 
 func TestCompareEndKey(t *testing.T) {
-	t.Parallel()
-
 	// test endKey
 	testCase := []struct {
 		key1 []byte
diff --git a/br/pkg/utils/math_test.go b/br/pkg/utils/math_test.go
index 45a3da7587ffd..cce36cf342222 100644
--- a/br/pkg/utils/math_test.go
+++ b/br/pkg/utils/math_test.go
@@ -9,8 +9,6 @@ import (
 )
 
 func TestMinInt(t *testing.T) {
-	t.Parallel()
-
 	require.Equal(t, 1, MinInt(1, 2))
 	require.Equal(t, 1, MinInt(2, 1))
 	require.Equal(t, 1, MinInt(4, 2, 1, 3))
@@ -18,8 +16,6 @@ func TestMinInt(t *testing.T) {
 }
 
 func TestMaxInt(t *testing.T) {
-	t.Parallel()
-
 	require.Equal(t, 2, MaxInt(1, 2))
 	require.Equal(t, 2, MaxInt(2, 1))
 	require.Equal(t, 4, MaxInt(4, 2, 1, 3))
@@ -27,8 +23,6 @@ func TestMaxInt(t *testing.T) {
 }
 
 func TestClampInt(t *testing.T) {
-	t.Parallel()
-
 	require.Equal(t, 3, ClampInt(100, 1, 3))
 	require.Equal(t, 2, ClampInt(2, 1, 3))
 	require.Equal(t, 1, ClampInt(0, 1, 3))
@@ -37,8 +31,6 @@ func TestClampInt(t *testing.T) {
 }
 
 func TestMinInt64(t *testing.T) {
-	t.Parallel()
-
 	require.Equal(t, 1, MinInt(1, 2))
 	require.Equal(t, 1, MinInt(2, 1))
 	require.Equal(t, 1, MinInt(4, 2, 1, 3))
@@ -46,8 +38,6 @@ func TestMinInt64(t *testing.T) {
 }
 
 func TestNextPowerOfTwo(t *testing.T) {
-	t.Parallel()
-
 	require.Equal(t, int64(1), NextPowerOfTwo(1))
 	require.Equal(t, int64(4), NextPowerOfTwo(3))
 	require.Equal(t, int64(256), NextPowerOfTwo(255))
diff --git a/br/pkg/utils/progress_test.go b/br/pkg/utils/progress_test.go
index a8503c966db39..3d3e24c3b29ba 100644
--- a/br/pkg/utils/progress_test.go
+++ b/br/pkg/utils/progress_test.go
@@ -20,8 +20,6 @@ func (t *testWriter) Write(p []byte) (int, error) {
 }
 
 func TestProgress(t *testing.T) {
-	t.Parallel()
-
 	ctx, cancel := context.WithCancel(context.Background())
 
 	var p string
diff --git a/br/pkg/utils/retry_test.go b/br/pkg/utils/retry_test.go
index 52d65fd1c7a23..f27698dcf5f9a 100644
--- a/br/pkg/utils/retry_test.go
+++ b/br/pkg/utils/retry_test.go
@@ -17,8 +17,6 @@ import (
 )
 
 func TestIsRetryableError(t *testing.T) {
-	t.Parallel()
-
 	require.False(t, IsRetryableError(context.Canceled))
 	require.False(t, IsRetryableError(context.DeadlineExceeded))
 	require.False(t, IsRetryableError(io.EOF))
diff --git a/br/pkg/utils/safe_point_test.go b/br/pkg/utils/safe_point_test.go
index e77c17c3a23d9..af7dde167ed16 100644
--- a/br/pkg/utils/safe_point_test.go
+++ b/br/pkg/utils/safe_point_test.go
@@ -13,8 +13,6 @@ import (
 )
 
 func TestCheckGCSafepoint(t *testing.T) {
-	t.Parallel()
-
 	ctx := context.Background()
 	pdClient := &mockSafePoint{safepoint: 2333}
 	{
@@ -67,8 +65,6 @@ func (m *mockSafePoint) UpdateGCSafePoint(ctx context.Context, safePoint uint64)
 }
 
 func TestStartServiceSafePointKeeper(t *testing.T) {
-	t.Parallel()
-
 	pdClient := &mockSafePoint{safepoint: 2333}
 
 	cases := []struct {
diff --git a/br/pkg/utils/schema_test.go b/br/pkg/utils/schema_test.go
index 243b72932322c..95d649000d9ce 100644
--- a/br/pkg/utils/schema_test.go
+++ b/br/pkg/utils/schema_test.go
@@ -27,8 +27,6 @@ func mockBackupMeta(mockSchemas []*backuppb.Schema, mockFiles []*backuppb.File)
 }
 
 func TestLoadBackupMeta(t *testing.T) {
-	t.Parallel()
-
 	testDir := t.TempDir()
 	store, err := storage.NewLocalStorage(testDir)
 	require.NoError(t, err)
@@ -105,8 +103,6 @@ func TestLoadBackupMeta(t *testing.T) {
 }
 
 func TestLoadBackupMetaPartionTable(t *testing.T) {
-	t.Parallel()
-
 	testDir := t.TempDir()
 	store, err := storage.NewLocalStorage(testDir)
 	require.NoError(t, err)
diff --git a/br/pkg/version/build/info_test.go b/br/pkg/version/build/info_test.go
index 53c2e6fbf9bb4..a891c8c65e3ca 100644
--- a/br/pkg/version/build/info_test.go
+++ b/br/pkg/version/build/info_test.go
@@ -10,8 +10,6 @@ import (
 )
 
 func TestInfo(t *testing.T) {
-	t.Parallel()
-
 	info := Info()
 	lines := strings.Split(info, "\n")
 	require.Regexp(t, "^Release Version", lines[0])
diff --git a/br/pkg/version/version_test.go b/br/pkg/version/version_test.go
index d976b7cd7589f..f2369c964029c 100644
--- a/br/pkg/version/version_test.go
+++ b/br/pkg/version/version_test.go
@@ -168,8 +168,6 @@ func TestCheckClusterVersion(t *testing.T) {
 }
 
 func TestCompareVersion(t *testing.T) {
-	t.Parallel()
-
 	require.Equal(t, -1, semver.New("4.0.0-rc").Compare(*semver.New("4.0.0-rc.2")))
 	require.Equal(t, -1, semver.New("4.0.0-beta.3").Compare(*semver.New("4.0.0-rc.2")))
 	require.Equal(t, -1, semver.New("4.0.0-rc.1").Compare(*semver.New("4.0.0")))
@@ -210,8 +208,6 @@ func TestNextMajorVersion(t *testing.T) {
 }
 
 func TestExtractTiDBVersion(t *testing.T) {
-	t.Parallel()
-
 	vers, err := ExtractTiDBVersion("5.7.10-TiDB-v2.1.0-rc.1-7-g38c939f")
 	require.NoError(t, err)
 	require.Equal(t, *semver.New("2.1.0-rc.1"), *vers)
@@ -257,8 +253,6 @@ func TestExtractTiDBVersion(t *testing.T) {
 }
 
 func TestCheckVersion(t *testing.T) {
-	t.Parallel()
-
 	err := CheckVersion("TiNB", *semver.New("2.3.5"), *semver.New("2.1.0"), *semver.New("3.0.0"))
 	require.NoError(t, err)
 
@@ -285,8 +279,6 @@ func versionEqualCheck(source *semver.Version, target *semver.Version) (result b
 }
 
 func TestNormalizeBackupVersion(t *testing.T) {
-	t.Parallel()
-
 	cases := []struct {
 		target string
 		source string
@@ -307,7 +299,6 @@ func TestNormalizeBackupVersion(t *testing.T) {
 }
 
 func TestDetectServerInfo(t *testing.T) {
-	t.Parallel()
 	db, mock, err := sqlmock.New()
 	require.NoError(t, err)
 	defer db.Close()
diff --git a/br/tests/lightning_s3/run.sh b/br/tests/lightning_s3/run.sh
index 6fed0af2b81da..5b2973784fd7e 100755
--- a/br/tests/lightning_s3/run.sh
+++ b/br/tests/lightning_s3/run.sh
@@ -62,6 +62,20 @@ _EOF_
 run_sql "DROP DATABASE IF EXISTS $DB;"
 run_sql "DROP TABLE IF EXISTS $DB.$TABLE;"
 
+# test not exist path
+rm -f $TEST_DIR/lightning.log
+SOURCE_DIR="s3://$BUCKET/not-exist-path?endpoint=http%3A//127.0.0.1%3A9900&access_key=$MINIO_ACCESS_KEY&secret_access_key=$MINIO_SECRET_KEY&force_path_style=true"
+! run_lightning -d $SOURCE_DIR --backend local 2> /dev/null
+grep -Eq "data-source-dir .* doesn't exist or contains no files" $TEST_DIR/lightning.log
+
+# test empty dir
+rm -f $TEST_DIR/lightning.log
+emptyPath=empty-bucket/empty-path
+mkdir -p $DBPATH/$emptyPath
+SOURCE_DIR="s3://$emptyPath/not-exist-path?endpoint=http%3A//127.0.0.1%3A9900&access_key=$MINIO_ACCESS_KEY&secret_access_key=$MINIO_SECRET_KEY&force_path_style=true"
+! run_lightning -d $SOURCE_DIR --backend local 2> /dev/null
+grep -Eq "data-source-dir .* doesn't exist or contains no files" $TEST_DIR/lightning.log
+
 SOURCE_DIR="s3://$BUCKET/?endpoint=http%3A//127.0.0.1%3A9900&access_key=$MINIO_ACCESS_KEY&secret_access_key=$MINIO_SECRET_KEY&force_path_style=true"
 run_lightning -d $SOURCE_DIR --backend local 2> /dev/null
 run_sql "SELECT count(*), sum(i) FROM \`$DB\`.$TABLE"
diff --git a/config/config_test.go b/config/config_test.go
index eaa8e5ea16756..ab3edc62a0fc4 100644
--- a/config/config_test.go
+++ b/config/config_test.go
@@ -33,7 +33,6 @@ import (
 )
 
 func TestAtomicBoolUnmarshal(t *testing.T) {
-	t.Parallel()
 	type data struct {
 		Ab AtomicBool `toml:"ab"`
 	}
@@ -59,8 +58,6 @@ func TestAtomicBoolUnmarshal(t *testing.T) {
 }
 
 func TestNullableBoolUnmarshal(t *testing.T) {
-	t.Parallel()
-
 	var nb = nullableBool{false, false}
 	data, err := json.Marshal(nb)
 	require.NoError(t, err)
@@ -480,8 +477,6 @@ xkNuJ2BlEGkwWLiRbKy1lNBBFUXKuhh3L/EIY10WTnr3TQzeL6H1
 }
 
 func TestOOMActionValid(t *testing.T) {
-	t.Parallel()
-
 	c1 := NewConfig()
 	tests := []struct {
 		oomAction string
@@ -500,8 +495,6 @@ func TestOOMActionValid(t *testing.T) {
 }
 
 func TestTxnTotalSizeLimitValid(t *testing.T) {
-	t.Parallel()
-
 	conf := NewConfig()
 	tests := []struct {
 		limit uint64
@@ -521,8 +514,6 @@ func TestTxnTotalSizeLimitValid(t *testing.T) {
 }
 
 func TestPreparePlanCacheValid(t *testing.T) {
-	t.Parallel()
-
 	conf := NewConfig()
 	tests := map[PreparedPlanCache]bool{
 		{Enabled: true, Capacity: 0}:                        false,
@@ -538,8 +529,6 @@ func TestPreparePlanCacheValid(t *testing.T) {
 }
 
 func TestMaxIndexLength(t *testing.T) {
-	t.Parallel()
-
 	conf := NewConfig()
 	checkValid := func(indexLen int, shouldBeValid bool) {
 		conf.MaxIndexLength = indexLen
@@ -552,8 +541,6 @@ func TestMaxIndexLength(t *testing.T) {
 }
 
 func TestIndexLimit(t *testing.T) {
-	t.Parallel()
-
 	conf := NewConfig()
 	checkValid := func(indexLimit int, shouldBeValid bool) {
 		conf.IndexLimit = indexLimit
@@ -566,8 +553,6 @@ func TestIndexLimit(t *testing.T) {
 }
 
 func TestTableColumnCountLimit(t *testing.T) {
-	t.Parallel()
-
 	conf := NewConfig()
 	checkValid := func(tableColumnLimit int, shouldBeValid bool) {
 		conf.TableColumnCountLimit = uint32(tableColumnLimit)
@@ -580,8 +565,6 @@ func TestTableColumnCountLimit(t *testing.T) {
 }
 
 func TestEncodeDefTempStorageDir(t *testing.T) {
-	t.Parallel()
-
 	tests := []struct {
 		host       string
 		statusHost string
@@ -644,8 +627,6 @@ func TestModifyThroughLDFlags(t *testing.T) {
 }
 
 func TestSecurityValid(t *testing.T) {
-	t.Parallel()
-
 	c1 := NewConfig()
 	tests := []struct {
 		spilledFileEncryptionMethod string
@@ -664,8 +645,6 @@ func TestSecurityValid(t *testing.T) {
 }
 
 func TestTcpNoDelay(t *testing.T) {
-	t.Parallel()
-
 	c1 := NewConfig()
 	//check default value
 	require.True(t, c1.Performance.TCPNoDelay)
diff --git a/config/config_util_test.go b/config/config_util_test.go
index baf06b4a35082..f23c47f8dd796 100644
--- a/config/config_util_test.go
+++ b/config/config_util_test.go
@@ -25,8 +25,6 @@ import (
 )
 
 func TestCloneConf(t *testing.T) {
-	t.Parallel()
-
 	c1, err := CloneConf(&defaultConf)
 	require.NoError(t, err)
 	c2, err := CloneConf(c1)
@@ -44,8 +42,6 @@ func TestCloneConf(t *testing.T) {
 }
 
 func TestMergeConfigItems(t *testing.T) {
-	t.Parallel()
-
 	oriConf, _ := CloneConf(&defaultConf)
 	oldConf, _ := CloneConf(oriConf)
 	newConf, _ := CloneConf(oldConf)
@@ -96,8 +92,6 @@ func TestMergeConfigItems(t *testing.T) {
 }
 
 func TestFlattenConfig(t *testing.T) {
-	t.Parallel()
-
 	toJSONStr := func(v interface{}) string {
 		str, err := json.Marshal(v)
 		require.NoError(t, err)
diff --git a/ddl/db_cache_test.go b/ddl/db_cache_test.go
index dd475e1e8506f..120c0c687e049 100644
--- a/ddl/db_cache_test.go
+++ b/ddl/db_cache_test.go
@@ -46,7 +46,6 @@ func testGetTableByNameT(t *testing.T, ctx sessionctx.Context, db, table string)
 }
 
 func TestAlterPartitionCache(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -77,7 +76,6 @@ func TestAlterPartitionCache(t *testing.T) {
 }
 
 func TestAlterViewTableCache(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -90,7 +88,6 @@ func TestAlterViewTableCache(t *testing.T) {
 }
 
 func TestAlterTableNoCache(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -115,7 +112,6 @@ func TestAlterTableNoCache(t *testing.T) {
 }
 
 func TestIndexOnCacheTable(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
diff --git a/ddl/label/attributes_test.go b/ddl/label/attributes_test.go
index 3198f98f523c3..38ea9f3e52ada 100644
--- a/ddl/label/attributes_test.go
+++ b/ddl/label/attributes_test.go
@@ -21,8 +21,6 @@ import (
 )
 
 func TestNewLabel(t *testing.T) {
-	t.Parallel()
-
 	type TestCase struct {
 		name  string
 		input string
@@ -58,8 +56,6 @@ func TestNewLabel(t *testing.T) {
 }
 
 func TestRestoreLabel(t *testing.T) {
-	t.Parallel()
-
 	type TestCase struct {
 		name   string
 		input  Label
@@ -94,8 +90,6 @@ func TestRestoreLabel(t *testing.T) {
 }
 
 func TestNewLabels(t *testing.T) {
-	t.Parallel()
-
 	labels, err := NewLabels(nil)
 	require.NoError(t, err)
 	require.Len(t, labels, 0)
@@ -128,8 +122,6 @@ func TestNewLabels(t *testing.T) {
 }
 
 func TestAddLabels(t *testing.T) {
-	t.Parallel()
-
 	type TestCase struct {
 		name   string
 		labels Labels
@@ -191,8 +183,6 @@ func TestAddLabels(t *testing.T) {
 }
 
 func TestRestoreLabels(t *testing.T) {
-	t.Parallel()
-
 	type TestCase struct {
 		name   string
 		input  Labels
diff --git a/ddl/label/rule_test.go b/ddl/label/rule_test.go
index 050635579c521..a0d3b02555e13 100644
--- a/ddl/label/rule_test.go
+++ b/ddl/label/rule_test.go
@@ -22,8 +22,6 @@ import (
 )
 
 func TestApplyAttributesSpec(t *testing.T) {
-	t.Parallel()
-
 	// valid case
 	spec := &ast.AttributesSpec{Attributes: "key=value,key1=value1"}
 	rule := NewRule()
@@ -51,8 +49,6 @@ func TestApplyAttributesSpec(t *testing.T) {
 }
 
 func TestDefaultOrEmpty(t *testing.T) {
-	t.Parallel()
-
 	specs := []*ast.AttributesSpec{{Attributes: ""}, {Default: true}}
 	for i := range specs {
 		rule := NewRule()
@@ -65,8 +61,6 @@ func TestDefaultOrEmpty(t *testing.T) {
 }
 
 func TestReset(t *testing.T) {
-	t.Parallel()
-
 	spec := &ast.AttributesSpec{Attributes: "key=value"}
 	rule := NewRule()
 	require.NoError(t, rule.ApplyAttributesSpec(spec))
diff --git a/ddl/options_test.go b/ddl/options_test.go
index a7d5e138c474a..1fe257072eaab 100644
--- a/ddl/options_test.go
+++ b/ddl/options_test.go
@@ -26,8 +26,6 @@ import (
 )
 
 func TestOptions(t *testing.T) {
-	t.Parallel()
-
 	client, err := clientv3.NewFromURL("test")
 	require.NoError(t, err)
 	callback := &ddl.BaseCallback{}
diff --git a/ddl/table_split_test.go b/ddl/table_split_test.go
index a7f7462a8400e..299abe09fb686 100644
--- a/ddl/table_split_test.go
+++ b/ddl/table_split_test.go
@@ -33,8 +33,6 @@ import (
 )
 
 func TestTableSplit(t *testing.T) {
-	t.Parallel()
-
 	store, err := mockstore.NewMockStore()
 	require.NoError(t, err)
 	defer func() {
diff --git a/distsql/distsql_test.go b/distsql/distsql_test.go
index 75a548c806ced..6ff4a5cb284e5 100644
--- a/distsql/distsql_test.go
+++ b/distsql/distsql_test.go
@@ -43,7 +43,6 @@ import (
 )
 
 func TestSelectNormal(t *testing.T) {
-	t.Parallel()
 	response, colTypes := createSelectNormal(t, 1, 2, nil, nil)
 
 	// Test Next.
@@ -63,7 +62,6 @@ func TestSelectNormal(t *testing.T) {
 }
 
 func TestSelectMemTracker(t *testing.T) {
-	t.Parallel()
 	response, colTypes := createSelectNormal(t, 2, 6, nil, nil)
 
 	// Test Next.
@@ -76,7 +74,6 @@ func TestSelectMemTracker(t *testing.T) {
 }
 
 func TestSelectNormalChunkSize(t *testing.T) {
-	t.Parallel()
 	sctx := newMockSessionContext()
 	sctx.GetSessionVars().EnableChunkRPC = false
 	response, colTypes := createSelectNormal(t, 100, 1000000, nil, sctx)
@@ -86,7 +83,6 @@ func TestSelectNormalChunkSize(t *testing.T) {
 }
 
 func TestSelectWithRuntimeStats(t *testing.T) {
-	t.Parallel()
 	planIDs := []int{1, 2, 3}
 	response, colTypes := createSelectNormal(t, 1, 2, planIDs, nil)
 
@@ -111,7 +107,6 @@ func TestSelectWithRuntimeStats(t *testing.T) {
 }
 
 func TestSelectResultRuntimeStats(t *testing.T) {
-	t.Parallel()
 	basic := &execdetails.BasicRuntimeStats{}
 	basic.Record(time.Second, 20)
 	s1 := &selectResultRuntimeStats{
@@ -158,7 +153,6 @@ func TestSelectResultRuntimeStats(t *testing.T) {
 }
 
 func TestSelectStreaming(t *testing.T) {
-	t.Parallel()
 	response, colTypes := createSelectStreaming(t, 1, 2)
 	// Test Next.
 	chk := chunk.New(colTypes, 32, 32)
@@ -176,7 +170,6 @@ func TestSelectStreaming(t *testing.T) {
 }
 
 func TestSelectStreamingWithNextRaw(t *testing.T) {
-	t.Parallel()
 	response, _ := createSelectStreaming(t, 1, 2)
 	data, err := response.NextRaw(context.TODO())
 	require.NoError(t, err)
@@ -184,14 +177,12 @@ func TestSelectStreamingWithNextRaw(t *testing.T) {
 }
 
 func TestSelectStreamingChunkSize(t *testing.T) {
-	t.Parallel()
 	response, colTypes := createSelectStreaming(t, 100, 1000000)
 	testChunkSize(t, response, colTypes)
 	require.NoError(t, response.Close())
 }
 
 func TestAnalyze(t *testing.T) {
-	t.Parallel()
 	sctx := newMockSessionContext()
 	sctx.GetSessionVars().EnableChunkRPC = false
 	request, err := (&RequestBuilder{}).SetKeyRanges(nil).
@@ -217,7 +208,6 @@ func TestAnalyze(t *testing.T) {
 }
 
 func TestChecksum(t *testing.T) {
-	t.Parallel()
 	sctx := newMockSessionContext()
 	sctx.GetSessionVars().EnableChunkRPC = false
 	request, err := (&RequestBuilder{}).SetKeyRanges(nil).
diff --git a/distsql/request_builder_test.go b/distsql/request_builder_test.go
index 3b9a7926e0fe1..1c0c99523344b 100644
--- a/distsql/request_builder_test.go
+++ b/distsql/request_builder_test.go
@@ -38,7 +38,6 @@ type handleRange struct {
 }
 
 func TestTableHandlesToKVRanges(t *testing.T) {
-	t.Parallel()
 	handles := []kv.Handle{
 		kv.IntHandle(0),
 		kv.IntHandle(2),
@@ -71,7 +70,6 @@ func TestTableHandlesToKVRanges(t *testing.T) {
 }
 
 func TestTableRangesToKVRanges(t *testing.T) {
-	t.Parallel()
 	ranges := []*ranger.Range{
 		{
 			LowVal:  []types.Datum{types.NewIntDatum(1)},
@@ -129,7 +127,6 @@ func TestTableRangesToKVRanges(t *testing.T) {
 }
 
 func TestIndexRangesToKVRanges(t *testing.T) {
-	t.Parallel()
 	ranges := []*ranger.Range{
 		{
 			LowVal:  []types.Datum{types.NewIntDatum(1)},
@@ -189,7 +186,6 @@ func TestIndexRangesToKVRanges(t *testing.T) {
 }
 
 func TestRequestBuilder1(t *testing.T) {
-	t.Parallel()
 	ranges := []*ranger.Range{
 		{
 			LowVal:  []types.Datum{types.NewIntDatum(1)},
@@ -267,7 +263,6 @@ func TestRequestBuilder1(t *testing.T) {
 }
 
 func TestRequestBuilder2(t *testing.T) {
-	t.Parallel()
 	ranges := []*ranger.Range{
 		{
 			LowVal:  []types.Datum{types.NewIntDatum(1)},
@@ -345,7 +340,6 @@ func TestRequestBuilder2(t *testing.T) {
 }
 
 func TestRequestBuilder3(t *testing.T) {
-	t.Parallel()
 	handles := []kv.Handle{kv.IntHandle(0), kv.IntHandle(2), kv.IntHandle(3), kv.IntHandle(4),
 		kv.IntHandle(5), kv.IntHandle(10), kv.IntHandle(11), kv.IntHandle(100)}
 
@@ -394,7 +388,6 @@ func TestRequestBuilder3(t *testing.T) {
 }
 
 func TestRequestBuilder4(t *testing.T) {
-	t.Parallel()
 	keyRanges := []kv.KeyRange{
 		{
 			StartKey: kv.Key{0x74, 0x80, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0xf, 0x5f, 0x72, 0x80, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0},
@@ -443,7 +436,6 @@ func TestRequestBuilder4(t *testing.T) {
 }
 
 func TestRequestBuilder5(t *testing.T) {
-	t.Parallel()
 	keyRanges := []kv.KeyRange{
 		{
 			StartKey: kv.Key{0x74, 0x80, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0xf, 0x5f, 0x72, 0x80, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0},
@@ -488,7 +480,6 @@ func TestRequestBuilder5(t *testing.T) {
 }
 
 func TestRequestBuilder6(t *testing.T) {
-	t.Parallel()
 	keyRanges := []kv.KeyRange{
 		{
 			StartKey: kv.Key{0x00, 0x01},
@@ -531,7 +522,6 @@ func TestRequestBuilder7(t *testing.T) {
 		// copy iterator variable into a new variable, see issue #27779
 		replicaRead := replicaRead
 		t.Run(replicaRead.src, func(t *testing.T) {
-			t.Parallel()
 			vars := variable.NewSessionVars()
 			vars.SetReplicaRead(replicaRead.replicaReadType)
 
@@ -561,7 +551,6 @@ func TestRequestBuilder7(t *testing.T) {
 }
 
 func TestRequestBuilder8(t *testing.T) {
-	t.Parallel()
 	sv := variable.NewSessionVars()
 	actual, err := (&RequestBuilder{}).
 		SetFromSessionVars(sv).
@@ -582,7 +571,6 @@ func TestRequestBuilder8(t *testing.T) {
 }
 
 func TestTableRangesToKVRangesWithFbs(t *testing.T) {
-	t.Parallel()
 	ranges := []*ranger.Range{
 		{
 			LowVal:  []types.Datum{types.NewIntDatum(1)},
@@ -604,7 +592,6 @@ func TestTableRangesToKVRangesWithFbs(t *testing.T) {
 }
 
 func TestIndexRangesToKVRangesWithFbs(t *testing.T) {
-	t.Parallel()
 	ranges := []*ranger.Range{
 		{
 			LowVal:  []types.Datum{types.NewIntDatum(1)},
@@ -641,7 +628,6 @@ func TestScanLimitConcurrency(t *testing.T) {
 		// copy iterator variable into a new variable, see issue #27779
 		tt := tt
 		t.Run(tt.src, func(t *testing.T) {
-			t.Parallel()
 			firstExec := &tipb.Executor{Tp: tt.tp}
 			switch tt.tp {
 			case tipb.ExecType_TypeTableScan:
diff --git a/distsql/select_result_test.go b/distsql/select_result_test.go
index 178d29bebeb22..622e672e1ee9d 100644
--- a/distsql/select_result_test.go
+++ b/distsql/select_result_test.go
@@ -29,8 +29,6 @@ import (
 )
 
 func TestUpdateCopRuntimeStats(t *testing.T) {
-	t.Parallel()
-
 	ctx := mock.NewContext()
 	ctx.GetSessionVars().StmtCtx = new(stmtctx.StatementContext)
 	sr := selectResult{ctx: ctx, storeType: kv.TiKV}
diff --git a/domain/domain_utils_test.go b/domain/domain_utils_test.go
index 6b5b9df0a1a47..6af9e1b3fc98a 100644
--- a/domain/domain_utils_test.go
+++ b/domain/domain_utils_test.go
@@ -23,12 +23,10 @@ import (
 )
 
 func TestErrorCode(t *testing.T) {
-	t.Parallel()
 	require.Equal(t, errno.ErrInfoSchemaExpired, int(terror.ToSQLError(ErrInfoSchemaExpired).Code))
 	require.Equal(t, errno.ErrInfoSchemaChanged, int(terror.ToSQLError(ErrInfoSchemaChanged).Code))
 }
 
 func TestServerIDConstant(t *testing.T) {
-	t.Parallel()
 	require.Less(t, lostConnectionToPDTimeout, serverIDTTL)
 }
diff --git a/domain/domainctx_test.go b/domain/domainctx_test.go
index 16f1dc5301b8a..b8d971b948ee4 100644
--- a/domain/domainctx_test.go
+++ b/domain/domainctx_test.go
@@ -22,8 +22,6 @@ import (
 )
 
 func TestDomainCtx(t *testing.T) {
-	t.Parallel()
-
 	ctx := mock.NewContext()
 	require.NotEqual(t, "", domainKey.String())
 
diff --git a/domain/main_test.go b/domain/main_test.go
index cfc42129ccafd..069ed9590f222 100644
--- a/domain/main_test.go
+++ b/domain/main_test.go
@@ -33,8 +33,6 @@ func TestMain(m *testing.M) {
 
 // TestDomainSerial handles tests in serial
 func TestDomainSerial(t *testing.T) {
-	t.Parallel()
-
 	// these tests should run in serial for failpoint is global
 	t.Run("info", SubTestInfo)
 	t.Run("domain", SubTestDomain)
diff --git a/domain/schema_checker_test.go b/domain/schema_checker_test.go
index bc3662dc37b2b..ee725ae4d5bbe 100644
--- a/domain/schema_checker_test.go
+++ b/domain/schema_checker_test.go
@@ -24,8 +24,6 @@ import (
 )
 
 func TestSchemaCheckerSimple(t *testing.T) {
-	t.Parallel()
-
 	lease := 5 * time.Millisecond
 	validator := NewSchemaValidator(lease, nil)
 	checker := &SchemaChecker{SchemaValidator: validator}
diff --git a/domain/schema_validator_test.go b/domain/schema_validator_test.go
index 4305ebbcd698f..2eb56d69e0cc1 100644
--- a/domain/schema_validator_test.go
+++ b/domain/schema_validator_test.go
@@ -27,7 +27,6 @@ import (
 )
 
 func TestSchemaValidator(t *testing.T) {
-	t.Parallel()
 	t.Run("general", subTestSchemaValidatorGeneral)
 	t.Run("enqueue", subTestEnqueue)
 	t.Run("enqueueActionType", subTestEnqueueActionType)
diff --git a/domain/session_pool_test.go b/domain/session_pool_test.go
index 5f3e97a07ed1e..ab20772aba935 100644
--- a/domain/session_pool_test.go
+++ b/domain/session_pool_test.go
@@ -22,8 +22,6 @@ import (
 )
 
 func TestSessionPool(t *testing.T) {
-	t.Parallel()
-
 	f := func() (pools.Resource, error) { return &testResource{}, nil }
 	pool := newSessionPool(1, f)
 	tr, err := pool.Get()
diff --git a/domain/topn_slow_query_test.go b/domain/topn_slow_query_test.go
index effbeddde34e5..7247234d2d42a 100644
--- a/domain/topn_slow_query_test.go
+++ b/domain/topn_slow_query_test.go
@@ -22,8 +22,6 @@ import (
 )
 
 func TestPush(t *testing.T) {
-	t.Parallel()
-
 	slowQuery := newTopNSlowQueries(10, 0, 10)
 	// Insert data into the heap.
 	slowQuery.Append(&SlowQueryInfo{Duration: 300 * time.Millisecond})
@@ -70,8 +68,6 @@ func TestPush(t *testing.T) {
 }
 
 func TestRemoveExpired(t *testing.T) {
-	t.Parallel()
-
 	now := time.Now()
 	slowQuery := newTopNSlowQueries(6, 3*time.Second, 10)
 
@@ -99,8 +95,6 @@ func TestRemoveExpired(t *testing.T) {
 }
 
 func TestQueue(t *testing.T) {
-	t.Parallel()
-
 	q := newTopNSlowQueries(10, time.Minute, 5)
 	q.Append(&SlowQueryInfo{SQL: "aaa"})
 	q.Append(&SlowQueryInfo{SQL: "bbb"})
diff --git a/dumpling/export/block_allow_list_test.go b/dumpling/export/block_allow_list_test.go
index 37f8c45f39c37..3ce55497d589b 100644
--- a/dumpling/export/block_allow_list_test.go
+++ b/dumpling/export/block_allow_list_test.go
@@ -15,8 +15,6 @@ import (
 )
 
 func TestFilterTables(t *testing.T) {
-	t.Parallel()
-
 	tctx := tcontext.Background().WithLogger(appLogger)
 	dbTables := DatabaseTables{}
 	expectedDBTables := DatabaseTables{}
@@ -49,8 +47,6 @@ func TestFilterTables(t *testing.T) {
 }
 
 func TestFilterDatabaseWithNoTable(t *testing.T) {
-	t.Parallel()
-
 	dbTables := DatabaseTables{}
 	expectedDBTables := DatabaseTables{}
 
diff --git a/dumpling/export/config_test.go b/dumpling/export/config_test.go
index fd6ed05885384..80c8046d1faa5 100644
--- a/dumpling/export/config_test.go
+++ b/dumpling/export/config_test.go
@@ -12,7 +12,6 @@ import (
 )
 
 func TestCreateExternalStorage(t *testing.T) {
-	t.Parallel()
 	mockConfig := defaultConfigForTest(t)
 	loc, err := mockConfig.createExternalStorage(tcontext.Background())
 	require.NoError(t, err)
@@ -20,7 +19,6 @@ func TestCreateExternalStorage(t *testing.T) {
 }
 
 func TestMatchMysqlBugVersion(t *testing.T) {
-	t.Parallel()
 	cases := []struct {
 		serverInfo version.ServerInfo
 		expected   bool
diff --git a/dumpling/export/consistency_test.go b/dumpling/export/consistency_test.go
index a71fea027a5c0..dbc47a7ed1723 100644
--- a/dumpling/export/consistency_test.go
+++ b/dumpling/export/consistency_test.go
@@ -18,8 +18,6 @@ import (
 )
 
 func TestConsistencyController(t *testing.T) {
-	t.Parallel()
-
 	db, mock, err := sqlmock.New()
 	require.NoError(t, err)
 	defer func() {
@@ -74,8 +72,6 @@ func TestConsistencyController(t *testing.T) {
 }
 
 func TestConsistencyLockControllerRetry(t *testing.T) {
-	t.Parallel()
-
 	db, mock, err := sqlmock.New()
 	require.NoError(t, err)
 	defer func() {
@@ -112,8 +108,6 @@ func TestConsistencyLockControllerRetry(t *testing.T) {
 }
 
 func TestResolveAutoConsistency(t *testing.T) {
-	t.Parallel()
-
 	conf := defaultConfigForTest(t)
 	cases := []struct {
 		serverTp            version.ServerType
@@ -135,8 +129,6 @@ func TestResolveAutoConsistency(t *testing.T) {
 }
 
 func TestConsistencyControllerError(t *testing.T) {
-	t.Parallel()
-
 	db, mock, err := sqlmock.New()
 	require.NoError(t, err)
 	defer func() {
@@ -176,8 +168,6 @@ func TestConsistencyControllerError(t *testing.T) {
 }
 
 func TestConsistencyLockTiDBCheck(t *testing.T) {
-	t.Parallel()
-
 	db, mock, err := sqlmock.New()
 	require.NoError(t, err)
 	defer func() {
diff --git a/dumpling/export/dump_test.go b/dumpling/export/dump_test.go
index 505fd04d20a39..0673e0588f3be 100644
--- a/dumpling/export/dump_test.go
+++ b/dumpling/export/dump_test.go
@@ -19,8 +19,6 @@ import (
 )
 
 func TestDumpBlock(t *testing.T) {
-	t.Parallel()
-
 	db, mock, err := sqlmock.New()
 	require.NoError(t, err)
 	defer func() {
@@ -65,8 +63,6 @@ func TestDumpBlock(t *testing.T) {
 }
 
 func TestDumpTableMeta(t *testing.T) {
-	t.Parallel()
-
 	db, mock, err := sqlmock.New()
 	require.NoError(t, err)
 	defer func() {
@@ -106,8 +102,6 @@ func TestDumpTableMeta(t *testing.T) {
 }
 
 func TestGetListTableTypeByConf(t *testing.T) {
-	t.Parallel()
-
 	conf := defaultConfigForTest(t)
 	cases := []struct {
 		serverInfo  version.ServerInfo
@@ -134,8 +128,6 @@ func TestGetListTableTypeByConf(t *testing.T) {
 }
 
 func TestAdjustDatabaseCollation(t *testing.T) {
-	t.Parallel()
-
 	tctx, cancel := tcontext.Background().WithLogger(appLogger).WithCancel()
 	defer cancel()
 	parser1 := parser.New()
@@ -158,8 +150,6 @@ func TestAdjustDatabaseCollation(t *testing.T) {
 }
 
 func TestAdjustTableCollation(t *testing.T) {
-	t.Parallel()
-
 	tctx, cancel := tcontext.Background().WithLogger(appLogger).WithCancel()
 	defer cancel()
 
diff --git a/dumpling/export/ir_impl_test.go b/dumpling/export/ir_impl_test.go
index 97a5a47dad304..2f8681b3c1363 100644
--- a/dumpling/export/ir_impl_test.go
+++ b/dumpling/export/ir_impl_test.go
@@ -25,8 +25,6 @@ func (s *simpleRowReceiver) BindAddress(args []interface{}) {
 }
 
 func TestRowIter(t *testing.T) {
-	t.Parallel()
-
 	db, mock, err := sqlmock.New()
 	require.NoError(t, err)
 	defer func() {
@@ -66,8 +64,6 @@ func TestRowIter(t *testing.T) {
 }
 
 func TestChunkRowIter(t *testing.T) {
-	t.Parallel()
-
 	db, mock, err := sqlmock.New()
 	require.NoError(t, err)
 	defer func() {
diff --git a/dumpling/export/metadata_test.go b/dumpling/export/metadata_test.go
index de477bc074845..dc67c73628b87 100644
--- a/dumpling/export/metadata_test.go
+++ b/dumpling/export/metadata_test.go
@@ -24,8 +24,6 @@ const (
 )
 
 func TestMysqlMetaData(t *testing.T) {
-	t.Parallel()
-
 	db, mock, err := sqlmock.New()
 	require.NoError(t, err)
 	defer func() {
@@ -54,8 +52,6 @@ func TestMysqlMetaData(t *testing.T) {
 }
 
 func TestMetaDataAfterConn(t *testing.T) {
-	t.Parallel()
-
 	db, mock, err := sqlmock.New()
 	require.NoError(t, err)
 	defer func() {
@@ -95,8 +91,6 @@ func TestMetaDataAfterConn(t *testing.T) {
 }
 
 func TestMysqlWithFollowersMetaData(t *testing.T) {
-	t.Parallel()
-
 	db, mock, err := sqlmock.New()
 	require.NoError(t, err)
 	defer func() {
@@ -131,8 +125,6 @@ func TestMysqlWithFollowersMetaData(t *testing.T) {
 }
 
 func TestMysqlWithNullFollowersMetaData(t *testing.T) {
-	t.Parallel()
-
 	db, mock, err := sqlmock.New()
 	require.NoError(t, err)
 	defer func() {
@@ -160,8 +152,6 @@ func TestMysqlWithNullFollowersMetaData(t *testing.T) {
 }
 
 func TestMariaDBMetaData(t *testing.T) {
-	t.Parallel()
-
 	db, mock, err := sqlmock.New()
 	require.NoError(t, err)
 	defer func() {
@@ -187,8 +177,6 @@ func TestMariaDBMetaData(t *testing.T) {
 }
 
 func TestMariaDBWithFollowersMetaData(t *testing.T) {
-	t.Parallel()
-
 	db, mock, err := sqlmock.New()
 	require.NoError(t, err)
 	defer func() {
@@ -233,8 +221,6 @@ func TestMariaDBWithFollowersMetaData(t *testing.T) {
 }
 
 func TestEarlierMysqlMetaData(t *testing.T) {
-	t.Parallel()
-
 	db, mock, err := sqlmock.New()
 	require.NoError(t, err)
 	defer func() {
@@ -265,8 +251,6 @@ func TestEarlierMysqlMetaData(t *testing.T) {
 }
 
 func TestTiDBSnapshotMetaData(t *testing.T) {
-	t.Parallel()
-
 	db, mock, err := sqlmock.New()
 	require.NoError(t, err)
 	defer func() {
@@ -307,8 +291,6 @@ func TestTiDBSnapshotMetaData(t *testing.T) {
 }
 
 func TestNoPrivilege(t *testing.T) {
-	t.Parallel()
-
 	db, mock, err := sqlmock.New()
 	require.NoError(t, err)
 	defer func() {
diff --git a/dumpling/export/prepare_test.go b/dumpling/export/prepare_test.go
index 4315024148518..79588de6e4c04 100644
--- a/dumpling/export/prepare_test.go
+++ b/dumpling/export/prepare_test.go
@@ -15,8 +15,6 @@ import (
 )
 
 func TestPrepareDumpingDatabases(t *testing.T) {
-	t.Parallel()
-
 	db, mock, err := sqlmock.New()
 	require.NoError(t, err)
 	defer func() {
@@ -65,8 +63,6 @@ func TestPrepareDumpingDatabases(t *testing.T) {
 }
 
 func TestListAllTables(t *testing.T) {
-	t.Parallel()
-
 	db, mock, err := sqlmock.New()
 	require.NoError(t, err)
 	defer func() {
@@ -129,8 +125,6 @@ func TestListAllTables(t *testing.T) {
 }
 
 func TestListAllTablesByTableStatus(t *testing.T) {
-	t.Parallel()
-
 	db, mock, err := sqlmock.New()
 	require.NoError(t, err)
 	defer func() {
@@ -197,8 +191,6 @@ func TestListAllTablesByTableStatus(t *testing.T) {
 }
 
 func TestListAllTablesByShowFullTables(t *testing.T) {
-	t.Parallel()
-
 	db, mock, err := sqlmock.New()
 	require.NoError(t, err)
 	defer func() {
@@ -274,8 +266,6 @@ func TestListAllTablesByShowFullTables(t *testing.T) {
 }
 
 func TestConfigValidation(t *testing.T) {
-	t.Parallel()
-
 	conf := defaultConfigForTest(t)
 	conf.Where = "id < 5"
 	conf.SQL = "select * from t where id > 3"
@@ -309,8 +299,6 @@ func TestConfigValidation(t *testing.T) {
 }
 
 func TestValidateResolveAutoConsistency(t *testing.T) {
-	t.Parallel()
-
 	conf1 := defaultConfigForTest(t)
 	d := &Dumper{conf: conf1}
 	conf := d.conf
diff --git a/dumpling/export/sql_test.go b/dumpling/export/sql_test.go
index 44ba39ec01d8c..4fd8cb31276b8 100644
--- a/dumpling/export/sql_test.go
+++ b/dumpling/export/sql_test.go
@@ -51,8 +51,6 @@ const (
 )
 
 func TestBuildSelectAllQuery(t *testing.T) {
-	t.Parallel()
-
 	db, mock, err := sqlmock.New()
 	require.NoError(t, err)
 	defer func() {
@@ -174,8 +172,6 @@ func TestBuildSelectAllQuery(t *testing.T) {
 }
 
 func TestBuildOrderByClause(t *testing.T) {
-	t.Parallel()
-
 	db, mock, err := sqlmock.New()
 	require.NoError(t, err)
 	defer func() {
@@ -238,8 +234,6 @@ func TestBuildOrderByClause(t *testing.T) {
 }
 
 func TestBuildSelectField(t *testing.T) {
-	t.Parallel()
-
 	db, mock, err := sqlmock.New()
 	require.NoError(t, err)
 	defer func() {
@@ -286,8 +280,6 @@ func TestBuildSelectField(t *testing.T) {
 }
 
 func TestParseSnapshotToTSO(t *testing.T) {
-	t.Parallel()
-
 	db, mock, err := sqlmock.New()
 	require.NoError(t, err)
 	defer func() {
@@ -316,8 +308,6 @@ func TestParseSnapshotToTSO(t *testing.T) {
 }
 
 func TestShowCreateView(t *testing.T) {
-	t.Parallel()
-
 	db, mock, err := sqlmock.New()
 	require.NoError(t, err)
 	defer func() {
@@ -343,8 +333,6 @@ func TestShowCreateView(t *testing.T) {
 }
 
 func TestShowCreatePolicy(t *testing.T) {
-	t.Parallel()
-
 	db, mock, err := sqlmock.New()
 	require.NoError(t, err)
 	defer func() {
@@ -366,8 +354,6 @@ func TestShowCreatePolicy(t *testing.T) {
 }
 
 func TestListPolicyNames(t *testing.T) {
-	t.Parallel()
-
 	db, mock, err := sqlmock.New()
 	require.NoError(t, err)
 	defer func() {
@@ -396,8 +382,6 @@ func TestListPolicyNames(t *testing.T) {
 }
 
 func TestGetSuitableRows(t *testing.T) {
-	t.Parallel()
-
 	testCases := []struct {
 		avgRowLength uint64
 		expectedRows uint64
@@ -426,8 +410,6 @@ func TestGetSuitableRows(t *testing.T) {
 }
 
 func TestSelectTiDBRowID(t *testing.T) {
-	t.Parallel()
-
 	db, mock, err := sqlmock.New()
 	require.NoError(t, err)
 	defer func() {
@@ -463,8 +445,6 @@ func TestSelectTiDBRowID(t *testing.T) {
 }
 
 func TestBuildTableSampleQueries(t *testing.T) {
-	t.Parallel()
-
 	db, mock, err := sqlmock.New()
 	require.NoError(t, err)
 	defer func() {
@@ -782,8 +762,6 @@ func TestBuildTableSampleQueries(t *testing.T) {
 }
 
 func TestBuildPartitionClauses(t *testing.T) {
-	t.Parallel()
-
 	const (
 		dbName        = "test"
 		tbName        = "t"
@@ -842,8 +820,6 @@ func TestBuildPartitionClauses(t *testing.T) {
 }
 
 func TestBuildWhereCondition(t *testing.T) {
-	t.Parallel()
-
 	conf := DefaultConfig()
 	testCases := []struct {
 		confWhere     string
@@ -879,8 +855,6 @@ func TestBuildWhereCondition(t *testing.T) {
 }
 
 func TestBuildRegionQueriesWithoutPartition(t *testing.T) {
-	t.Parallel()
-
 	db, mock, err := sqlmock.New()
 	require.NoError(t, err)
 	defer func() {
@@ -1040,8 +1014,6 @@ func TestBuildRegionQueriesWithoutPartition(t *testing.T) {
 }
 
 func TestBuildRegionQueriesWithPartitions(t *testing.T) {
-	t.Parallel()
-
 	db, mock, err := sqlmock.New()
 	require.NoError(t, err)
 	defer func() {
@@ -1277,8 +1249,6 @@ func readRegionCsvDriverValues(t *testing.T) [][]driver.Value {
 }
 
 func TestBuildVersion3RegionQueries(t *testing.T) {
-	t.Parallel()
-
 	db, mock, err := sqlmock.New()
 	require.NoError(t, err)
 	defer func() {
@@ -1554,8 +1524,6 @@ func TestBuildVersion3RegionQueries(t *testing.T) {
 }
 
 func TestCheckTiDBWithTiKV(t *testing.T) {
-	t.Parallel()
-
 	db, mock, err := sqlmock.New()
 	require.NoError(t, err)
 	defer func() {
@@ -1603,8 +1571,6 @@ func TestCheckTiDBWithTiKV(t *testing.T) {
 }
 
 func TestPickupPossibleField(t *testing.T) {
-	t.Parallel()
-
 	db, mock, err := sqlmock.New()
 	require.NoError(t, err)
 	defer func() {
@@ -1748,8 +1714,6 @@ func TestPickupPossibleField(t *testing.T) {
 }
 
 func TestCheckIfSeqExists(t *testing.T) {
-	t.Parallel()
-
 	db, mock, err := sqlmock.New()
 	require.NoError(t, err)
 	defer func() {
@@ -1777,7 +1741,6 @@ func TestCheckIfSeqExists(t *testing.T) {
 }
 
 func TestGetCharsetAndDefaultCollation(t *testing.T) {
-	t.Parallel()
 	db, mock, err := sqlmock.New()
 	require.NoError(t, err)
 	defer func() {
diff --git a/dumpling/export/sql_type_test.go b/dumpling/export/sql_type_test.go
index 97ae6d058123f..1ed75a3247472 100644
--- a/dumpling/export/sql_type_test.go
+++ b/dumpling/export/sql_type_test.go
@@ -10,8 +10,6 @@ import (
 )
 
 func TestEscape(t *testing.T) {
-	t.Parallel()
-
 	var bf bytes.Buffer
 	str := []byte(`MWQeWw""'\rNmtGxzGp`)
 	expectStrBackslash := `MWQeWw\"\"\'\\rNmtGxzGp`
diff --git a/dumpling/export/util_test.go b/dumpling/export/util_test.go
index 074f3c0a747da..c1da95155898e 100644
--- a/dumpling/export/util_test.go
+++ b/dumpling/export/util_test.go
@@ -11,8 +11,6 @@ import (
 )
 
 func TestRepeatableRead(t *testing.T) {
-	t.Parallel()
-
 	data := [][]interface{}{
 		{version.ServerTypeUnknown, consistencyTypeNone, true},
 		{version.ServerTypeMySQL, consistencyTypeFlush, true},
diff --git a/dumpling/export/writer_test.go b/dumpling/export/writer_test.go
index f7ff14993212e..9c577e8ab848a 100644
--- a/dumpling/export/writer_test.go
+++ b/dumpling/export/writer_test.go
@@ -18,8 +18,6 @@ import (
 )
 
 func TestWriteDatabaseMeta(t *testing.T) {
-	t.Parallel()
-
 	dir := t.TempDir()
 	config := defaultConfigForTest(t)
 	config.OutputDirPath = dir
@@ -40,8 +38,6 @@ func TestWriteDatabaseMeta(t *testing.T) {
 }
 
 func TestWritePolicyMeta(t *testing.T) {
-	t.Parallel()
-
 	dir := t.TempDir()
 	config := defaultConfigForTest(t)
 	config.OutputDirPath = dir
@@ -62,8 +58,6 @@ func TestWritePolicyMeta(t *testing.T) {
 }
 
 func TestWriteTableMeta(t *testing.T) {
-	t.Parallel()
-
 	dir := t.TempDir()
 
 	config := defaultConfigForTest(t)
@@ -83,8 +77,6 @@ func TestWriteTableMeta(t *testing.T) {
 }
 
 func TestWriteViewMeta(t *testing.T) {
-	t.Parallel()
-
 	dir := t.TempDir()
 	config := defaultConfigForTest(t)
 	config.OutputDirPath = dir
@@ -114,8 +106,6 @@ func TestWriteViewMeta(t *testing.T) {
 }
 
 func TestWriteTableData(t *testing.T) {
-	t.Parallel()
-
 	dir := t.TempDir()
 	config := defaultConfigForTest(t)
 	config.OutputDirPath = dir
@@ -155,8 +145,6 @@ func TestWriteTableData(t *testing.T) {
 }
 
 func TestWriteTableDataWithFileSize(t *testing.T) {
-	t.Parallel()
-
 	dir := t.TempDir()
 	config := defaultConfigForTest(t)
 	config.OutputDirPath = dir
@@ -207,8 +195,6 @@ func TestWriteTableDataWithFileSize(t *testing.T) {
 }
 
 func TestWriteTableDataWithFileSizeAndRows(t *testing.T) {
-	t.Parallel()
-
 	dir := t.TempDir()
 	config := defaultConfigForTest(t)
 	config.OutputDirPath = dir
@@ -260,8 +246,6 @@ func TestWriteTableDataWithFileSizeAndRows(t *testing.T) {
 }
 
 func TestWriteTableDataWithStatementSize(t *testing.T) {
-	t.Parallel()
-
 	dir := t.TempDir()
 	config := defaultConfigForTest(t)
 	config.OutputDirPath = dir
diff --git a/errno/infoschema_test.go b/errno/infoschema_test.go
index 063cd39072031..3878f57b90ddf 100644
--- a/errno/infoschema_test.go
+++ b/errno/infoschema_test.go
@@ -21,8 +21,6 @@ import (
 )
 
 func TestCopySafety(t *testing.T) {
-	t.Parallel()
-
 	IncrementError(123, "user", "host")
 	IncrementError(321, "user2", "host2")
 	IncrementWarning(123, "user", "host")
diff --git a/executor/adapter_test.go b/executor/adapter_test.go
index 40ae6e168b1f0..aea11b207baac 100644
--- a/executor/adapter_test.go
+++ b/executor/adapter_test.go
@@ -23,7 +23,6 @@ import (
 )
 
 func TestQueryTime(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
diff --git a/executor/admin_test.go b/executor/admin_test.go
index e984177ab4c52..2257060782b41 100644
--- a/executor/admin_test.go
+++ b/executor/admin_test.go
@@ -36,8 +36,6 @@ import (
 )
 
 func TestAdminCheckIndexRange(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -58,8 +56,6 @@ func TestAdminCheckIndexRange(t *testing.T) {
 }
 
 func TestAdminCheckIndex(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -89,8 +85,6 @@ func TestAdminCheckIndex(t *testing.T) {
 }
 
 func TestAdminCheckIndexInTemporaryMode(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -123,8 +117,6 @@ func TestAdminCheckIndexInTemporaryMode(t *testing.T) {
 }
 
 func TestAdminCheckIndexInLocalTemporaryMode(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -149,8 +141,6 @@ func TestAdminCheckIndexInLocalTemporaryMode(t *testing.T) {
 }
 
 func TestAdminCheckIndexInCacheTable(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -186,8 +176,6 @@ func TestAdminCheckIndexInCacheTable(t *testing.T) {
 	tk.MustExec("drop table if exists cache_admin_table_with_index_test,cache_admin_table_without_index_test;")
 }
 func TestAdminRecoverIndex(t *testing.T) {
-	t.Parallel()
-
 	store, domain, clean := testkit.CreateMockStoreAndDomain(t)
 	defer clean()
 
@@ -305,8 +293,6 @@ func TestAdminRecoverIndex(t *testing.T) {
 }
 
 func TestClusteredIndexAdminRecoverIndex(t *testing.T) {
-	t.Parallel()
-
 	store, domain, clean := testkit.CreateMockStoreAndDomain(t)
 	defer clean()
 
@@ -353,8 +339,6 @@ func TestClusteredIndexAdminRecoverIndex(t *testing.T) {
 }
 
 func TestAdminRecoverPartitionTableIndex(t *testing.T) {
-	t.Parallel()
-
 	store, domain, clean := testkit.CreateMockStoreAndDomain(t)
 	defer clean()
 
@@ -428,8 +412,6 @@ func TestAdminRecoverPartitionTableIndex(t *testing.T) {
 }
 
 func TestAdminRecoverIndex1(t *testing.T) {
-	t.Parallel()
-
 	store, domain, clean := testkit.CreateMockStoreAndDomain(t)
 	defer clean()
 
@@ -485,8 +467,6 @@ func TestAdminRecoverIndex1(t *testing.T) {
 }
 
 func TestAdminCleanupIndex(t *testing.T) {
-	t.Parallel()
-
 	store, domain, clean := testkit.CreateMockStoreAndDomain(t)
 	defer clean()
 
@@ -569,8 +549,6 @@ func TestAdminCleanupIndex(t *testing.T) {
 }
 
 func TestAdminCleanupIndexForPartitionTable(t *testing.T) {
-	t.Parallel()
-
 	store, domain, clean := testkit.CreateMockStoreAndDomain(t)
 	defer clean()
 
@@ -654,8 +632,6 @@ func TestAdminCleanupIndexForPartitionTable(t *testing.T) {
 }
 
 func TestAdminCleanupIndexPKNotHandle(t *testing.T) {
-	t.Parallel()
-
 	store, domain, clean := testkit.CreateMockStoreAndDomain(t)
 	defer clean()
 
@@ -708,8 +684,6 @@ func TestAdminCleanupIndexPKNotHandle(t *testing.T) {
 }
 
 func TestAdminCleanupIndexMore(t *testing.T) {
-	t.Parallel()
-
 	store, domain, clean := testkit.CreateMockStoreAndDomain(t)
 	defer clean()
 
@@ -776,8 +750,6 @@ func TestAdminCleanupIndexMore(t *testing.T) {
 }
 
 func TestClusteredAdminCleanupIndex(t *testing.T) {
-	t.Parallel()
-
 	store, domain, clean := testkit.CreateMockStoreAndDomain(t)
 	defer clean()
 
@@ -857,8 +829,6 @@ func TestClusteredAdminCleanupIndex(t *testing.T) {
 }
 
 func TestAdminCheckPartitionTableFailed(t *testing.T) {
-	t.Parallel()
-
 	store, domain, clean := testkit.CreateMockStoreAndDomain(t)
 	defer clean()
 
@@ -960,8 +930,6 @@ func TestAdminCheckPartitionTableFailed(t *testing.T) {
 
 func TestAdminCheckTable(t *testing.T) {
 	// test NULL value.
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -1081,8 +1049,6 @@ func TestAdminCheckTable(t *testing.T) {
 }
 
 func TestAdminCheckPrimaryIndex(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -1094,8 +1060,6 @@ func TestAdminCheckPrimaryIndex(t *testing.T) {
 }
 
 func TestAdminCheckWithSnapshot(t *testing.T) {
-	t.Parallel()
-
 	store, domain, clean := testkit.CreateMockStoreAndDomain(t)
 	defer clean()
 
diff --git a/executor/aggfuncs/func_avg_test.go b/executor/aggfuncs/func_avg_test.go
index 3e70460cc181d..28fbb0095ecc8 100644
--- a/executor/aggfuncs/func_avg_test.go
+++ b/executor/aggfuncs/func_avg_test.go
@@ -25,8 +25,6 @@ import (
 )
 
 func TestMergePartialResult4Avg(t *testing.T) {
-	t.Parallel()
-
 	tests := []aggTest{
 		buildAggTester(ast.AggFuncAvg, mysql.TypeNewDecimal, 5, 2.0, 3.0, 2.375),
 		buildAggTester(ast.AggFuncAvg, mysql.TypeDouble, 5, 2.0, 3.0, 2.375),
@@ -37,8 +35,6 @@ func TestMergePartialResult4Avg(t *testing.T) {
 }
 
 func TestAvg(t *testing.T) {
-	t.Parallel()
-
 	tests := []aggTest{
 		buildAggTester(ast.AggFuncAvg, mysql.TypeNewDecimal, 5, nil, 2.0),
 		buildAggTester(ast.AggFuncAvg, mysql.TypeDouble, 5, nil, 2.0),
@@ -50,8 +46,6 @@ func TestAvg(t *testing.T) {
 }
 
 func TestMemAvg(t *testing.T) {
-	t.Parallel()
-
 	tests := []aggMemTest{
 		buildAggMemTester(ast.AggFuncAvg, mysql.TypeNewDecimal, 5,
 			aggfuncs.DefPartialResult4AvgDecimalSize, defaultUpdateMemDeltaGens, false),
diff --git a/executor/aggfuncs/func_bitfuncs_test.go b/executor/aggfuncs/func_bitfuncs_test.go
index 7560c43e80e6a..d4a442c1a61e0 100644
--- a/executor/aggfuncs/func_bitfuncs_test.go
+++ b/executor/aggfuncs/func_bitfuncs_test.go
@@ -23,8 +23,6 @@ import (
 )
 
 func TestMergePartialResult4BitFuncs(t *testing.T) {
-	t.Parallel()
-
 	tests := []aggTest{
 		buildAggTester(ast.AggFuncBitAnd, mysql.TypeLonglong, 5, 0, 0, 0),
 		buildAggTester(ast.AggFuncBitOr, mysql.TypeLonglong, 5, 7, 7, 7),
@@ -36,8 +34,6 @@ func TestMergePartialResult4BitFuncs(t *testing.T) {
 }
 
 func TestMemBitFunc(t *testing.T) {
-	t.Parallel()
-
 	tests := []aggMemTest{
 		buildAggMemTester(ast.AggFuncBitAnd, mysql.TypeLonglong, 5,
 			aggfuncs.DefPartialResult4BitFuncSize, defaultUpdateMemDeltaGens, false),
diff --git a/executor/aggfuncs/func_count_test.go b/executor/aggfuncs/func_count_test.go
index e97960f4a8cba..b6bbfcfae8151 100644
--- a/executor/aggfuncs/func_count_test.go
+++ b/executor/aggfuncs/func_count_test.go
@@ -42,8 +42,6 @@ func genApproxDistinctMergePartialResult(begin, end uint64) string {
 }
 
 func TestMergePartialResult4Count(t *testing.T) {
-	t.Parallel()
-
 	tester := buildAggTester(ast.AggFuncCount, mysql.TypeLonglong, 5, 5, 3, 8)
 	testMergePartialResult(t, tester)
 
@@ -52,8 +50,6 @@ func TestMergePartialResult4Count(t *testing.T) {
 }
 
 func TestCount(t *testing.T) {
-	t.Parallel()
-
 	tests := []aggTest{
 		buildAggTester(ast.AggFuncCount, mysql.TypeLonglong, 5, 0, 5),
 		buildAggTester(ast.AggFuncCount, mysql.TypeFloat, 5, 0, 5),
@@ -118,8 +114,6 @@ func TestCount(t *testing.T) {
 }
 
 func TestMemCount(t *testing.T) {
-	t.Parallel()
-
 	tests := []aggMemTest{
 		buildAggMemTester(ast.AggFuncCount, mysql.TypeLonglong, 5,
 			aggfuncs.DefPartialResult4CountSize, defaultUpdateMemDeltaGens, false),
@@ -164,8 +158,6 @@ func TestMemCount(t *testing.T) {
 }
 
 func TestWriteTime(t *testing.T) {
-	t.Parallel()
-
 	tt, err := types.ParseDate(&(stmtctx.StatementContext{}), "2020-11-11")
 	require.NoError(t, err)
 
diff --git a/executor/aggfuncs/func_cume_dist_test.go b/executor/aggfuncs/func_cume_dist_test.go
index a68591682317f..77997453f5a23 100644
--- a/executor/aggfuncs/func_cume_dist_test.go
+++ b/executor/aggfuncs/func_cume_dist_test.go
@@ -23,8 +23,6 @@ import (
 )
 
 func TestMemCumeDist(t *testing.T) {
-	t.Parallel()
-
 	tests := []windowMemTest{
 		buildWindowMemTester(ast.WindowFuncCumeDist, mysql.TypeLonglong, 0, 1, 1,
 			aggfuncs.DefPartialResult4CumeDistSize, rowMemDeltaGens),
diff --git a/executor/aggfuncs/func_first_row_test.go b/executor/aggfuncs/func_first_row_test.go
index 1967bb0da3a95..2e75edd59e874 100644
--- a/executor/aggfuncs/func_first_row_test.go
+++ b/executor/aggfuncs/func_first_row_test.go
@@ -27,8 +27,6 @@ import (
 )
 
 func TestMergePartialResult4FirstRow(t *testing.T) {
-	t.Parallel()
-
 	elems := []string{"e", "d", "c", "b", "a"}
 	enumC, _ := types.ParseEnumName(elems, "c", mysql.DefaultCollationName)
 	enumE, _ := types.ParseEnumName(elems, "e", mysql.DefaultCollationName)
@@ -54,8 +52,6 @@ func TestMergePartialResult4FirstRow(t *testing.T) {
 }
 
 func TestMemFirstRow(t *testing.T) {
-	t.Parallel()
-
 	tests := []aggMemTest{
 		buildAggMemTester(ast.AggFuncFirstRow, mysql.TypeLonglong, 5,
 			aggfuncs.DefPartialResult4FirstRowIntSize, defaultUpdateMemDeltaGens, false),
diff --git a/executor/aggfuncs/func_group_concat_test.go b/executor/aggfuncs/func_group_concat_test.go
index f609de53f858e..eef46c1260e27 100644
--- a/executor/aggfuncs/func_group_concat_test.go
+++ b/executor/aggfuncs/func_group_concat_test.go
@@ -34,15 +34,11 @@ import (
 )
 
 func TestMergePartialResult4GroupConcat(t *testing.T) {
-	t.Parallel()
-
 	test := buildAggTester(ast.AggFuncGroupConcat, mysql.TypeString, 5, "0 1 2 3 4", "2 3 4", "0 1 2 3 4 2 3 4")
 	testMergePartialResult(t, test)
 }
 
 func TestGroupConcat(t *testing.T) {
-	t.Parallel()
-
 	ctx := mock.NewContext()
 
 	test := buildAggTester(ast.AggFuncGroupConcat, mysql.TypeString, 5, nil, "0 1 2 3 4")
@@ -67,8 +63,6 @@ func TestGroupConcat(t *testing.T) {
 }
 
 func TestMemGroupConcat(t *testing.T) {
-	t.Parallel()
-
 	multiArgsTest1 := buildMultiArgsAggMemTester(ast.AggFuncGroupConcat, []byte{mysql.TypeString, mysql.TypeString}, mysql.TypeString, 5,
 		aggfuncs.DefPartialResult4GroupConcatSize+aggfuncs.DefBytesBufferSize, groupConcatMultiArgsUpdateMemDeltaGens, false)
 	multiArgsTest2 := buildMultiArgsAggMemTester(ast.AggFuncGroupConcat, []byte{mysql.TypeString, mysql.TypeString}, mysql.TypeString, 5,
diff --git a/executor/aggfuncs/func_json_arrayagg_test.go b/executor/aggfuncs/func_json_arrayagg_test.go
index 46511bfb8a4ae..6f9ff09f9ed81 100644
--- a/executor/aggfuncs/func_json_arrayagg_test.go
+++ b/executor/aggfuncs/func_json_arrayagg_test.go
@@ -27,8 +27,6 @@ import (
 )
 
 func TestMergePartialResult4JsonArrayagg(t *testing.T) {
-	t.Parallel()
-
 	typeList := []byte{mysql.TypeLonglong, mysql.TypeDouble, mysql.TypeString, mysql.TypeJSON}
 
 	var tests []aggTest
@@ -66,8 +64,6 @@ func TestMergePartialResult4JsonArrayagg(t *testing.T) {
 }
 
 func TestJsonArrayagg(t *testing.T) {
-	t.Parallel()
-
 	typeList := []byte{mysql.TypeLonglong, mysql.TypeDouble, mysql.TypeString, mysql.TypeJSON}
 
 	var tests []aggTest
@@ -131,8 +127,6 @@ func jsonArrayaggMemDeltaGens(srcChk *chunk.Chunk, dataType *types.FieldType) (m
 }
 
 func TestMemJsonArrayagg(t *testing.T) {
-	t.Parallel()
-
 	typeList := []byte{mysql.TypeLonglong, mysql.TypeDouble, mysql.TypeString, mysql.TypeJSON}
 
 	var tests []aggMemTest
diff --git a/executor/aggfuncs/func_json_objectagg_test.go b/executor/aggfuncs/func_json_objectagg_test.go
index af27222f1506e..fd8897773099a 100644
--- a/executor/aggfuncs/func_json_objectagg_test.go
+++ b/executor/aggfuncs/func_json_objectagg_test.go
@@ -26,7 +26,6 @@ import (
 )
 
 func TestMergePartialResult4JsonObjectagg(t *testing.T) {
-	t.Parallel()
 	typeList := []byte{mysql.TypeLonglong, mysql.TypeDouble, mysql.TypeString, mysql.TypeJSON}
 	var argCombines [][]byte
 	for i := 0; i < len(typeList); i++ {
@@ -73,7 +72,6 @@ func TestMergePartialResult4JsonObjectagg(t *testing.T) {
 }
 
 func TestJsonObjectagg(t *testing.T) {
-	t.Parallel()
 	typeList := []byte{mysql.TypeLonglong, mysql.TypeDouble, mysql.TypeString, mysql.TypeJSON}
 	var argCombines [][]byte
 	for i := 0; i < len(typeList); i++ {
@@ -112,7 +110,6 @@ func TestJsonObjectagg(t *testing.T) {
 }
 
 func TestMemJsonObjectagg(t *testing.T) {
-	t.Parallel()
 	typeList := []byte{mysql.TypeLonglong, mysql.TypeDouble, mysql.TypeString, mysql.TypeJSON, mysql.TypeDuration, mysql.TypeNewDecimal, mysql.TypeDate}
 	var argCombines [][]byte
 	for i := 0; i < len(typeList); i++ {
diff --git a/executor/aggfuncs/func_lead_lag_test.go b/executor/aggfuncs/func_lead_lag_test.go
index 942b61ec131d9..279f1360eca74 100644
--- a/executor/aggfuncs/func_lead_lag_test.go
+++ b/executor/aggfuncs/func_lead_lag_test.go
@@ -25,8 +25,6 @@ import (
 )
 
 func TestLeadLag(t *testing.T) {
-	t.Parallel()
-
 	zero := expression.NewZero()
 	one := expression.NewOne()
 	two := &expression.Constant{
@@ -120,8 +118,6 @@ func TestLeadLag(t *testing.T) {
 }
 
 func TestMemLeadLag(t *testing.T) {
-	t.Parallel()
-
 	zero := expression.NewZero()
 	one := expression.NewOne()
 	two := &expression.Constant{
diff --git a/executor/aggfuncs/func_max_min_test.go b/executor/aggfuncs/func_max_min_test.go
index b33c72de903cd..fea0e78d5f5ef 100644
--- a/executor/aggfuncs/func_max_min_test.go
+++ b/executor/aggfuncs/func_max_min_test.go
@@ -95,8 +95,6 @@ func minUpdateMemDeltaGens(srcChk *chunk.Chunk, dataType *types.FieldType) (memD
 }
 
 func TestMergePartialResult4MaxMin(t *testing.T) {
-	t.Parallel()
-
 	elems := []string{"e", "d", "c", "b", "a"}
 	enumA, _ := types.ParseEnum(elems, "a", mysql.DefaultCollationName)
 	enumC, _ := types.ParseEnum(elems, "c", mysql.DefaultCollationName)
@@ -135,15 +133,12 @@ func TestMergePartialResult4MaxMin(t *testing.T) {
 	for _, test := range tests {
 		test := test
 		t.Run(test.funcName, func(t *testing.T) {
-			t.Parallel()
 			testMergePartialResult(t, test)
 		})
 	}
 }
 
 func TestMaxMin(t *testing.T) {
-	t.Parallel()
-
 	unsignedType := types.NewFieldType(mysql.TypeLonglong)
 	unsignedType.Flag |= mysql.UnsignedFlag
 	tests := []aggTest{
@@ -170,15 +165,12 @@ func TestMaxMin(t *testing.T) {
 	for _, test := range tests {
 		test := test
 		t.Run(test.funcName, func(t *testing.T) {
-			t.Parallel()
 			testAggFunc(t, test)
 		})
 	}
 }
 
 func TestMemMaxMin(t *testing.T) {
-	t.Parallel()
-
 	tests := []aggMemTest{
 		buildAggMemTester(ast.AggFuncMax, mysql.TypeLonglong, 5,
 			aggfuncs.DefPartialResult4MaxMinIntSize, defaultUpdateMemDeltaGens, false),
@@ -229,7 +221,6 @@ func TestMemMaxMin(t *testing.T) {
 	for _, test := range tests {
 		test := test
 		t.Run(test.aggTest.funcName, func(t *testing.T) {
-			t.Parallel()
 			testAggMemFunc(t, test)
 		})
 	}
@@ -268,8 +259,6 @@ func testMaxSlidingWindow(tk *testkit.TestKit, tc maxSlidingWindowTestCase) {
 }
 
 func TestMaxSlidingWindow(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 	tk := testkit.NewTestKit(t, store)
@@ -348,8 +337,6 @@ func TestMaxSlidingWindow(t *testing.T) {
 }
 
 func TestDequeReset(t *testing.T) {
-	t.Parallel()
-
 	deque := aggfuncs.NewDeque(true, func(i, j interface{}) int {
 		return types.CompareInt64(i.(int64), j.(int64))
 	})
@@ -360,8 +347,6 @@ func TestDequeReset(t *testing.T) {
 }
 
 func TestDequePushPop(t *testing.T) {
-	t.Parallel()
-
 	deque := aggfuncs.NewDeque(true, func(i, j interface{}) int {
 		return types.CompareInt64(i.(int64), j.(int64))
 	})
diff --git a/executor/aggfuncs/func_ntile_test.go b/executor/aggfuncs/func_ntile_test.go
index 723a3c44f7da3..5ec251d3a6bac 100644
--- a/executor/aggfuncs/func_ntile_test.go
+++ b/executor/aggfuncs/func_ntile_test.go
@@ -23,8 +23,6 @@ import (
 )
 
 func TestMemNtile(t *testing.T) {
-	t.Parallel()
-
 	tests := []windowMemTest{
 		buildWindowMemTester(ast.WindowFuncNtile, mysql.TypeLonglong, 1, 1, 1,
 			aggfuncs.DefPartialResult4Ntile, defaultUpdateMemDeltaGens),
diff --git a/executor/aggfuncs/func_percent_rank_test.go b/executor/aggfuncs/func_percent_rank_test.go
index 528d726cfe728..25d8bbef73712 100644
--- a/executor/aggfuncs/func_percent_rank_test.go
+++ b/executor/aggfuncs/func_percent_rank_test.go
@@ -23,8 +23,6 @@ import (
 )
 
 func TestMemPercentRank(t *testing.T) {
-	t.Parallel()
-
 	tests := []windowMemTest{
 		buildWindowMemTester(ast.WindowFuncPercentRank, mysql.TypeLonglong, 0, 1, 1,
 			aggfuncs.DefPartialResult4RankSize, rowMemDeltaGens),
diff --git a/executor/aggfuncs/func_percentile_test.go b/executor/aggfuncs/func_percentile_test.go
index a114ad1545f9b..dff7c4b6dfaf0 100644
--- a/executor/aggfuncs/func_percentile_test.go
+++ b/executor/aggfuncs/func_percentile_test.go
@@ -33,8 +33,6 @@ func (a testSlice) Swap(i, j int)      { a[i], a[j] = a[j], a[i] }
 func (a testSlice) Less(i, j int) bool { return a[i] < a[j] }
 
 func TestPercentile(t *testing.T) {
-	t.Parallel()
-
 	tests := []aggTest{
 		buildAggTester(ast.AggFuncApproxPercentile, mysql.TypeLonglong, 5, nil, 2),
 		buildAggTester(ast.AggFuncApproxPercentile, mysql.TypeFloat, 5, nil, 2.0),
diff --git a/executor/aggfuncs/func_rank_test.go b/executor/aggfuncs/func_rank_test.go
index db1c9ae140367..050069a0d31bc 100644
--- a/executor/aggfuncs/func_rank_test.go
+++ b/executor/aggfuncs/func_rank_test.go
@@ -23,8 +23,6 @@ import (
 )
 
 func TestMemRank(t *testing.T) {
-	t.Parallel()
-
 	tests := []windowMemTest{
 		buildWindowMemTester(ast.WindowFuncRank, mysql.TypeLonglong, 0, 1, 1,
 			aggfuncs.DefPartialResult4RankSize, rowMemDeltaGens),
diff --git a/executor/aggfuncs/func_stddevpop_test.go b/executor/aggfuncs/func_stddevpop_test.go
index 3dc95820351cd..e9b08422a0a39 100644
--- a/executor/aggfuncs/func_stddevpop_test.go
+++ b/executor/aggfuncs/func_stddevpop_test.go
@@ -22,8 +22,6 @@ import (
 )
 
 func TestMergePartialResult4Stddevpop(t *testing.T) {
-	t.Parallel()
-
 	tests := []aggTest{
 		buildAggTester(ast.AggFuncStddevPop, mysql.TypeDouble, 5, 1.4142135623730951, 0.816496580927726, 1.3169567191065923),
 	}
@@ -33,8 +31,6 @@ func TestMergePartialResult4Stddevpop(t *testing.T) {
 }
 
 func TestStddevpop(t *testing.T) {
-	t.Parallel()
-
 	tests := []aggTest{
 		buildAggTester(ast.AggFuncStddevPop, mysql.TypeDouble, 5, nil, 1.4142135623730951),
 	}
diff --git a/executor/aggfuncs/func_stddevsamp_test.go b/executor/aggfuncs/func_stddevsamp_test.go
index dc0f972c30712..d896fa640b5b5 100644
--- a/executor/aggfuncs/func_stddevsamp_test.go
+++ b/executor/aggfuncs/func_stddevsamp_test.go
@@ -22,8 +22,6 @@ import (
 )
 
 func TestMergePartialResult4Stddevsamp(t *testing.T) {
-	t.Parallel()
-
 	tests := []aggTest{
 		buildAggTester(ast.AggFuncStddevSamp, mysql.TypeDouble, 5, 1.5811388300841898, 1, 1.407885953173359),
 	}
@@ -33,8 +31,6 @@ func TestMergePartialResult4Stddevsamp(t *testing.T) {
 }
 
 func TestStddevsamp(t *testing.T) {
-	t.Parallel()
-
 	tests := []aggTest{
 		buildAggTester(ast.AggFuncStddevSamp, mysql.TypeDouble, 5, nil, 1.5811388300841898),
 	}
diff --git a/executor/aggfuncs/func_sum_test.go b/executor/aggfuncs/func_sum_test.go
index b4a744002754b..15e1ebc984524 100644
--- a/executor/aggfuncs/func_sum_test.go
+++ b/executor/aggfuncs/func_sum_test.go
@@ -26,8 +26,6 @@ import (
 )
 
 func TestMergePartialResult4Sum(t *testing.T) {
-	t.Parallel()
-
 	tests := []aggTest{
 		buildAggTester(ast.AggFuncSum, mysql.TypeNewDecimal, 5, types.NewDecFromInt(10), types.NewDecFromInt(9), types.NewDecFromInt(19)),
 		buildAggTester(ast.AggFuncSum, mysql.TypeDouble, 5, 10.0, 9.0, 19.0),
@@ -41,8 +39,6 @@ func TestMergePartialResult4Sum(t *testing.T) {
 }
 
 func TestSum(t *testing.T) {
-	t.Parallel()
-
 	tests := []aggTest{
 		buildAggTester(ast.AggFuncSum, mysql.TypeNewDecimal, 5, nil, types.NewDecFromInt(10)),
 		buildAggTester(ast.AggFuncSum, mysql.TypeDouble, 5, nil, 10.0),
@@ -55,8 +51,6 @@ func TestSum(t *testing.T) {
 }
 
 func TestMemSum(t *testing.T) {
-	t.Parallel()
-
 	tests := []aggMemTest{
 		buildAggMemTester(ast.AggFuncSum, mysql.TypeDouble, 5,
 			aggfuncs.DefPartialResult4SumFloat64Size, defaultUpdateMemDeltaGens, false),
diff --git a/executor/aggfuncs/func_value_test.go b/executor/aggfuncs/func_value_test.go
index cde0a3ecb90ab..b1e322821af9e 100644
--- a/executor/aggfuncs/func_value_test.go
+++ b/executor/aggfuncs/func_value_test.go
@@ -61,8 +61,6 @@ func nthValueEvaluateRowUpdateMemDeltaGens(nth int) updateMemDeltaGens {
 }
 
 func TestMemValue(t *testing.T) {
-	t.Parallel()
-
 	firstMemDeltaGens := nthValueEvaluateRowUpdateMemDeltaGens(1)
 	secondMemDeltaGens := nthValueEvaluateRowUpdateMemDeltaGens(2)
 	fifthMemDeltaGens := nthValueEvaluateRowUpdateMemDeltaGens(5)
diff --git a/executor/aggfuncs/func_varpop_test.go b/executor/aggfuncs/func_varpop_test.go
index a8c59060bf009..40cedacda63eb 100644
--- a/executor/aggfuncs/func_varpop_test.go
+++ b/executor/aggfuncs/func_varpop_test.go
@@ -26,8 +26,6 @@ import (
 )
 
 func TestMergePartialResult4Varpop(t *testing.T) {
-	t.Parallel()
-
 	tests := []aggTest{
 		buildAggTester(ast.AggFuncVarPop, mysql.TypeDouble, 5, types.NewFloat64Datum(float64(2)), types.NewFloat64Datum(float64(2)/float64(3)), types.NewFloat64Datum(float64(59)/float64(8)-float64(19*19)/float64(8*8))),
 	}
@@ -37,8 +35,6 @@ func TestMergePartialResult4Varpop(t *testing.T) {
 }
 
 func TestVarpop(t *testing.T) {
-	t.Parallel()
-
 	tests := []aggTest{
 		buildAggTester(ast.AggFuncVarPop, mysql.TypeDouble, 5, nil, types.NewFloat64Datum(float64(2))),
 	}
@@ -48,8 +44,6 @@ func TestVarpop(t *testing.T) {
 }
 
 func TestMemVarpop(t *testing.T) {
-	t.Parallel()
-
 	tests := []aggMemTest{
 		buildAggMemTester(ast.AggFuncVarPop, mysql.TypeDouble, 5,
 			aggfuncs.DefPartialResult4VarPopFloat64Size, defaultUpdateMemDeltaGens, false),
@@ -59,7 +53,6 @@ func TestMemVarpop(t *testing.T) {
 	for n, test := range tests {
 		test := test
 		t.Run(fmt.Sprintf("%s_%d", test.aggTest.funcName, n), func(t *testing.T) {
-			t.Parallel()
 			testAggMemFunc(t, test)
 		})
 	}
diff --git a/executor/aggfuncs/func_varsamp_test.go b/executor/aggfuncs/func_varsamp_test.go
index fceb8a2a1a559..32396b654f540 100644
--- a/executor/aggfuncs/func_varsamp_test.go
+++ b/executor/aggfuncs/func_varsamp_test.go
@@ -22,8 +22,6 @@ import (
 )
 
 func TestMergePartialResult4Varsamp(t *testing.T) {
-	t.Parallel()
-
 	tests := []aggTest{
 		buildAggTester(ast.AggFuncVarSamp, mysql.TypeDouble, 5, 2.5, 1, 1.9821428571428572),
 	}
@@ -33,8 +31,6 @@ func TestMergePartialResult4Varsamp(t *testing.T) {
 }
 
 func TestVarsamp(t *testing.T) {
-	t.Parallel()
-
 	tests := []aggTest{
 		buildAggTester(ast.AggFuncVarSamp, mysql.TypeDouble, 5, nil, 2.5),
 	}
diff --git a/executor/aggfuncs/row_number_test.go b/executor/aggfuncs/row_number_test.go
index c944fb4f56177..361096daf00de 100644
--- a/executor/aggfuncs/row_number_test.go
+++ b/executor/aggfuncs/row_number_test.go
@@ -23,8 +23,6 @@ import (
 )
 
 func TestMemRowNumber(t *testing.T) {
-	t.Parallel()
-
 	tests := []windowMemTest{
 		buildWindowMemTester(ast.WindowFuncRowNumber, mysql.TypeLonglong, 0, 0, 4,
 			aggfuncs.DefPartialResult4RowNumberSize, defaultUpdateMemDeltaGens),
diff --git a/executor/aggfuncs/window_func_test.go b/executor/aggfuncs/window_func_test.go
index a063951dd44e6..f1854a890c12e 100644
--- a/executor/aggfuncs/window_func_test.go
+++ b/executor/aggfuncs/window_func_test.go
@@ -171,8 +171,6 @@ func buildWindowMemTesterWithArgs(funcName string, tp byte, args []expression.Ex
 }
 
 func TestWindowFunctions(t *testing.T) {
-	t.Parallel()
-
 	tests := []windowTest{
 		buildWindowTester(ast.WindowFuncCumeDist, mysql.TypeLonglong, 0, 1, 1, 1),
 		buildWindowTester(ast.WindowFuncCumeDist, mysql.TypeLonglong, 0, 0, 2, 1, 1),
diff --git a/executor/aggregate_test.go b/executor/aggregate_test.go
index 1064025bd53fa..25b9bd96840e9 100644
--- a/executor/aggregate_test.go
+++ b/executor/aggregate_test.go
@@ -36,7 +36,6 @@ import (
 )
 
 func TestAggregation(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 	tk := testkit.NewTestKit(t, store)
@@ -477,7 +476,6 @@ func TestAggregation(t *testing.T) {
 }
 
 func TestAggPrune(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 	tk := testkit.NewTestKit(t, store)
@@ -505,7 +503,6 @@ func TestAggPrune(t *testing.T) {
 }
 
 func TestGroupConcatAggr(t *testing.T) {
-	t.Parallel()
 	var err error
 	// issue #5411
 	store, clean := testkit.CreateMockStore(t)
@@ -652,7 +649,6 @@ func TestGroupConcatAggr(t *testing.T) {
 }
 
 func TestSelectDistinct(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 	tk := testkit.NewTestKit(t, store)
@@ -667,7 +663,6 @@ func TestSelectDistinct(t *testing.T) {
 }
 
 func TestAggPushDown(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 	tk := testkit.NewTestKit(t, store)
@@ -698,7 +693,6 @@ func TestAggPushDown(t *testing.T) {
 }
 
 func TestOnlyFullGroupBy(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 	tk := testkit.NewTestKit(t, store)
@@ -813,7 +807,6 @@ func TestOnlyFullGroupBy(t *testing.T) {
 }
 
 func TestIssue16279(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 	tk := testkit.NewTestKit(t, store)
@@ -827,7 +820,6 @@ func TestIssue16279(t *testing.T) {
 }
 
 func TestIssue24676(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 	tk := testkit.NewTestKit(t, store)
@@ -845,7 +837,6 @@ func TestIssue24676(t *testing.T) {
 }
 
 func TestAggPushDownPartitionTable(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 	tk := testkit.NewTestKit(t, store)
@@ -880,7 +871,6 @@ func TestAggPushDownPartitionTable(t *testing.T) {
 }
 
 func TestIssue13652(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 	tk := testkit.NewTestKit(t, store)
@@ -897,7 +887,6 @@ func TestIssue13652(t *testing.T) {
 }
 
 func TestIssue14947(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 	tk := testkit.NewTestKit(t, store)
@@ -909,7 +898,6 @@ func TestIssue14947(t *testing.T) {
 }
 
 func TestHaving(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 	tk := testkit.NewTestKit(t, store)
@@ -937,7 +925,6 @@ func TestHaving(t *testing.T) {
 }
 
 func TestIssue26496(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 	tk := testkit.NewTestKit(t, store)
@@ -950,7 +937,6 @@ func TestIssue26496(t *testing.T) {
 }
 
 func TestAggEliminator(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 	tk := testkit.NewTestKit(t, store)
@@ -967,7 +953,6 @@ func TestAggEliminator(t *testing.T) {
 }
 
 func TestClusterIndexMaxMinEliminator(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 	tk := testkit.NewTestKit(t, store)
@@ -984,7 +969,6 @@ func TestClusterIndexMaxMinEliminator(t *testing.T) {
 }
 
 func TestMaxMinFloatScalaFunc(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 	tk := testkit.NewTestKit(t, store)
@@ -998,7 +982,6 @@ func TestMaxMinFloatScalaFunc(t *testing.T) {
 }
 
 func TestBuildProjBelowAgg(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 	tk := testkit.NewTestKit(t, store)
@@ -1014,7 +997,6 @@ func TestBuildProjBelowAgg(t *testing.T) {
 }
 
 func TestInjectProjBelowTopN(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 	tk := testkit.NewTestKit(t, store)
@@ -1036,7 +1018,6 @@ func TestInjectProjBelowTopN(t *testing.T) {
 }
 
 func TestFirstRowEnum(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 	tk := testkit.NewTestKit(t, store)
@@ -1050,7 +1031,6 @@ func TestFirstRowEnum(t *testing.T) {
 }
 
 func TestAggJSON(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 	tk := testkit.NewTestKit(t, store)
@@ -1103,7 +1083,6 @@ func TestAggJSON(t *testing.T) {
 }
 
 func TestIssue10099(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 	tk := testkit.NewTestKit(t, store)
@@ -1116,7 +1095,6 @@ func TestIssue10099(t *testing.T) {
 }
 
 func TestIssue10098(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 	tk := testkit.NewTestKit(t, store)
@@ -1128,7 +1106,6 @@ func TestIssue10098(t *testing.T) {
 }
 
 func TestIssue10608(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 	tk := testkit.NewTestKit(t, store)
@@ -1144,8 +1121,6 @@ func TestIssue10608(t *testing.T) {
 }
 
 func TestIssue12759HashAggCalledByApply(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 	tk := testkit.NewTestKit(t, store)
@@ -1176,7 +1151,6 @@ func TestIssue12759HashAggCalledByApply(t *testing.T) {
 }
 
 func TestPR15242ShallowCopy(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 	tk := testkit.NewTestKit(t, store)
@@ -1194,7 +1168,6 @@ func TestPR15242ShallowCopy(t *testing.T) {
 }
 
 func TestIssue15690(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 	tk := testkit.NewTestKit(t, store)
@@ -1248,7 +1221,6 @@ func TestIssue15690(t *testing.T) {
 }
 
 func TestIssue15958(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 	tk := testkit.NewTestKit(t, store)
@@ -1262,7 +1234,6 @@ func TestIssue15958(t *testing.T) {
 }
 
 func TestIssue17216(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 	tk := testkit.NewTestKit(t, store)
@@ -1277,7 +1248,6 @@ func TestIssue17216(t *testing.T) {
 }
 
 func TestHashAggRuntimeStat(t *testing.T) {
-	t.Parallel()
 	partialInfo := &executor.AggWorkerInfo{
 		Concurrency: 5,
 		WallTime:    int64(time.Second * 20),
@@ -1336,7 +1306,6 @@ func reconstructParallelGroupConcatResult(rows [][]interface{}) []string {
 }
 
 func TestParallelStreamAggGroupConcat(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 	tk := testkit.NewTestKit(t, store)
@@ -1384,7 +1353,6 @@ func TestParallelStreamAggGroupConcat(t *testing.T) {
 }
 
 func TestIssue20658(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 	tk := testkit.NewTestKit(t, store)
@@ -1461,7 +1429,6 @@ func TestIssue20658(t *testing.T) {
 }
 
 func TestIssue23277(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 	tk := testkit.NewTestKit(t, store)
@@ -1495,7 +1462,6 @@ func TestIssue23277(t *testing.T) {
 }
 
 func TestAvgDecimal(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 	tk := testkit.NewTestKit(t, store)
@@ -1518,7 +1484,6 @@ func TestAvgDecimal(t *testing.T) {
 
 // https://github.com/pingcap/tidb/issues/23314
 func TestIssue23314(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 	tk := testkit.NewTestKit(t, store)
diff --git a/executor/analyze_test.go b/executor/analyze_test.go
index b35c1321315e3..29d2aca24ee68 100644
--- a/executor/analyze_test.go
+++ b/executor/analyze_test.go
@@ -53,7 +53,6 @@ import (
 )
 
 func TestAnalyzePartition(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 	tk := testkit.NewTestKit(t, store)
@@ -121,7 +120,6 @@ PARTITION BY RANGE ( a ) (
 }
 
 func TestAnalyzeReplicaReadFollower(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 	tk := testkit.NewTestKit(t, store)
@@ -135,7 +133,6 @@ func TestAnalyzeReplicaReadFollower(t *testing.T) {
 }
 
 func TestClusterIndexAnalyze(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 	tk := testkit.NewTestKit(t, store)
@@ -168,7 +165,6 @@ func TestClusterIndexAnalyze(t *testing.T) {
 }
 
 func TestAnalyzeRestrict(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 	tk := testkit.NewTestKit(t, store)
@@ -182,7 +178,6 @@ func TestAnalyzeRestrict(t *testing.T) {
 }
 
 func TestAnalyzeParameters(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 	dom, err := session.BootstrapSession(store)
@@ -244,7 +239,6 @@ func TestAnalyzeParameters(t *testing.T) {
 }
 
 func TestAnalyzeTooLongColumns(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 	dom, err := session.BootstrapSession(store)
@@ -268,7 +262,6 @@ func TestAnalyzeTooLongColumns(t *testing.T) {
 }
 
 func TestAnalyzeIndexExtractTopN(t *testing.T) {
-	t.Parallel()
 	_ = checkHistogram
 	t.Skip("unstable, skip it and fix it before 20210618")
 	store, err := mockstore.NewMockStore()
@@ -318,7 +311,6 @@ func TestAnalyzeIndexExtractTopN(t *testing.T) {
 }
 
 func TestAnalyzeFastSample(t *testing.T) {
-	t.Parallel()
 	var cls testutils.Cluster
 	store, err := mockstore.NewMockStore(
 		mockstore.WithClusterInspector(func(c testutils.Cluster) {
@@ -426,7 +418,6 @@ func checkHistogram(sc *stmtctx.StatementContext, hg *statistics.Histogram) (boo
 }
 
 func TestFastAnalyze(t *testing.T) {
-	t.Parallel()
 	t.Skip("Skip this unstable test(#25782) and bring it back before 2021-07-29.")
 	var cls testutils.Cluster
 	store, err := mockstore.NewMockStore(
@@ -547,7 +538,6 @@ func TestFastAnalyze(t *testing.T) {
 }
 
 func TestIssue15993(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 	tk := testkit.NewTestKit(t, store)
@@ -561,7 +551,6 @@ func TestIssue15993(t *testing.T) {
 }
 
 func TestIssue15751(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 	tk := testkit.NewTestKit(t, store)
@@ -576,7 +565,6 @@ func TestIssue15751(t *testing.T) {
 }
 
 func TestIssue15752(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 	tk := testkit.NewTestKit(t, store)
@@ -615,7 +603,6 @@ func (c *regionProperityClient) SendRequest(ctx context.Context, addr string, re
 }
 
 func TestFastAnalyzeRetryRowCount(t *testing.T) {
-	t.Parallel()
 	cli := &regionProperityClient{}
 	hijackClient := func(c tikv.Client) tikv.Client {
 		cli.Client = c
@@ -663,7 +650,6 @@ func TestFastAnalyzeRetryRowCount(t *testing.T) {
 }
 
 func TestFailedAnalyzeRequest(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 	tk := testkit.NewTestKit(t, store)
@@ -679,7 +665,6 @@ func TestFailedAnalyzeRequest(t *testing.T) {
 }
 
 func TestExtractTopN(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 	dom, err := session.BootstrapSession(store)
@@ -735,7 +720,6 @@ func TestExtractTopN(t *testing.T) {
 }
 
 func TestHashInTopN(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 	dom, err := session.BootstrapSession(store)
@@ -778,7 +762,6 @@ func TestHashInTopN(t *testing.T) {
 }
 
 func TestNormalAnalyzeOnCommonHandle(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 	tk := testkit.NewTestKit(t, store)
@@ -831,7 +814,6 @@ func TestNormalAnalyzeOnCommonHandle(t *testing.T) {
 }
 
 func TestDefaultValForAnalyze(t *testing.T) {
-	t.Parallel()
 	t.Skip("skip race test")
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
@@ -870,7 +852,6 @@ func TestDefaultValForAnalyze(t *testing.T) {
 }
 
 func TestAnalyzeFullSamplingOnIndexWithVirtualColumnOrPrefixColumn(t *testing.T) {
-	t.Parallel()
 	t.Skip("unstable, skip it and fix it before 20210624")
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
@@ -904,7 +885,6 @@ func TestAnalyzeFullSamplingOnIndexWithVirtualColumnOrPrefixColumn(t *testing.T)
 }
 
 func TestSnapshotAnalyze(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 	tk := testkit.NewTestKit(t, store)
@@ -954,7 +934,6 @@ func TestSnapshotAnalyze(t *testing.T) {
 }
 
 func TestAdjustSampleRateNote(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 	tk := testkit.NewTestKit(t, store)
diff --git a/executor/batch_point_get_test.go b/executor/batch_point_get_test.go
index b4a167e910cb0..27c035e52a433 100644
--- a/executor/batch_point_get_test.go
+++ b/executor/batch_point_get_test.go
@@ -30,8 +30,6 @@ import (
 )
 
 func TestBatchPointGetExec(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -80,8 +78,6 @@ func TestBatchPointGetExec(t *testing.T) {
 }
 
 func TestBatchPointGetInTxn(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -112,8 +108,6 @@ func TestBatchPointGetInTxn(t *testing.T) {
 }
 
 func TestBatchPointGetCache(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -128,8 +122,6 @@ func TestBatchPointGetCache(t *testing.T) {
 }
 
 func TestIssue18843(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -145,8 +137,6 @@ func TestIssue18843(t *testing.T) {
 }
 
 func TestIssue24562(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -160,8 +150,6 @@ func TestIssue24562(t *testing.T) {
 }
 
 func TestBatchPointGetUnsignedHandleWithSort(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -177,8 +165,6 @@ func TestBatchPointGetUnsignedHandleWithSort(t *testing.T) {
 }
 
 func TestBatchPointGetLockExistKey(t *testing.T) {
-	t.Parallel()
-
 	var wg sync.WaitGroup
 	errCh := make(chan error)
 	store, clean := testkit.CreateMockStore(t)
@@ -324,8 +310,6 @@ func TestBatchPointGetLockExistKey(t *testing.T) {
 }
 
 func TestBatchPointGetIssue25167(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
diff --git a/executor/brie_test.go b/executor/brie_test.go
index 0833a4ca85f39..b4eca0564da45 100644
--- a/executor/brie_test.go
+++ b/executor/brie_test.go
@@ -35,7 +35,6 @@ import (
 )
 
 func TestGlueGetVersion(t *testing.T) {
-	t.Parallel()
 	g := tidbGlueSession{}
 	version := g.GetVersion()
 	require.Contains(t, version, `Release Version`)
@@ -67,7 +66,6 @@ func fetchShowBRIEResult(t *testing.T, e *ShowExec, brieColTypes []*types.FieldT
 }
 
 func TestFetchShowBRIE(t *testing.T) {
-	t.Parallel()
 	// Compose a mocked session manager.
 	ps := make([]*util.ProcessInfo, 0, 1)
 	pi := &util.ProcessInfo{
diff --git a/executor/concurrent_map_test.go b/executor/concurrent_map_test.go
index aa6a318874590..6a149c8dc93db 100644
--- a/executor/concurrent_map_test.go
+++ b/executor/concurrent_map_test.go
@@ -24,7 +24,6 @@ import (
 
 // TestConcurrentMap first inserts 1000 entries, then checks them
 func TestConcurrentMap(t *testing.T) {
-	t.Parallel()
 	m := newConcurrentMap()
 	const iterations = 1000
 	const mod = 111
diff --git a/executor/cte_test.go b/executor/cte_test.go
index 3a9c3a5a7987f..bf4ec37b99095 100644
--- a/executor/cte_test.go
+++ b/executor/cte_test.go
@@ -23,8 +23,6 @@ import (
 )
 
 func TestBasicCTE(t *testing.T) {
-	t.Parallel()
-
 	store, close := testkit.CreateMockStore(t)
 	defer close()
 
@@ -74,8 +72,6 @@ func TestBasicCTE(t *testing.T) {
 }
 
 func TestUnionDistinct(t *testing.T) {
-	t.Parallel()
-
 	store, close := testkit.CreateMockStore(t)
 	defer close()
 
@@ -103,8 +99,6 @@ func TestUnionDistinct(t *testing.T) {
 }
 
 func TestCTEMaxRecursionDepth(t *testing.T) {
-	t.Parallel()
-
 	store, close := testkit.CreateMockStore(t)
 	defer close()
 
@@ -146,8 +140,6 @@ func TestCTEMaxRecursionDepth(t *testing.T) {
 }
 
 func TestCTEWithLimit(t *testing.T) {
-	t.Parallel()
-
 	store, close := testkit.CreateMockStore(t)
 	defer close()
 
diff --git a/executor/delete_test.go b/executor/delete_test.go
index bfcd06c7efb63..64c61996fac66 100644
--- a/executor/delete_test.go
+++ b/executor/delete_test.go
@@ -24,8 +24,6 @@ import (
 )
 
 func TestDeleteLockKey(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -111,8 +109,6 @@ func TestDeleteLockKey(t *testing.T) {
 }
 
 func TestIssue21200(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
diff --git a/executor/executor_pkg_test.go b/executor/executor_pkg_test.go
index dc3e68acaa4f5..5cd983fccd5f0 100644
--- a/executor/executor_pkg_test.go
+++ b/executor/executor_pkg_test.go
@@ -103,7 +103,6 @@ func TestExecutorPkg(t *testing.T) {
 }
 
 func SubTestShowProcessList(t *testing.T) {
-	t.Parallel()
 	// Compose schema.
 	names := []string{"Id", "User", "Host", "db", "Command", "Time", "State", "Info"}
 	ftypes := []byte{mysql.TypeLonglong, mysql.TypeVarchar, mysql.TypeVarchar,
@@ -177,7 +176,6 @@ func buildSchema(names []string, ftypes []byte) *expression.Schema {
 }
 
 func SubTestBuildKvRangesForIndexJoinWithoutCwc(t *testing.T) {
-	t.Parallel()
 	indexRanges := make([]*ranger.Range, 0, 6)
 	indexRanges = append(indexRanges, generateIndexRange(1, 1, 1, 1, 1))
 	indexRanges = append(indexRanges, generateIndexRange(1, 1, 2, 1, 1))
@@ -222,7 +220,6 @@ func generateDatumSlice(vals ...int64) []types.Datum {
 }
 
 func SubTestGetFieldsFromLine(t *testing.T) {
-	t.Parallel()
 	tests := []struct {
 		input    string
 		expected []string
@@ -281,7 +278,6 @@ func assertEqualStrings(t *testing.T, got []field, expect []string) {
 }
 
 func SubTestSlowQueryRuntimeStats(t *testing.T) {
-	t.Parallel()
 	stats := &slowQueryRuntimeStats{
 		totalFileNum: 2,
 		readFileNum:  2,
@@ -392,7 +388,6 @@ func getGrowing(m aggPartialResultMapper) bool {
 }
 
 func SubTestFilterTemporaryTableKeys(t *testing.T) {
-	t.Parallel()
 	vars := variable.NewSessionVars()
 	const tableID int64 = 3
 	vars.TxnCtx = &variable.TransactionContext{
diff --git a/executor/grant_test.go b/executor/grant_test.go
index a42b546e42b05..240e9e5e41154 100644
--- a/executor/grant_test.go
+++ b/executor/grant_test.go
@@ -29,8 +29,6 @@ import (
 )
 
 func TestGrantGlobal(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -71,8 +69,6 @@ func TestGrantGlobal(t *testing.T) {
 }
 
 func TestGrantDBScope(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -112,8 +108,6 @@ func TestGrantDBScope(t *testing.T) {
 }
 
 func TestWithGrantOption(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -138,8 +132,6 @@ func TestWithGrantOption(t *testing.T) {
 }
 
 func TestGrantTableScope(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -184,8 +176,6 @@ func TestGrantTableScope(t *testing.T) {
 }
 
 func TestGrantColumnScope(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -232,8 +222,6 @@ func TestGrantColumnScope(t *testing.T) {
 }
 
 func TestIssue2456(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -246,8 +234,6 @@ func TestIssue2456(t *testing.T) {
 }
 
 func TestNoAutoCreateUser(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -260,8 +246,6 @@ func TestNoAutoCreateUser(t *testing.T) {
 }
 
 func TestCreateUserWhenGrant(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -278,8 +262,6 @@ func TestCreateUserWhenGrant(t *testing.T) {
 }
 
 func TestGrantPrivilegeAtomic(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -334,8 +316,6 @@ func TestGrantPrivilegeAtomic(t *testing.T) {
 }
 
 func TestIssue2654(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -348,8 +328,6 @@ func TestIssue2654(t *testing.T) {
 }
 
 func TestGrantUnderANSIQuotes(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -364,8 +342,6 @@ func TestGrantUnderANSIQuotes(t *testing.T) {
 }
 
 func TestMaintainRequire(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -439,8 +415,6 @@ func TestMaintainRequire(t *testing.T) {
 }
 
 func TestMaintainAuthString(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -452,8 +426,6 @@ func TestMaintainAuthString(t *testing.T) {
 }
 
 func TestGrantOnNonExistTable(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -515,8 +487,6 @@ func TestGrantOnNonExistTable(t *testing.T) {
 }
 
 func TestIssue22721(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -531,8 +501,6 @@ func TestIssue22721(t *testing.T) {
 }
 
 func TestPerformanceSchemaPrivGrant(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -581,8 +549,6 @@ func TestPerformanceSchemaPrivGrant(t *testing.T) {
 }
 
 func TestGrantDynamicPrivs(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -617,8 +583,6 @@ func TestGrantDynamicPrivs(t *testing.T) {
 }
 
 func TestNonExistTableIllegalGrant(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
diff --git a/executor/index_advise_test.go b/executor/index_advise_test.go
index 79d1f0e107a05..5371ecd051bc1 100644
--- a/executor/index_advise_test.go
+++ b/executor/index_advise_test.go
@@ -25,7 +25,6 @@ import (
 )
 
 func TestIndexAdvise(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
diff --git a/executor/index_lookup_join_test.go b/executor/index_lookup_join_test.go
index 3c975e77cbb77..262190dd1ac81 100644
--- a/executor/index_lookup_join_test.go
+++ b/executor/index_lookup_join_test.go
@@ -27,7 +27,6 @@ import (
 )
 
 func TestIndexLookupJoinHang(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -72,7 +71,6 @@ func TestIndexLookupJoinHang(t *testing.T) {
 }
 
 func TestIndexJoinUnionScan(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -127,7 +125,6 @@ func TestIndexJoinUnionScan(t *testing.T) {
 }
 
 func TestBatchIndexJoinUnionScanTest(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -150,7 +147,6 @@ func TestBatchIndexJoinUnionScanTest(t *testing.T) {
 }
 
 func TestInapplicableIndexJoinHint(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -194,7 +190,6 @@ func TestInapplicableIndexJoinHint(t *testing.T) {
 }
 
 func TestIndexJoinOverflow(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -210,7 +205,6 @@ func TestIndexJoinOverflow(t *testing.T) {
 }
 
 func TestIssue11061(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -225,7 +219,6 @@ func TestIssue11061(t *testing.T) {
 }
 
 func TestIndexJoinPartitionTable(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -240,7 +233,6 @@ func TestIndexJoinPartitionTable(t *testing.T) {
 }
 
 func TestIndexJoinMultiCondition(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -255,7 +247,6 @@ func TestIndexJoinMultiCondition(t *testing.T) {
 }
 
 func TestIssue16887(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -273,7 +264,6 @@ func TestIssue16887(t *testing.T) {
 }
 
 func TestIndexJoinEnumSetIssue19233(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -316,7 +306,6 @@ func TestIndexJoinEnumSetIssue19233(t *testing.T) {
 }
 
 func TestIssue19411(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -336,7 +325,6 @@ func TestIssue19411(t *testing.T) {
 }
 
 func TestIssue23653(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -352,7 +340,6 @@ func TestIssue23653(t *testing.T) {
 }
 
 func TestIssue23656(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -369,7 +356,6 @@ func TestIssue23656(t *testing.T) {
 }
 
 func TestIssue23722(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -406,7 +392,6 @@ func TestIssue23722(t *testing.T) {
 }
 
 func TestIssue24547(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -422,7 +407,6 @@ func TestIssue24547(t *testing.T) {
 }
 
 func TestIssue27138(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -471,7 +455,6 @@ PARTITIONS 1`)
 }
 
 func TestIssue27893(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -491,7 +474,6 @@ func TestPartitionTableIndexJoinAndIndexReader(t *testing.T) {
 	if israce.RaceEnabled {
 		t.Skip("exhaustive types test, skip race test")
 	}
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
diff --git a/executor/prepared_test.go b/executor/prepared_test.go
index 7117e6500ee66..5908af0437848 100644
--- a/executor/prepared_test.go
+++ b/executor/prepared_test.go
@@ -30,7 +30,6 @@ import (
 )
 
 func TestPreparedNameResolver(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 	tk := testkit.NewTestKit(t, store)
@@ -47,7 +46,6 @@ func TestPreparedNameResolver(t *testing.T) {
 
 // a 'create table' DDL statement should be accepted if it has no parameters.
 func TestPreparedDDL(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 	tk := testkit.NewTestKit(t, store)
@@ -58,7 +56,6 @@ func TestPreparedDDL(t *testing.T) {
 
 // TestUnsupportedStmtForPrepare is related to https://github.com/pingcap/tidb/issues/17412
 func TestUnsupportedStmtForPrepare(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 	tk := testkit.NewTestKit(t, store)
@@ -70,7 +67,6 @@ func TestUnsupportedStmtForPrepare(t *testing.T) {
 }
 
 func TestIgnorePlanCache(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 	tk := testkit.NewTestKit(t, store)
@@ -123,7 +119,6 @@ func (sm *mockSessionManager2) ServerID() uint64 {
 }
 
 func TestPreparedStmtWithHint(t *testing.T) {
-	t.Parallel()
 	// see https://github.com/pingcap/tidb/issues/18535
 	store, dom, err := newStoreWithBootstrap()
 	require.NoError(t, err)
diff --git a/executor/set_test.go b/executor/set_test.go
index 77ab1b1d26c1a..9be1f1794ce1c 100644
--- a/executor/set_test.go
+++ b/executor/set_test.go
@@ -587,6 +587,12 @@ func (s *testSerialSuite1) TestSetVar(c *C) {
 	tk.MustExec("set global tidb_enable_tso_follower_proxy = 0")
 	tk.MustQuery("select @@tidb_enable_tso_follower_proxy").Check(testkit.Rows("0"))
 	c.Assert(tk.ExecToErr("set tidb_enable_tso_follower_proxy = 1"), NotNil)
+
+	tk.MustQuery("select @@tidb_enable_historical_stats").Check(testkit.Rows("0"))
+	tk.MustExec("set global tidb_enable_historical_stats = 1")
+	tk.MustQuery("select @@tidb_enable_historical_stats").Check(testkit.Rows("1"))
+	tk.MustExec("set global tidb_enable_historical_stats = 0")
+	tk.MustQuery("select @@tidb_enable_historical_stats").Check(testkit.Rows("0"))
 }
 
 func (s *testSuite5) TestTruncateIncorrectIntSessionVar(c *C) {
diff --git a/executor/show_stats_test.go b/executor/show_stats_test.go
index d8e38c1e9c1c4..1f2ffafd8c54d 100644
--- a/executor/show_stats_test.go
+++ b/executor/show_stats_test.go
@@ -27,7 +27,6 @@ import (
 )
 
 func TestShowStatsMeta(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -47,7 +46,6 @@ func TestShowStatsMeta(t *testing.T) {
 }
 
 func TestShowStatsHistograms(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -79,7 +77,6 @@ func TestShowStatsHistograms(t *testing.T) {
 }
 
 func TestShowStatsBuckets(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -126,7 +123,6 @@ func TestShowStatsBuckets(t *testing.T) {
 }
 
 func TestShowStatsHasNullValue(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -192,7 +188,6 @@ func TestShowStatsHasNullValue(t *testing.T) {
 }
 
 func TestShowPartitionStats(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -233,7 +228,6 @@ func TestShowPartitionStats(t *testing.T) {
 }
 
 func TestShowStatusSnapshot(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -262,7 +256,6 @@ func TestShowStatusSnapshot(t *testing.T) {
 }
 
 func TestShowStatsExtended(t *testing.T) {
-	t.Parallel()
 	store, dom, clean := testkit.CreateMockStoreAndDomain(t)
 	defer clean()
 
@@ -317,7 +310,6 @@ func TestShowStatsExtended(t *testing.T) {
 }
 
 func TestShowColumnStatsUsage(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -352,7 +344,6 @@ func TestShowColumnStatsUsage(t *testing.T) {
 }
 
 func TestShowHistogramsInFlight(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
diff --git a/executor/shuffle_test.go b/executor/shuffle_test.go
index bc1b7a82d2bb8..92f96cf74654c 100644
--- a/executor/shuffle_test.go
+++ b/executor/shuffle_test.go
@@ -26,8 +26,6 @@ import (
 )
 
 func TestPartitionRangeSplitter(t *testing.T) {
-	t.Parallel()
-
 	ctx := mock.NewContext()
 	concurrency := 2
 
diff --git a/executor/slow_query_test.go b/executor/slow_query_test.go
index 6d2e4e4870320..4fdd9281c5142 100644
--- a/executor/slow_query_test.go
+++ b/executor/slow_query_test.go
@@ -486,8 +486,6 @@ select 7;`
 }
 
 func TestSplitbyColon(t *testing.T) {
-	t.Parallel()
-
 	cases := []struct {
 		line   string
 		fields []string
diff --git a/executor/union_scan_test.go b/executor/union_scan_test.go
index 1fe3f4dbbacbc..6133010ec29da 100644
--- a/executor/union_scan_test.go
+++ b/executor/union_scan_test.go
@@ -23,7 +23,6 @@ import (
 )
 
 func TestDirtyTransaction(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 	tk := testkit.NewTestKit(t, store)
@@ -154,7 +153,6 @@ func TestDirtyTransaction(t *testing.T) {
 }
 
 func TestUnionScanWithCastCondition(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 	tk := testkit.NewTestKit(t, store)
@@ -170,7 +168,6 @@ func TestUnionScanWithCastCondition(t *testing.T) {
 }
 
 func TestUnionScanForMemBufferReader(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 	tk := testkit.NewTestKit(t, store)
@@ -309,7 +306,6 @@ func TestUnionScanForMemBufferReader(t *testing.T) {
 }
 
 func TestForUpdateUntouchedIndex(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 	tk := testkit.NewTestKit(t, store)
@@ -350,7 +346,6 @@ func TestForUpdateUntouchedIndex(t *testing.T) {
 }
 
 func TestUpdateScanningHandles(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 	tk := testkit.NewTestKit(t, store)
@@ -385,7 +380,6 @@ func TestUpdateScanningHandles(t *testing.T) {
 
 // See https://github.com/pingcap/tidb/issues/19136
 func TestForApplyAndUnionScan(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 	tk := testkit.NewTestKit(t, store)
diff --git a/executor/utils_test.go b/executor/utils_test.go
index 53301fb255a00..3c8a32de25cc5 100644
--- a/executor/utils_test.go
+++ b/executor/utils_test.go
@@ -22,8 +22,6 @@ import (
 )
 
 func TestBatchRetrieverHelper(t *testing.T) {
-	t.Parallel()
-
 	rangeStarts := make([]int, 0)
 	rangeEnds := make([]int, 0)
 	collect := func(start, end int) error {
diff --git a/executor/write_concurrent_test.go b/executor/write_concurrent_test.go
index 58e7f37ef4777..141cec3da472d 100644
--- a/executor/write_concurrent_test.go
+++ b/executor/write_concurrent_test.go
@@ -24,8 +24,6 @@ import (
 )
 
 func TestBatchInsertWithOnDuplicate(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
diff --git a/executor/write_test.go b/executor/write_test.go
index f68e94ccc98e7..04609968d486a 100644
--- a/executor/write_test.go
+++ b/executor/write_test.go
@@ -42,7 +42,6 @@ import (
 )
 
 func TestInsert(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 	tk := testkit.NewTestKit(t, store)
@@ -326,7 +325,6 @@ func TestInsert(t *testing.T) {
 }
 
 func TestMultiBatch(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 	tk := testkit.NewTestKit(t, store)
@@ -341,7 +339,6 @@ func TestMultiBatch(t *testing.T) {
 }
 
 func TestInsertAutoInc(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 	tk := testkit.NewTestKit(t, store)
@@ -477,7 +474,6 @@ func TestInsertAutoInc(t *testing.T) {
 }
 
 func TestInsertIgnore(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 	var cfg kv.InjectionConfig
@@ -598,7 +594,6 @@ commit;`
 }
 
 func TestInsertOnDup(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 	var cfg kv.InjectionConfig
@@ -766,7 +761,6 @@ commit;`
 }
 
 func TestInsertIgnoreOnDup(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 	tk := testkit.NewTestKit(t, store)
@@ -821,7 +815,6 @@ func TestInsertIgnoreOnDup(t *testing.T) {
 }
 
 func TestInsertSetWithDefault(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 	tk := testkit.NewTestKit(t, store)
@@ -871,7 +864,6 @@ func TestInsertSetWithDefault(t *testing.T) {
 }
 
 func TestInsertOnDupUpdateDefault(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 	tk := testkit.NewTestKit(t, store)
@@ -919,7 +911,6 @@ func TestInsertOnDupUpdateDefault(t *testing.T) {
 }
 
 func TestReplace(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 	tk := testkit.NewTestKit(t, store)
@@ -1103,7 +1094,6 @@ func TestReplace(t *testing.T) {
 }
 
 func TestGeneratedColumnForInsert(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 	tk := testkit.NewTestKit(t, store)
@@ -1155,7 +1145,6 @@ func TestGeneratedColumnForInsert(t *testing.T) {
 }
 
 func TestPartitionedTableReplace(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 	tk := testkit.NewTestKit(t, store)
@@ -1297,7 +1286,6 @@ func TestPartitionedTableReplace(t *testing.T) {
 }
 
 func TestHashPartitionedTableReplace(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 	tk := testkit.NewTestKit(t, store)
@@ -1417,7 +1405,6 @@ func TestHashPartitionedTableReplace(t *testing.T) {
 }
 
 func TestPartitionedTableUpdate(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 	tk := testkit.NewTestKit(t, store)
@@ -1527,7 +1514,6 @@ func TestPartitionedTableUpdate(t *testing.T) {
 
 // TestUpdateCastOnlyModifiedValues for issue #4514.
 func TestUpdateCastOnlyModifiedValues(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 	tk := testkit.NewTestKit(t, store)
@@ -1576,7 +1562,6 @@ func fillMultiTableForUpdate(tk *testkit.TestKit) {
 }
 
 func TestMultipleTableUpdate(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 	tk := testkit.NewTestKit(t, store)
@@ -1644,7 +1629,6 @@ func TestMultipleTableUpdate(t *testing.T) {
 }
 
 func TestDelete(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 	tk := testkit.NewTestKit(t, store)
@@ -1702,7 +1686,6 @@ func TestPartitionedTableDelete(t *testing.T) {
 			  PARTITION p2 VALUES LESS THAN (16),
 			  PARTITION p3 VALUES LESS THAN (21))`
 
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 	tk := testkit.NewTestKit(t, store)
@@ -1768,7 +1751,6 @@ func fillDataMultiTable(tk *testkit.TestKit) {
 }
 
 func TestMultiTableDelete(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 	tk := testkit.NewTestKit(t, store)
@@ -1783,7 +1765,6 @@ func TestMultiTableDelete(t *testing.T) {
 }
 
 func TestQualifiedDelete(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 	tk := testkit.NewTestKit(t, store)
@@ -1822,7 +1803,6 @@ func TestQualifiedDelete(t *testing.T) {
 }
 
 func TestLoadDataMissingColumn(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 	tk := testkit.NewTestKit(t, store)
@@ -1864,7 +1844,6 @@ func TestLoadDataMissingColumn(t *testing.T) {
 }
 
 func TestIssue18681(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 	tk := testkit.NewTestKit(t, store)
@@ -1900,7 +1879,6 @@ func TestIssue18681(t *testing.T) {
 
 func TestLoadData(t *testing.T) {
 	trivialMsg := "Records: 1  Deleted: 0  Skipped: 0  Warnings: 0"
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 	tk := testkit.NewTestKit(t, store)
@@ -2100,7 +2078,6 @@ func TestLoadData(t *testing.T) {
 
 func TestLoadDataEscape(t *testing.T) {
 	trivialMsg := "Records: 1  Deleted: 0  Skipped: 0  Warnings: 0"
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 	tk := testkit.NewTestKit(t, store)
@@ -2154,7 +2131,6 @@ func TestLoadDataWithLongContent(t *testing.T) {
 // TestLoadDataSpecifiedColumns reuse TestLoadDataEscape's test case :-)
 func TestLoadDataSpecifiedColumns(t *testing.T) {
 	trivialMsg := "Records: 1  Deleted: 0  Skipped: 0  Warnings: 0"
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 	tk := testkit.NewTestKit(t, store)
@@ -2183,7 +2159,6 @@ func TestLoadDataSpecifiedColumns(t *testing.T) {
 }
 
 func TestLoadDataIgnoreLines(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 	tk := testkit.NewTestKit(t, store)
@@ -2206,7 +2181,6 @@ func TestLoadDataIgnoreLines(t *testing.T) {
 
 // TestLoadDataOverflowBigintUnsigned related to issue 6360
 func TestLoadDataOverflowBigintUnsigned(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 	tk := testkit.NewTestKit(t, store)
@@ -2228,7 +2202,6 @@ func TestLoadDataOverflowBigintUnsigned(t *testing.T) {
 }
 
 func TestLoadDataIntoPartitionedTable(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 	tk := testkit.NewTestKit(t, store)
@@ -2256,7 +2229,6 @@ func TestLoadDataIntoPartitionedTable(t *testing.T) {
 }
 
 func TestNullDefault(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 	tk := testkit.NewTestKit(t, store)
@@ -2271,7 +2243,6 @@ func TestNullDefault(t *testing.T) {
 }
 
 func TestNotNullDefault(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 	tk := testkit.NewTestKit(t, store)
@@ -2343,7 +2314,6 @@ func TestLatch(t *testing.T) {
 
 // TestIssue4067 Test issue https://github.com/pingcap/tidb/issues/4067
 func TestIssue4067(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 	tk := testkit.NewTestKit(t, store)
@@ -2360,7 +2330,6 @@ func TestIssue4067(t *testing.T) {
 }
 
 func TestInsertCalculatedValue(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 	tk := testkit.NewTestKit(t, store)
@@ -2484,7 +2453,6 @@ func TestInsertCalculatedValue(t *testing.T) {
 }
 
 func TestDataTooLongErrMsg(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 	tk := testkit.NewTestKit(t, store)
@@ -2500,7 +2468,6 @@ func TestDataTooLongErrMsg(t *testing.T) {
 }
 
 func TestUpdateSelect(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 	tk := testkit.NewTestKit(t, store)
@@ -2515,7 +2482,6 @@ func TestUpdateSelect(t *testing.T) {
 }
 
 func TestUpdateDelete(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 	tk := testkit.NewTestKit(t, store)
@@ -2538,7 +2504,6 @@ func TestUpdateDelete(t *testing.T) {
 }
 
 func TestUpdateAffectRowCnt(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 	tk := testkit.NewTestKit(t, store)
@@ -2560,7 +2525,6 @@ func TestUpdateAffectRowCnt(t *testing.T) {
 }
 
 func TestReplaceLog(t *testing.T) {
-	t.Parallel()
 	store, domain, clean := testkit.CreateMockStoreAndDomain(t)
 	defer clean()
 	tk := testkit.NewTestKit(t, store)
@@ -2596,7 +2560,6 @@ func TestReplaceLog(t *testing.T) {
 // There is no need to do the rebase when updating a record if the auto-increment ID not changed.
 // This could make the auto ID increasing speed slower.
 func TestRebaseIfNeeded(t *testing.T) {
-	t.Parallel()
 	store, domain, clean := testkit.CreateMockStoreAndDomain(t)
 	defer clean()
 	tk := testkit.NewTestKit(t, store)
@@ -2631,7 +2594,6 @@ func TestRebaseIfNeeded(t *testing.T) {
 }
 
 func TestDeferConstraintCheckForDelete(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 	tk := testkit.NewTestKit(t, store)
@@ -2684,7 +2646,6 @@ func TestDeferConstraintCheckForDelete(t *testing.T) {
 }
 
 func TestDeferConstraintCheckForInsert(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 	tk := testkit.NewTestKit(t, store)
@@ -2811,7 +2772,6 @@ func TestDeferConstraintCheckForInsert(t *testing.T) {
 }
 
 func TestPessimisticDeleteYourWrites(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -2841,7 +2801,6 @@ func TestPessimisticDeleteYourWrites(t *testing.T) {
 }
 
 func TestDefEnumInsert(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 	tk := testkit.NewTestKit(t, store)
@@ -2852,7 +2811,6 @@ func TestDefEnumInsert(t *testing.T) {
 }
 
 func TestIssue11059(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 	tk := testkit.NewTestKit(t, store)
@@ -2865,7 +2823,6 @@ func TestIssue11059(t *testing.T) {
 }
 
 func TestSetWithRefGenCol(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 	tk := testkit.NewTestKit(t, store)
@@ -2911,7 +2868,6 @@ func TestSetWithRefGenCol(t *testing.T) {
 }
 
 func TestSetWithCurrentTimestampAndNow(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 	tk := testkit.NewTestKit(t, store)
@@ -2926,7 +2882,6 @@ func TestSetWithCurrentTimestampAndNow(t *testing.T) {
 }
 
 func TestApplyWithPointAndBatchPointGet(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 	tk := testkit.NewTestKit(t, store)
@@ -2970,7 +2925,6 @@ from t order by c_str;`).Check(testkit.Rows("10"))
 }
 
 func TestWriteListPartitionTable(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 	tk := testkit.NewTestKit(t, store)
@@ -3021,7 +2975,6 @@ func TestWriteListPartitionTable(t *testing.T) {
 }
 
 func TestWriteListColumnsPartitionTable(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 	tk := testkit.NewTestKit(t, store)
@@ -3073,7 +3026,6 @@ func TestWriteListColumnsPartitionTable(t *testing.T) {
 
 // TestWriteListPartitionTable1 test for write list partition when the partition expression is simple.
 func TestWriteListPartitionTable1(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 	tk := testkit.NewTestKit(t, store)
@@ -3201,7 +3153,6 @@ func TestWriteListPartitionTable1(t *testing.T) {
 
 // TestWriteListPartitionTable2 test for write list partition when the partition expression is complicated and contain generated column.
 func TestWriteListPartitionTable2(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 	tk := testkit.NewTestKit(t, store)
@@ -3329,7 +3280,6 @@ func TestWriteListPartitionTable2(t *testing.T) {
 }
 
 func TestWriteListColumnsPartitionTable1(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 	tk := testkit.NewTestKit(t, store)
@@ -3458,7 +3408,6 @@ func TestWriteListColumnsPartitionTable1(t *testing.T) {
 
 // TestWriteListColumnsPartitionTable2 test for write list partition when the partition by multi-columns.
 func TestWriteListColumnsPartitionTable2(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 	tk := testkit.NewTestKit(t, store)
@@ -3610,7 +3559,6 @@ func TestWriteListColumnsPartitionTable2(t *testing.T) {
 
 // TestWriteListColumnsPartitionTable2 test for write list partition when the partition by multi-columns.
 func TestWriteListPartitionTableIssue21437(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 	tk := testkit.NewTestKit(t, store)
@@ -3623,7 +3571,6 @@ func TestWriteListPartitionTableIssue21437(t *testing.T) {
 }
 
 func TestListPartitionWithAutoRandom(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 	tk := testkit.NewTestKit(t, store)
@@ -3649,7 +3596,6 @@ func TestListPartitionWithAutoRandom(t *testing.T) {
 }
 
 func TestListPartitionWithAutoIncrement(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 	tk := testkit.NewTestKit(t, store)
@@ -3675,7 +3621,6 @@ func TestListPartitionWithAutoIncrement(t *testing.T) {
 }
 
 func TestListPartitionWithGeneratedColumn(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 	tk := testkit.NewTestKit(t, store)
@@ -3723,7 +3668,6 @@ func TestListPartitionWithGeneratedColumn(t *testing.T) {
 }
 
 func TestListPartitionWithGeneratedColumn1(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 	tk := testkit.NewTestKit(t, store)
@@ -3793,7 +3737,6 @@ func TestListPartitionWithGeneratedColumn1(t *testing.T) {
 }
 
 func TestListPartitionWithGeneratedColumn2(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 	tk := testkit.NewTestKit(t, store)
@@ -3838,7 +3781,6 @@ func TestListPartitionWithGeneratedColumn2(t *testing.T) {
 }
 
 func TestListColumnsPartitionWithGeneratedColumn(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 	tk := testkit.NewTestKit(t, store)
@@ -3865,7 +3807,6 @@ func TestListColumnsPartitionWithGeneratedColumn(t *testing.T) {
 }
 
 func TestIssue22496(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 	tk := testkit.NewTestKit(t, store)
@@ -3909,7 +3850,6 @@ func TestEqualDatumsAsBinary(t *testing.T) {
 }
 
 func TestIssue21232(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 	tk := testkit.NewTestKit(t, store)
diff --git a/expression/aggregation/agg_to_pb_test.go b/expression/aggregation/agg_to_pb_test.go
index 3ab6b90e460ea..9aa886e2d70ea 100644
--- a/expression/aggregation/agg_to_pb_test.go
+++ b/expression/aggregation/agg_to_pb_test.go
@@ -36,7 +36,6 @@ func genColumn(tp byte, id int64) *expression.Column {
 }
 
 func TestAggFunc2Pb(t *testing.T) {
-	t.Parallel()
 	ctx := mock.NewContext()
 	client := new(mock.Client)
 
diff --git a/expression/aggregation/aggregation_test.go b/expression/aggregation/aggregation_test.go
index 8868c3d045ec5..9d32685af5a64 100644
--- a/expression/aggregation/aggregation_test.go
+++ b/expression/aggregation/aggregation_test.go
@@ -50,7 +50,6 @@ func createAggFuncSuite() (s *mockAggFuncSuite) {
 }
 
 func TestAvg(t *testing.T) {
-	t.Parallel()
 	s := createAggFuncSuite()
 	col := &expression.Column{
 		Index:   0,
@@ -95,7 +94,6 @@ func TestAvg(t *testing.T) {
 }
 
 func TestAvgFinalMode(t *testing.T) {
-	t.Parallel()
 	s := createAggFuncSuite()
 	rows := make([][]types.Datum, 0, 100)
 	for i := 1; i <= 100; i++ {
@@ -126,7 +124,6 @@ func TestAvgFinalMode(t *testing.T) {
 }
 
 func TestSum(t *testing.T) {
-	t.Parallel()
 	s := createAggFuncSuite()
 	col := &expression.Column{
 		Index:   0,
@@ -169,7 +166,6 @@ func TestSum(t *testing.T) {
 }
 
 func TestBitAnd(t *testing.T) {
-	t.Parallel()
 	s := createAggFuncSuite()
 	col := &expression.Column{
 		Index:   0,
@@ -249,7 +245,6 @@ func TestBitAnd(t *testing.T) {
 }
 
 func TestBitOr(t *testing.T) {
-	t.Parallel()
 	s := createAggFuncSuite()
 	col := &expression.Column{
 		Index:   0,
@@ -337,7 +332,6 @@ func TestBitOr(t *testing.T) {
 }
 
 func TestBitXor(t *testing.T) {
-	t.Parallel()
 	s := createAggFuncSuite()
 	col := &expression.Column{
 		Index:   0,
@@ -417,7 +411,6 @@ func TestBitXor(t *testing.T) {
 }
 
 func TestCount(t *testing.T) {
-	t.Parallel()
 	s := createAggFuncSuite()
 	col := &expression.Column{
 		Index:   0,
@@ -459,7 +452,6 @@ func TestCount(t *testing.T) {
 }
 
 func TestConcat(t *testing.T) {
-	t.Parallel()
 	s := createAggFuncSuite()
 	col := &expression.Column{
 		Index:   0,
@@ -517,7 +509,6 @@ func TestConcat(t *testing.T) {
 }
 
 func TestFirstRow(t *testing.T) {
-	t.Parallel()
 	s := createAggFuncSuite()
 	col := &expression.Column{
 		Index:   0,
@@ -546,7 +537,6 @@ func TestFirstRow(t *testing.T) {
 }
 
 func TestMaxMin(t *testing.T) {
-	t.Parallel()
 	s := createAggFuncSuite()
 	col := &expression.Column{
 		Index:   0,
diff --git a/expression/aggregation/util_test.go b/expression/aggregation/util_test.go
index 3b48271d51feb..3ac3720ffb714 100644
--- a/expression/aggregation/util_test.go
+++ b/expression/aggregation/util_test.go
@@ -24,7 +24,6 @@ import (
 )
 
 func TestDistinct(t *testing.T) {
-	t.Parallel()
 	sc := &stmtctx.StatementContext{TimeZone: time.Local}
 	dc := createDistinctChecker(sc)
 	testCases := []struct {
diff --git a/expression/bench_test.go b/expression/bench_test.go
index 6dcc68b8486f4..5bb0977841f1f 100644
--- a/expression/bench_test.go
+++ b/expression/bench_test.go
@@ -1502,8 +1502,6 @@ func testVectorizedBuiltinFunc(t *testing.T, vecExprCases vecExprBenchCases) {
 // testVectorizedBuiltinFuncForRand is used to verify that the vectorized
 // expression is evaluated correctly
 func testVectorizedBuiltinFuncForRand(t *testing.T, vecExprCases vecExprBenchCases) {
-	t.Parallel()
-
 	for funcName, testCases := range vecExprCases {
 		require.True(t, strings.EqualFold("rand", funcName))
 
diff --git a/expression/builtin_arithmetic_test.go b/expression/builtin_arithmetic_test.go
index 1848e42c31ef9..196caaf535efe 100644
--- a/expression/builtin_arithmetic_test.go
+++ b/expression/builtin_arithmetic_test.go
@@ -30,8 +30,6 @@ import (
 )
 
 func TestSetFlenDecimal4RealOrDecimal(t *testing.T) {
-	t.Parallel()
-
 	ret := &types.FieldType{}
 	a := &types.FieldType{
 		Decimal: 1,
@@ -96,7 +94,6 @@ func TestSetFlenDecimal4RealOrDecimal(t *testing.T) {
 }
 
 func TestArithmeticPlus(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	// case: 1
 	args := []interface{}{int64(12), int64(1)}
@@ -193,7 +190,6 @@ func TestArithmeticPlus(t *testing.T) {
 }
 
 func TestArithmeticMinus(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	// case: 1
 	args := []interface{}{int64(12), int64(1)}
@@ -272,7 +268,6 @@ func TestArithmeticMinus(t *testing.T) {
 }
 
 func TestArithmeticMultiply(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	testCases := []struct {
 		args   []interface{}
@@ -329,7 +324,6 @@ func TestArithmeticMultiply(t *testing.T) {
 }
 
 func TestArithmeticDivide(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 
 	testCases := []struct {
@@ -399,7 +393,6 @@ func TestArithmeticDivide(t *testing.T) {
 }
 
 func TestArithmeticIntDivide(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	testCases := []struct {
 		args   []interface{}
@@ -515,7 +508,6 @@ func TestArithmeticIntDivide(t *testing.T) {
 }
 
 func TestArithmeticMod(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	testCases := []struct {
 		args   []interface{}
@@ -668,7 +660,6 @@ func TestArithmeticMod(t *testing.T) {
 }
 
 func TestDecimalErrOverflow(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	testCases := []struct {
 		args   []float64
diff --git a/expression/builtin_cast_test.go b/expression/builtin_cast_test.go
index 73620773f5a81..0d60f9d8b6e3d 100644
--- a/expression/builtin_cast_test.go
+++ b/expression/builtin_cast_test.go
@@ -32,7 +32,6 @@ import (
 )
 
 func TestCastFunctions(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 
 	sc := ctx.GetSessionVars().StmtCtx
@@ -310,7 +309,6 @@ var (
 )
 
 func TestCastFuncSig(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 
 	sc := ctx.GetSessionVars().StmtCtx
@@ -1119,7 +1117,6 @@ func TestCastFuncSig(t *testing.T) {
 }
 
 func TestCastJSONAsDecimalSig(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	sc := ctx.GetSessionVars().StmtCtx
 	originIgnoreTruncate := sc.IgnoreTruncate
@@ -1166,7 +1163,6 @@ func TestCastJSONAsDecimalSig(t *testing.T) {
 
 // TestWrapWithCastAsTypesClasses tests WrapWithCastAsInt/Real/String/Decimal.
 func TestWrapWithCastAsTypesClasses(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 
 	durationColumn0 := &Column{RetType: types.NewFieldType(mysql.TypeDuration), Index: 0}
@@ -1309,7 +1305,6 @@ func TestWrapWithCastAsTypesClasses(t *testing.T) {
 }
 
 func TestWrapWithCastAsTime(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	sc := ctx.GetSessionVars().StmtCtx
 	save := sc.TimeZone
@@ -1364,7 +1359,6 @@ func TestWrapWithCastAsTime(t *testing.T) {
 }
 
 func TestWrapWithCastAsDuration(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 
 	cases := []struct {
@@ -1399,7 +1393,6 @@ func TestWrapWithCastAsDuration(t *testing.T) {
 }
 
 func TestWrapWithCastAsString(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 
 	cases := []struct {
@@ -1430,7 +1423,6 @@ func TestWrapWithCastAsString(t *testing.T) {
 }
 
 func TestWrapWithCastAsJSON(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 
 	input := &Column{RetType: &types.FieldType{Tp: mysql.TypeJSON}}
@@ -1442,8 +1434,6 @@ func TestWrapWithCastAsJSON(t *testing.T) {
 }
 
 func TestCastIntAsIntVec(t *testing.T) {
-	t.Parallel()
-
 	cast, input, result := genCastIntAsInt()
 	require.NoError(t, cast.vecEvalInt(input, result))
 	i64s := result.Int64s()
@@ -1472,8 +1462,6 @@ func TestCastIntAsIntVec(t *testing.T) {
 
 // for issue https://github.com/pingcap/tidb/issues/16825
 func TestCastStringAsDecimalSigWithUnsignedFlagInUnion(t *testing.T) {
-	t.Parallel()
-
 	col := &Column{RetType: types.NewFieldType(mysql.TypeString), Index: 0}
 	b, err := newBaseBuiltinFunc(mock.NewContext(), "", []Expression{col}, 0)
 	require.NoError(t, err)
diff --git a/expression/builtin_cast_vec_test.go b/expression/builtin_cast_vec_test.go
index 413977d2eaf65..5e647be3777dd 100644
--- a/expression/builtin_cast_vec_test.go
+++ b/expression/builtin_cast_vec_test.go
@@ -158,8 +158,6 @@ func TestVectorizedBuiltinCastFunc(t *testing.T) {
 }
 
 func TestVectorizedCastRealAsTime(t *testing.T) {
-	t.Parallel()
-
 	col := &Column{RetType: types.NewFieldType(mysql.TypeDouble), Index: 0}
 	baseFunc, err := newBaseBuiltinFunc(mock.NewContext(), "", []Expression{col}, 0)
 	if err != nil {
@@ -202,8 +200,6 @@ func genCastRealAsTime() *chunk.Chunk {
 
 // for issue https://github.com/pingcap/tidb/issues/16825
 func TestVectorizedCastStringAsDecimalWithUnsignedFlagInUnion(t *testing.T) {
-	t.Parallel()
-
 	col := &Column{RetType: types.NewFieldType(mysql.TypeString), Index: 0}
 	baseFunc, err := newBaseBuiltinFunc(mock.NewContext(), "", []Expression{col}, 0)
 	if err != nil {
diff --git a/expression/builtin_compare_test.go b/expression/builtin_compare_test.go
index c16f484c498dd..edc4b7e7ad056 100644
--- a/expression/builtin_compare_test.go
+++ b/expression/builtin_compare_test.go
@@ -29,7 +29,6 @@ import (
 )
 
 func TestCompareFunctionWithRefine(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 
 	tblInfo := newTestTableBuilder("").add("a", mysql.TypeLong, mysql.NotNullFlag).build()
@@ -84,7 +83,6 @@ func TestCompareFunctionWithRefine(t *testing.T) {
 }
 
 func TestCompare(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 
 	intVal, uintVal, realVal, stringVal, decimalVal := 1, uint64(1), 1.1, "123", types.NewDecFromFloatForTest(123.123)
@@ -170,7 +168,6 @@ func TestCompare(t *testing.T) {
 }
 
 func TestCoalesce(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 
 	cases := []struct {
@@ -216,7 +213,6 @@ func TestCoalesce(t *testing.T) {
 }
 
 func TestIntervalFunc(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 
 	sc := ctx.GetSessionVars().StmtCtx
@@ -274,7 +270,6 @@ func TestIntervalFunc(t *testing.T) {
 
 // greatest/least function is compatible with MySQL 8.0
 func TestGreatestLeastFunc(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	sc := ctx.GetSessionVars().StmtCtx
 	originIgnoreTruncate := sc.IgnoreTruncate
diff --git a/expression/builtin_control_test.go b/expression/builtin_control_test.go
index 6f149986b2cc6..c888e7f4e8dc6 100644
--- a/expression/builtin_control_test.go
+++ b/expression/builtin_control_test.go
@@ -27,7 +27,6 @@ import (
 )
 
 func TestCaseWhen(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	tbl := []struct {
 		Arg []interface{}
@@ -60,7 +59,6 @@ func TestCaseWhen(t *testing.T) {
 }
 
 func TestIf(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	stmtCtx := ctx.GetSessionVars().StmtCtx
 	origin := stmtCtx.IgnoreTruncate
@@ -109,7 +107,6 @@ func TestIf(t *testing.T) {
 }
 
 func TestIfNull(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	tbl := []struct {
 		arg1     interface{}
diff --git a/expression/builtin_encryption_test.go b/expression/builtin_encryption_test.go
index 58f7095bc4330..2dec9405f03db 100644
--- a/expression/builtin_encryption_test.go
+++ b/expression/builtin_encryption_test.go
@@ -55,7 +55,6 @@ var cryptTests = []struct {
 }
 
 func TestSQLDecode(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	for _, tt := range cryptTests {
 		err := ctx.GetSessionVars().SetSystemVar(variable.CharacterSetConnection, tt.chs)
@@ -75,7 +74,6 @@ func TestSQLDecode(t *testing.T) {
 }
 
 func TestSQLEncode(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	for _, test := range cryptTests {
 		err := ctx.GetSessionVars().SetSystemVar(variable.CharacterSetConnection, test.chs)
@@ -143,7 +141,6 @@ var aesTests = []struct {
 }
 
 func TestAESEncrypt(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 
 	fc := funcs[ast.AesEncrypt]
@@ -208,7 +205,6 @@ func TestAESEncrypt(t *testing.T) {
 }
 
 func TestAESDecrypt(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 
 	fc := funcs[ast.AesDecrypt]
@@ -339,7 +335,6 @@ func fromHex(str interface{}) (d types.Datum) {
 }
 
 func TestSha1Hash(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	sha1Tests := []struct {
 		chs    string
@@ -378,7 +373,6 @@ func TestSha1Hash(t *testing.T) {
 }
 
 func TestSha2Hash(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	sha2Tests := []struct {
 		chs        string
@@ -449,7 +443,6 @@ func TestSha2Hash(t *testing.T) {
 }
 
 func TestMD5Hash(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 
 	cases := []struct {
@@ -497,7 +490,6 @@ func TestMD5Hash(t *testing.T) {
 }
 
 func TestRandomBytes(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 
 	fc := funcs[ast.RandomBytes]
@@ -536,7 +528,6 @@ func decodeHex(str string) []byte {
 }
 
 func TestCompress(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	fc := funcs[ast.Compress]
 	tests := []struct {
@@ -569,7 +560,6 @@ func TestCompress(t *testing.T) {
 }
 
 func TestUncompress(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	tests := []struct {
 		in     interface{}
@@ -605,7 +595,6 @@ func TestUncompress(t *testing.T) {
 }
 
 func TestUncompressLength(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	tests := []struct {
 		in     interface{}
@@ -636,7 +625,6 @@ func TestUncompressLength(t *testing.T) {
 }
 
 func TestPassword(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	cases := []struct {
 		args     interface{}
diff --git a/expression/builtin_info_test.go b/expression/builtin_info_test.go
index b086d4c26ba0a..c6b730882c2e9 100644
--- a/expression/builtin_info_test.go
+++ b/expression/builtin_info_test.go
@@ -32,7 +32,6 @@ import (
 )
 
 func TestDatabase(t *testing.T) {
-	t.Parallel()
 	fc := funcs[ast.Database]
 	ctx := mock.NewContext()
 	f, err := fc.getFunction(ctx, nil)
@@ -58,7 +57,6 @@ func TestDatabase(t *testing.T) {
 }
 
 func TestFoundRows(t *testing.T) {
-	t.Parallel()
 	ctx := mock.NewContext()
 	sessionVars := ctx.GetSessionVars()
 	sessionVars.LastFoundRows = 2
@@ -72,7 +70,6 @@ func TestFoundRows(t *testing.T) {
 }
 
 func TestUser(t *testing.T) {
-	t.Parallel()
 	ctx := mock.NewContext()
 	sessionVars := ctx.GetSessionVars()
 	sessionVars.User = &auth.UserIdentity{Username: "root", Hostname: "localhost"}
@@ -87,7 +84,6 @@ func TestUser(t *testing.T) {
 }
 
 func TestCurrentUser(t *testing.T) {
-	t.Parallel()
 	ctx := mock.NewContext()
 	sessionVars := ctx.GetSessionVars()
 	sessionVars.User = &auth.UserIdentity{Username: "root", Hostname: "localhost", AuthUsername: "root", AuthHostname: "localhost"}
@@ -102,7 +98,6 @@ func TestCurrentUser(t *testing.T) {
 }
 
 func TestCurrentRole(t *testing.T) {
-	t.Parallel()
 	ctx := mock.NewContext()
 	fc := funcs[ast.CurrentRole]
 	f, err := fc.getFunction(ctx, nil)
@@ -128,7 +123,6 @@ func TestCurrentRole(t *testing.T) {
 }
 
 func TestConnectionID(t *testing.T) {
-	t.Parallel()
 	ctx := mock.NewContext()
 	sessionVars := ctx.GetSessionVars()
 	sessionVars.ConnectionID = uint64(1)
@@ -143,7 +137,6 @@ func TestConnectionID(t *testing.T) {
 }
 
 func TestVersion(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	fc := funcs[ast.Version]
 	f, err := fc.getFunction(ctx, nil)
@@ -155,7 +148,6 @@ func TestVersion(t *testing.T) {
 }
 
 func TestBenchMark(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	cases := []struct {
 		LoopCount  int
@@ -197,7 +189,6 @@ func TestBenchMark(t *testing.T) {
 }
 
 func TestCharset(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	fc := funcs[ast.Charset]
 	f, err := fc.getFunction(ctx, datumsToConstants(types.MakeDatums(nil)))
@@ -207,7 +198,6 @@ func TestCharset(t *testing.T) {
 }
 
 func TestCoercibility(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	fc := funcs[ast.Coercibility]
 	f, err := fc.getFunction(ctx, datumsToConstants(types.MakeDatums(nil)))
@@ -216,7 +206,6 @@ func TestCoercibility(t *testing.T) {
 }
 
 func TestCollation(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	fc := funcs[ast.Collation]
 	f, err := fc.getFunction(ctx, datumsToConstants(types.MakeDatums(nil)))
@@ -226,7 +215,6 @@ func TestCollation(t *testing.T) {
 }
 
 func TestRowCount(t *testing.T) {
-	t.Parallel()
 	ctx := mock.NewContext()
 	sessionVars := ctx.GetSessionVars()
 	sessionVars.StmtCtx.PrevAffectedRows = 10
@@ -246,7 +234,6 @@ func TestRowCount(t *testing.T) {
 
 // TestTiDBVersion for tidb_server().
 func TestTiDBVersion(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	f, err := newFunctionForTest(ctx, ast.TiDBVersion, primitiveValsToConstants(ctx, []interface{}{})...)
 	require.NoError(t, err)
@@ -256,7 +243,6 @@ func TestTiDBVersion(t *testing.T) {
 }
 
 func TestLastInsertID(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	maxUint64 := uint64(math.MaxUint64)
 	cases := []struct {
@@ -313,7 +299,6 @@ func TestLastInsertID(t *testing.T) {
 }
 
 func TestFormatBytes(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	tbl := []struct {
 		Arg interface{}
@@ -343,7 +328,6 @@ func TestFormatBytes(t *testing.T) {
 }
 
 func TestFormatNanoTime(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	tbl := []struct {
 		Arg interface{}
diff --git a/expression/builtin_json_test.go b/expression/builtin_json_test.go
index bdc6541c7a366..add185d57cc9a 100644
--- a/expression/builtin_json_test.go
+++ b/expression/builtin_json_test.go
@@ -29,7 +29,6 @@ import (
 )
 
 func TestJSONType(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	fc := funcs[ast.JSONType]
 	tbl := []struct {
@@ -55,7 +54,6 @@ func TestJSONType(t *testing.T) {
 }
 
 func TestJSONQuote(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	fc := funcs[ast.JSONQuote]
 	tbl := []struct {
@@ -85,7 +83,6 @@ func TestJSONQuote(t *testing.T) {
 }
 
 func TestJSONUnquote(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	fc := funcs[ast.JSONUnquote]
 	tbl := []struct {
@@ -126,7 +123,6 @@ func TestJSONUnquote(t *testing.T) {
 }
 
 func TestJSONExtract(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	fc := funcs[ast.JSONExtract]
 	jstr := `{"a": [{"aa": [{"aaa": 1}]}], "aaa": 2}`
@@ -165,7 +161,6 @@ func TestJSONExtract(t *testing.T) {
 
 // TestJSONSetInsertReplace tests grammar of json_{set,insert,replace}.
 func TestJSONSetInsertReplace(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	tbl := []struct {
 		fc           functionClass
@@ -212,7 +207,6 @@ func TestJSONSetInsertReplace(t *testing.T) {
 }
 
 func TestJSONMerge(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	fc := funcs[ast.JSONMerge]
 	tbl := []struct {
@@ -244,7 +238,6 @@ func TestJSONMerge(t *testing.T) {
 }
 
 func TestJSONMergePreserve(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	fc := funcs[ast.JSONMergePreserve]
 	tbl := []struct {
@@ -276,7 +269,6 @@ func TestJSONMergePreserve(t *testing.T) {
 }
 
 func TestJSONArray(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	fc := funcs[ast.JSONArray]
 	tbl := []struct {
@@ -302,7 +294,6 @@ func TestJSONArray(t *testing.T) {
 }
 
 func TestJSONObject(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	fc := funcs[ast.JSONObject]
 	tbl := []struct {
@@ -347,7 +338,6 @@ func TestJSONObject(t *testing.T) {
 }
 
 func TestJSONRemove(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	fc := funcs[ast.JSONRemove]
 	tbl := []struct {
@@ -398,7 +388,6 @@ func TestJSONRemove(t *testing.T) {
 }
 
 func TestJSONContains(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	fc := funcs[ast.JSONContains]
 	tbl := []struct {
@@ -479,7 +468,6 @@ func TestJSONContains(t *testing.T) {
 }
 
 func TestJSONContainsPath(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	fc := funcs[ast.JSONContainsPath]
 	jsonString := `{"a": 1, "b": 2, "c": {"d": 4}}`
@@ -539,7 +527,6 @@ func TestJSONContainsPath(t *testing.T) {
 }
 
 func TestJSONLength(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	fc := funcs[ast.JSONLength]
 	tbl := []struct {
@@ -612,7 +599,6 @@ func TestJSONLength(t *testing.T) {
 }
 
 func TestJSONKeys(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	fc := funcs[ast.JSONKeys]
 	tbl := []struct {
@@ -684,7 +670,6 @@ func TestJSONKeys(t *testing.T) {
 }
 
 func TestJSONDepth(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	fc := funcs[ast.JSONDepth]
 	tbl := []struct {
@@ -744,7 +729,6 @@ func TestJSONDepth(t *testing.T) {
 }
 
 func TestJSONArrayAppend(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	sampleJSON, err := json.ParseBinaryFromString(`{"b": 2}`)
 	require.NoError(t, err)
@@ -824,7 +808,6 @@ func TestJSONArrayAppend(t *testing.T) {
 }
 
 func TestJSONSearch(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	fc := funcs[ast.JSONSearch]
 	jsonString := `["abc", [{"k": "10"}, "def"], {"x":"abc"}, {"y":"bcd"}]`
@@ -900,7 +883,6 @@ func TestJSONSearch(t *testing.T) {
 }
 
 func TestJSONArrayInsert(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	fc := funcs[ast.JSONArrayInsert]
 	tbl := []struct {
@@ -974,7 +956,6 @@ func TestJSONArrayInsert(t *testing.T) {
 }
 
 func TestJSONValid(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	fc := funcs[ast.JSONValid]
 	tbl := []struct {
@@ -1006,7 +987,6 @@ func TestJSONValid(t *testing.T) {
 }
 
 func TestJSONStorageSize(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	fc := funcs[ast.JSONStorageSize]
 	tbl := []struct {
@@ -1050,7 +1030,6 @@ func TestJSONStorageSize(t *testing.T) {
 }
 
 func TestJSONPretty(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	fc := funcs[ast.JSONPretty]
 	tbl := []struct {
@@ -1125,7 +1104,6 @@ func TestJSONPretty(t *testing.T) {
 }
 
 func TestJSONMergePatch(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	fc := funcs[ast.JSONMergePatch]
 	tbl := []struct {
diff --git a/expression/builtin_like_test.go b/expression/builtin_like_test.go
index 46335adee253d..853e099d1d343 100644
--- a/expression/builtin_like_test.go
+++ b/expression/builtin_like_test.go
@@ -27,7 +27,6 @@ import (
 )
 
 func TestLike(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	tests := []struct {
 		input   string
@@ -62,7 +61,6 @@ func TestLike(t *testing.T) {
 }
 
 func TestRegexp(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	tests := []struct {
 		pattern string
diff --git a/expression/builtin_math_test.go b/expression/builtin_math_test.go
index 88d2985f10c17..898693d14b394 100644
--- a/expression/builtin_math_test.go
+++ b/expression/builtin_math_test.go
@@ -32,7 +32,6 @@ import (
 )
 
 func TestAbs(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	tbl := []struct {
 		Arg interface{}
@@ -59,7 +58,6 @@ func TestAbs(t *testing.T) {
 }
 
 func TestCeil(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	sc := ctx.GetSessionVars().StmtCtx
 	tmpIT := sc.IgnoreTruncate
@@ -125,7 +123,6 @@ func TestCeil(t *testing.T) {
 }
 
 func TestExp(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	tests := []struct {
 		args       interface{}
@@ -177,7 +174,6 @@ func TestExp(t *testing.T) {
 }
 
 func TestFloor(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	sc := ctx.GetSessionVars().StmtCtx
 	tmpIT := sc.IgnoreTruncate
@@ -248,7 +244,6 @@ func TestFloor(t *testing.T) {
 }
 
 func TestLog(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	tests := []struct {
 		args         []interface{}
@@ -292,7 +287,6 @@ func TestLog(t *testing.T) {
 }
 
 func TestLog2(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	tests := []struct {
 		args         interface{}
@@ -331,7 +325,6 @@ func TestLog2(t *testing.T) {
 }
 
 func TestLog10(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	tests := []struct {
 		args         interface{}
@@ -370,7 +363,6 @@ func TestLog10(t *testing.T) {
 }
 
 func TestRand(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	fc := funcs[ast.Rand]
 	f, err := fc.getFunction(ctx, nil)
@@ -392,7 +384,6 @@ func TestRand(t *testing.T) {
 }
 
 func TestPow(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	tbl := []struct {
 		Arg []interface{}
@@ -440,7 +431,6 @@ func TestPow(t *testing.T) {
 }
 
 func TestRound(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	newDec := types.NewDecFromStringForTest
 	tbl := []struct {
@@ -495,7 +485,6 @@ func TestRound(t *testing.T) {
 }
 
 func TestTruncate(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	newDec := types.NewDecFromStringForTest
 	tbl := []struct {
@@ -540,7 +529,6 @@ func TestTruncate(t *testing.T) {
 }
 
 func TestCRC32(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	tbl := []struct {
 		Arg []interface{}
@@ -568,7 +556,6 @@ func TestCRC32(t *testing.T) {
 }
 
 func TestConv(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	cases := []struct {
 		args     []interface{}
@@ -633,7 +620,6 @@ func TestConv(t *testing.T) {
 }
 
 func TestSign(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	sc := ctx.GetSessionVars().StmtCtx
 	tmpIT := sc.IgnoreTruncate
@@ -669,7 +655,6 @@ func TestSign(t *testing.T) {
 }
 
 func TestDegrees(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	sc := ctx.GetSessionVars().StmtCtx
 	sc.IgnoreTruncate = false
@@ -713,7 +698,6 @@ func TestDegrees(t *testing.T) {
 }
 
 func TestSqrt(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	tbl := []struct {
 		Arg []interface{}
@@ -738,7 +722,6 @@ func TestSqrt(t *testing.T) {
 }
 
 func TestPi(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	f, err := funcs[ast.PI].getFunction(ctx, nil)
 	require.NoError(t, err)
@@ -749,7 +732,6 @@ func TestPi(t *testing.T) {
 }
 
 func TestRadians(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	tbl := []struct {
 		Arg interface{}
@@ -783,7 +765,6 @@ func TestRadians(t *testing.T) {
 }
 
 func TestSin(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	cases := []struct {
 		args       interface{}
@@ -828,7 +809,6 @@ func TestSin(t *testing.T) {
 }
 
 func TestCos(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	cases := []struct {
 		args       interface{}
@@ -870,7 +850,6 @@ func TestCos(t *testing.T) {
 }
 
 func TestAcos(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	tests := []struct {
 		args       interface{}
@@ -910,7 +889,6 @@ func TestAcos(t *testing.T) {
 }
 
 func TestAsin(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	tests := []struct {
 		args       interface{}
@@ -950,7 +928,6 @@ func TestAsin(t *testing.T) {
 }
 
 func TestAtan(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	tests := []struct {
 		args       []interface{}
@@ -990,7 +967,6 @@ func TestAtan(t *testing.T) {
 }
 
 func TestTan(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	cases := []struct {
 		args       interface{}
@@ -1031,7 +1007,6 @@ func TestTan(t *testing.T) {
 }
 
 func TestCot(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	tests := []struct {
 		args   interface{}
diff --git a/expression/builtin_miscellaneous_test.go b/expression/builtin_miscellaneous_test.go
index 4de7136b29d14..f125c1b023df3 100644
--- a/expression/builtin_miscellaneous_test.go
+++ b/expression/builtin_miscellaneous_test.go
@@ -29,7 +29,6 @@ import (
 )
 
 func TestInetAton(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	tbl := []struct {
 		Input    interface{}
@@ -62,7 +61,6 @@ func TestInetAton(t *testing.T) {
 }
 
 func TestIsIPv4(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	tests := []struct {
 		ip     string
@@ -98,7 +96,6 @@ func TestIsIPv4(t *testing.T) {
 }
 
 func TestIsUUID(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	tests := []struct {
 		uuid   string
@@ -134,7 +131,6 @@ func TestIsUUID(t *testing.T) {
 }
 
 func TestUUID(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	f, err := newFunctionForTest(ctx, ast.UUID)
 	require.NoError(t, err)
@@ -161,7 +157,6 @@ func TestUUID(t *testing.T) {
 }
 
 func TestAnyValue(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	tbl := []struct {
 		arg interface{}
@@ -184,7 +179,6 @@ func TestAnyValue(t *testing.T) {
 }
 
 func TestIsIPv6(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	tests := []struct {
 		ip     string
@@ -214,7 +208,6 @@ func TestIsIPv6(t *testing.T) {
 }
 
 func TestInetNtoa(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	tests := []struct {
 		ip     int
@@ -245,7 +238,6 @@ func TestInetNtoa(t *testing.T) {
 }
 
 func TestInet6NtoA(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	tests := []struct {
 		ip     []byte
@@ -284,7 +276,6 @@ func TestInet6NtoA(t *testing.T) {
 }
 
 func TestInet6AtoN(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	tests := []struct {
 		ip     string
@@ -316,7 +307,6 @@ func TestInet6AtoN(t *testing.T) {
 }
 
 func TestIsIPv4Mapped(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	tests := []struct {
 		ip     []byte
@@ -346,7 +336,6 @@ func TestIsIPv4Mapped(t *testing.T) {
 }
 
 func TestIsIPv4Compat(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	tests := []struct {
 		ip     []byte
@@ -377,7 +366,6 @@ func TestIsIPv4Compat(t *testing.T) {
 }
 
 func TestNameConst(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	dec := types.NewDecFromFloatForTest(123.123)
 	tm := types.NewTime(types.FromGoTime(time.Now()), mysql.TypeDatetime, 6)
@@ -421,7 +409,6 @@ func TestNameConst(t *testing.T) {
 }
 
 func TestUUIDToBin(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	tests := []struct {
 		args       []interface{}
@@ -521,7 +508,6 @@ func TestUUIDToBin(t *testing.T) {
 }
 
 func TestBinToUUID(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	tests := []struct {
 		args       []interface{}
diff --git a/expression/builtin_op_test.go b/expression/builtin_op_test.go
index 93a750e341d4b..2e05b314d457c 100644
--- a/expression/builtin_op_test.go
+++ b/expression/builtin_op_test.go
@@ -28,7 +28,6 @@ import (
 )
 
 func TestUnary(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	cases := []struct {
 		args     interface{}
@@ -69,7 +68,6 @@ func TestUnary(t *testing.T) {
 }
 
 func TestLogicAnd(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	sc := ctx.GetSessionVars().StmtCtx
 	origin := sc.IgnoreTruncate
@@ -133,7 +131,6 @@ func TestLogicAnd(t *testing.T) {
 }
 
 func TestLeftShift(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	cases := []struct {
 		args     []interface{}
@@ -166,7 +163,6 @@ func TestLeftShift(t *testing.T) {
 }
 
 func TestRightShift(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	cases := []struct {
 		args     []interface{}
@@ -206,7 +202,6 @@ func TestRightShift(t *testing.T) {
 }
 
 func TestBitXor(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	cases := []struct {
 		args     []interface{}
@@ -246,7 +241,6 @@ func TestBitXor(t *testing.T) {
 }
 
 func TestBitOr(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	sc := ctx.GetSessionVars().StmtCtx
 	origin := sc.IgnoreTruncate
@@ -293,7 +287,6 @@ func TestBitOr(t *testing.T) {
 }
 
 func TestLogicOr(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	sc := ctx.GetSessionVars().StmtCtx
 	origin := sc.IgnoreTruncate
@@ -361,7 +354,6 @@ func TestLogicOr(t *testing.T) {
 }
 
 func TestBitAnd(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	cases := []struct {
 		args     []interface{}
@@ -401,7 +393,6 @@ func TestBitAnd(t *testing.T) {
 }
 
 func TestBitNeg(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	sc := ctx.GetSessionVars().StmtCtx
 	origin := sc.IgnoreTruncate
@@ -448,7 +439,6 @@ func TestBitNeg(t *testing.T) {
 }
 
 func TestUnaryNot(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	sc := ctx.GetSessionVars().StmtCtx
 	origin := sc.IgnoreTruncate
@@ -501,7 +491,6 @@ func TestUnaryNot(t *testing.T) {
 }
 
 func TestIsTrueOrFalse(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	sc := ctx.GetSessionVars().StmtCtx
 	origin := sc.IgnoreTruncate
@@ -609,7 +598,6 @@ func TestIsTrueOrFalse(t *testing.T) {
 }
 
 func TestLogicXor(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	sc := ctx.GetSessionVars().StmtCtx
 	origin := sc.IgnoreTruncate
diff --git a/expression/builtin_op_vec_test.go b/expression/builtin_op_vec_test.go
index 7003a6f1a7615..01b4ff2d0cc52 100644
--- a/expression/builtin_op_vec_test.go
+++ b/expression/builtin_op_vec_test.go
@@ -161,7 +161,6 @@ func BenchmarkVectorizedBuiltinOpFunc(b *testing.B) {
 }
 
 func TestBuiltinUnaryMinusIntSig(t *testing.T) {
-	t.Parallel()
 	ctx := mock.NewContext()
 	ft := eType2FieldType(types.ETInt)
 	col0 := &Column{RetType: ft, Index: 0}
diff --git a/expression/builtin_other_test.go b/expression/builtin_other_test.go
index 7b2471a208e02..e9f3bec61bc22 100644
--- a/expression/builtin_other_test.go
+++ b/expression/builtin_other_test.go
@@ -29,7 +29,6 @@ import (
 )
 
 func TestBitCount(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	stmtCtx := ctx.GetSessionVars().StmtCtx
 	origin := stmtCtx.IgnoreTruncate
@@ -76,7 +75,6 @@ func TestBitCount(t *testing.T) {
 }
 
 func TestRowFunc(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	fc := funcs[ast.RowFunc]
 	_, err := fc.getFunction(ctx, datumsToConstants(types.MakeDatums([]interface{}{"1", 1.2, true, 120}...)))
@@ -84,7 +82,6 @@ func TestRowFunc(t *testing.T) {
 }
 
 func TestSetVar(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	fc := funcs[ast.SetVar]
 	dec := types.NewDecFromInt(5)
@@ -120,7 +117,6 @@ func TestSetVar(t *testing.T) {
 }
 
 func TestGetVar(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	dec := types.NewDecFromInt(5)
 	timeDec := types.NewTime(types.FromGoTime(time.Now()), mysql.TypeTimestamp, 0)
@@ -175,7 +171,6 @@ func TestGetVar(t *testing.T) {
 }
 
 func TestValues(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	fc := &valuesFunctionClass{baseFunctionClass{ast.Values, 0, 0}, 1, types.NewFieldType(mysql.TypeVarchar)}
 	_, err := fc.getFunction(ctx, datumsToConstants(types.MakeDatums("")))
@@ -205,7 +200,6 @@ func TestValues(t *testing.T) {
 }
 
 func TestSetVarFromColumn(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	// Construct arguments.
 	argVarName := &Constant{
diff --git a/expression/builtin_other_vec_test.go b/expression/builtin_other_vec_test.go
index ed8658ee64129..4527838c4e981 100644
--- a/expression/builtin_other_vec_test.go
+++ b/expression/builtin_other_vec_test.go
@@ -63,7 +63,6 @@ func BenchmarkVectorizedBuiltinOtherFunc(b *testing.B) {
 }
 
 func TestInDecimal(t *testing.T) {
-	t.Parallel()
 	ctx := mock.NewContext()
 	ft := eType2FieldType(types.ETDecimal)
 	col0 := &Column{RetType: ft, Index: 0}
diff --git a/expression/builtin_regexp_vec_const_test.go b/expression/builtin_regexp_vec_const_test.go
index d82ad010be328..7362d148c35dd 100644
--- a/expression/builtin_regexp_vec_const_test.go
+++ b/expression/builtin_regexp_vec_const_test.go
@@ -61,7 +61,6 @@ func genVecBuiltinRegexpBenchCaseForConstants() (baseFunc builtinFunc, childrenF
 }
 
 func TestVectorizedBuiltinRegexpForConstants(t *testing.T) {
-	t.Parallel()
 	bf, childrenFieldTypes, input, output := genVecBuiltinRegexpBenchCaseForConstants()
 	err := bf.vecEvalInt(input, output)
 	require.NoError(t, err)
diff --git a/expression/builtin_string_test.go b/expression/builtin_string_test.go
index 54b98770b857c..475ba5b53bb74 100644
--- a/expression/builtin_string_test.go
+++ b/expression/builtin_string_test.go
@@ -38,7 +38,6 @@ import (
 )
 
 func TestLengthAndOctetLength(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	cases := []struct {
 		args     interface{}
@@ -107,7 +106,6 @@ func TestLengthAndOctetLength(t *testing.T) {
 }
 
 func TestASCII(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	cases := []struct {
 		args     interface{}
@@ -168,7 +166,6 @@ func TestASCII(t *testing.T) {
 }
 
 func TestConcat(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	cases := []struct {
 		args    []interface{}
@@ -225,7 +222,6 @@ func TestConcat(t *testing.T) {
 }
 
 func TestConcatSig(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	colTypes := []*types.FieldType{
 		{Tp: mysql.TypeVarchar},
@@ -271,7 +267,6 @@ func TestConcatSig(t *testing.T) {
 }
 
 func TestConcatWS(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	cases := []struct {
 		args     []interface{}
@@ -344,7 +339,6 @@ func TestConcatWS(t *testing.T) {
 }
 
 func TestConcatWSSig(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	colTypes := []*types.FieldType{
 		{Tp: mysql.TypeVarchar},
@@ -393,7 +387,6 @@ func TestConcatWSSig(t *testing.T) {
 }
 
 func TestLeft(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	stmtCtx := ctx.GetSessionVars().StmtCtx
 	origin := stmtCtx.IgnoreTruncate
@@ -444,7 +437,6 @@ func TestLeft(t *testing.T) {
 }
 
 func TestRight(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	stmtCtx := ctx.GetSessionVars().StmtCtx
 	origin := stmtCtx.IgnoreTruncate
@@ -495,7 +487,6 @@ func TestRight(t *testing.T) {
 }
 
 func TestRepeat(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	args := []interface{}{"a", int64(2)}
 	fc := funcs[ast.Repeat]
@@ -549,7 +540,6 @@ func TestRepeat(t *testing.T) {
 }
 
 func TestRepeatSig(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	colTypes := []*types.FieldType{
 		{Tp: mysql.TypeVarchar},
@@ -596,7 +586,6 @@ func TestRepeatSig(t *testing.T) {
 }
 
 func TestLower(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	cases := []struct {
 		args   []interface{}
@@ -655,7 +644,6 @@ func TestLower(t *testing.T) {
 }
 
 func TestUpper(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	cases := []struct {
 		args   []interface{}
@@ -715,7 +703,6 @@ func TestUpper(t *testing.T) {
 }
 
 func TestReverse(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	fc := funcs[ast.Reverse]
 	f, err := fc.getFunction(ctx, datumsToConstants(types.MakeDatums(nil)))
@@ -747,7 +734,6 @@ func TestReverse(t *testing.T) {
 }
 
 func TestStrcmp(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	cases := []struct {
 		args   []interface{}
@@ -789,7 +775,6 @@ func TestStrcmp(t *testing.T) {
 }
 
 func TestReplace(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	cases := []struct {
 		args   []interface{}
@@ -831,7 +816,6 @@ func TestReplace(t *testing.T) {
 }
 
 func TestSubstring(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	cases := []struct {
 		args   []interface{}
@@ -880,7 +864,6 @@ func TestSubstring(t *testing.T) {
 }
 
 func TestConvert(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	tbl := []struct {
 		str           interface{}
@@ -941,7 +924,6 @@ func TestConvert(t *testing.T) {
 }
 
 func TestSubstringIndex(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	cases := []struct {
 		args   []interface{}
@@ -989,7 +971,6 @@ func TestSubstringIndex(t *testing.T) {
 }
 
 func TestSpace(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	stmtCtx := ctx.GetSessionVars().StmtCtx
 	origin := stmtCtx.IgnoreTruncate
@@ -1036,7 +1017,6 @@ func TestSpace(t *testing.T) {
 }
 
 func TestSpaceSig(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	colTypes := []*types.FieldType{
 		{Tp: mysql.TypeLonglong},
@@ -1065,7 +1045,6 @@ func TestSpaceSig(t *testing.T) {
 }
 
 func TestLocate(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	// 1. Test LOCATE without binary input.
 	tbl := []struct {
@@ -1138,7 +1117,6 @@ func TestLocate(t *testing.T) {
 }
 
 func TestTrim(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	cases := []struct {
 		args   []interface{}
@@ -1191,7 +1169,6 @@ func TestTrim(t *testing.T) {
 }
 
 func TestLTrim(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	cases := []struct {
 		arg    interface{}
@@ -1234,7 +1211,6 @@ func TestLTrim(t *testing.T) {
 }
 
 func TestRTrim(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	cases := []struct {
 		arg    interface{}
@@ -1275,7 +1251,6 @@ func TestRTrim(t *testing.T) {
 }
 
 func TestHexFunc(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	cases := []struct {
 		arg    interface{}
@@ -1346,7 +1321,6 @@ func TestHexFunc(t *testing.T) {
 }
 
 func TestUnhexFunc(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	cases := []struct {
 		arg    interface{}
@@ -1387,7 +1361,6 @@ func TestUnhexFunc(t *testing.T) {
 }
 
 func TestBitLength(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	cases := []struct {
 		args     interface{}
@@ -1429,7 +1402,6 @@ func TestBitLength(t *testing.T) {
 }
 
 func TestChar(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	stmtCtx := ctx.GetSessionVars().StmtCtx
 	origin := stmtCtx.IgnoreTruncate
@@ -1473,7 +1445,6 @@ func TestChar(t *testing.T) {
 }
 
 func TestCharLength(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	tbl := []struct {
 		input  interface{}
@@ -1523,7 +1494,6 @@ func TestCharLength(t *testing.T) {
 }
 
 func TestFindInSet(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	for _, c := range []struct {
 		str    interface{}
@@ -1552,7 +1522,6 @@ func TestFindInSet(t *testing.T) {
 }
 
 func TestField(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	stmtCtx := ctx.GetSessionVars().StmtCtx
 	origin := stmtCtx.IgnoreTruncate
@@ -1588,7 +1557,6 @@ func TestField(t *testing.T) {
 }
 
 func TestLpad(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	tests := []struct {
 		str    string
@@ -1625,7 +1593,6 @@ func TestLpad(t *testing.T) {
 }
 
 func TestRpad(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	tests := []struct {
 		str    string
@@ -1662,7 +1629,6 @@ func TestRpad(t *testing.T) {
 }
 
 func TestRpadSig(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	colTypes := []*types.FieldType{
 		{Tp: mysql.TypeVarchar},
@@ -1705,7 +1671,6 @@ func TestRpadSig(t *testing.T) {
 }
 
 func TestInsertBinarySig(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	colTypes := []*types.FieldType{
 		{Tp: mysql.TypeVarchar},
@@ -1797,7 +1762,6 @@ func TestInsertBinarySig(t *testing.T) {
 }
 
 func TestInstr(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	tbl := []struct {
 		Args []interface{}
@@ -1843,7 +1807,6 @@ func TestInstr(t *testing.T) {
 }
 
 func TestLoadFile(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	cases := []struct {
 		arg    interface{}
@@ -1876,7 +1839,6 @@ func TestLoadFile(t *testing.T) {
 }
 
 func TestMakeSet(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	tbl := []struct {
 		argList []interface{}
@@ -1903,7 +1865,6 @@ func TestMakeSet(t *testing.T) {
 }
 
 func TestOct(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	octTests := []struct {
 		origin interface{}
@@ -1953,7 +1914,6 @@ func TestOct(t *testing.T) {
 }
 
 func TestFormat(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	formatTests := []struct {
 		number    interface{}
@@ -2083,7 +2043,6 @@ func TestFormat(t *testing.T) {
 }
 
 func TestFromBase64(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	tests := []struct {
 		args   interface{}
@@ -2129,7 +2088,6 @@ func TestFromBase64(t *testing.T) {
 }
 
 func TestFromBase64Sig(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	colTypes := []*types.FieldType{
 		{Tp: mysql.TypeVarchar},
@@ -2183,7 +2141,6 @@ func TestFromBase64Sig(t *testing.T) {
 }
 
 func TestInsert(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	tests := []struct {
 		args   []interface{}
@@ -2281,7 +2238,6 @@ func TestOrd(t *testing.T) {
 }
 
 func TestElt(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	tbl := []struct {
 		argLst []interface{}
@@ -2305,7 +2261,6 @@ func TestElt(t *testing.T) {
 }
 
 func TestExportSet(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	estd := []struct {
 		argLst []interface{}
@@ -2336,7 +2291,6 @@ func TestExportSet(t *testing.T) {
 }
 
 func TestBin(t *testing.T) {
-	t.Parallel()
 	tbl := []struct {
 		Input    interface{}
 		Expected interface{}
@@ -2368,7 +2322,6 @@ func TestBin(t *testing.T) {
 }
 
 func TestQuote(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	tbl := []struct {
 		arg interface{}
@@ -2398,7 +2351,6 @@ func TestQuote(t *testing.T) {
 }
 
 func TestToBase64(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	tests := []struct {
 		args   interface{}
@@ -2491,7 +2443,6 @@ func TestToBase64(t *testing.T) {
 }
 
 func TestToBase64Sig(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	colTypes := []*types.FieldType{
 		{Tp: mysql.TypeVarchar},
@@ -2561,7 +2512,6 @@ func TestToBase64Sig(t *testing.T) {
 }
 
 func TestStringRight(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	fc := funcs[ast.Right]
 	tests := []struct {
@@ -2594,7 +2544,6 @@ func TestStringRight(t *testing.T) {
 }
 
 func TestWeightString(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	fc := funcs[ast.WeightString]
 	tests := []struct {
@@ -2668,7 +2617,6 @@ func TestWeightString(t *testing.T) {
 }
 
 func TestTranslate(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	cases := []struct {
 		args  []interface{}
diff --git a/expression/builtin_test.go b/expression/builtin_test.go
index 79faddd2ffd3a..d5b59c359b700 100644
--- a/expression/builtin_test.go
+++ b/expression/builtin_test.go
@@ -122,7 +122,6 @@ func makeDatums(i interface{}) []types.Datum {
 }
 
 func TestIsNullFunc(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	fc := funcs[ast.IsNull]
 	f, err := fc.getFunction(ctx, datumsToConstants(types.MakeDatums(1)))
@@ -139,7 +138,6 @@ func TestIsNullFunc(t *testing.T) {
 }
 
 func TestLock(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	lock := funcs[ast.GetLock]
 	f, err := lock.getFunction(ctx, datumsToConstants(types.MakeDatums(nil, 1)))
@@ -157,7 +155,6 @@ func TestLock(t *testing.T) {
 }
 
 func TestDisplayName(t *testing.T) {
-	t.Parallel()
 	require.Equal(t, "=", GetDisplayName(ast.EQ))
 	require.Equal(t, "<=>", GetDisplayName(ast.NullEQ))
 	require.Equal(t, "IS TRUE", GetDisplayName(ast.IsTruthWithoutNull))
diff --git a/expression/builtin_time_test.go b/expression/builtin_time_test.go
index 7e41e0c8c549d..425fa976ae587 100644
--- a/expression/builtin_time_test.go
+++ b/expression/builtin_time_test.go
@@ -40,7 +40,6 @@ import (
 )
 
 func TestDate(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	tblDate := []struct {
 		Input  interface{}
@@ -418,7 +417,6 @@ func TestDate(t *testing.T) {
 }
 
 func TestMonthName(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	sc := ctx.GetSessionVars().StmtCtx
 	sc.IgnoreZeroInDate = true
@@ -455,7 +453,6 @@ func TestMonthName(t *testing.T) {
 }
 
 func TestDayName(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	sc := ctx.GetSessionVars().StmtCtx
 	sc.IgnoreZeroInDate = true
@@ -494,7 +491,6 @@ func TestDayName(t *testing.T) {
 }
 
 func TestDayOfWeek(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	sc := ctx.GetSessionVars().StmtCtx
 	sc.IgnoreZeroInDate = true
@@ -531,7 +527,6 @@ func TestDayOfWeek(t *testing.T) {
 }
 
 func TestDayOfMonth(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	sc := ctx.GetSessionVars().StmtCtx
 	sc.IgnoreZeroInDate = true
@@ -568,7 +563,6 @@ func TestDayOfMonth(t *testing.T) {
 }
 
 func TestDayOfYear(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	sc := ctx.GetSessionVars().StmtCtx
 	sc.IgnoreZeroInDate = true
@@ -605,7 +599,6 @@ func TestDayOfYear(t *testing.T) {
 }
 
 func TestDateFormat(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	// Test case for https://github.com/pingcap/tidb/issues/2908
 	// SELECT DATE_FORMAT(null,'%Y-%M-%D')
@@ -652,7 +645,6 @@ func TestDateFormat(t *testing.T) {
 }
 
 func TestClock(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	// test hour, minute, second, micro second
 
@@ -785,7 +777,6 @@ func TestClock(t *testing.T) {
 }
 
 func TestTime(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	cases := []struct {
 		args     interface{}
@@ -832,7 +823,6 @@ func resetStmtContext(ctx sessionctx.Context) {
 }
 
 func TestNowAndUTCTimestamp(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	gotime := func(typ types.Time, l *time.Location) time.Time {
 		tt, err := typ.GoTime(l)
@@ -899,7 +889,6 @@ func TestNowAndUTCTimestamp(t *testing.T) {
 }
 
 func TestIsDuration(t *testing.T) {
-	t.Parallel()
 	tbl := []struct {
 		Input  string
 		expect bool
@@ -921,7 +910,6 @@ func TestIsDuration(t *testing.T) {
 }
 
 func TestAddTimeSig(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	tbl := []struct {
 		Input         string
@@ -1037,7 +1025,6 @@ func TestAddTimeSig(t *testing.T) {
 }
 
 func TestSubTimeSig(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	tbl := []struct {
 		Input         string
@@ -1136,7 +1123,6 @@ func TestSubTimeSig(t *testing.T) {
 }
 
 func TestSysDate(t *testing.T) {
-	t.Parallel()
 	fc := funcs[ast.Sysdate]
 	ctx := mock.NewContext()
 	ctx.GetSessionVars().StmtCtx.TimeZone = timeutil.SystemLocation()
@@ -1241,7 +1227,6 @@ func builtinDateFormat(ctx sessionctx.Context, args []types.Datum) (d types.Datu
 }
 
 func TestFromUnixTime(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	tbl := []struct {
 		isDecimal      bool
@@ -1318,7 +1303,6 @@ func TestFromUnixTime(t *testing.T) {
 }
 
 func TestCurrentDate(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	last := time.Now()
 	fc := funcs[ast.CurrentDate]
@@ -1332,7 +1316,6 @@ func TestCurrentDate(t *testing.T) {
 }
 
 func TestCurrentTime(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	tfStr := "15:04:05"
 
@@ -1373,7 +1356,6 @@ func TestCurrentTime(t *testing.T) {
 }
 
 func TestUTCTime(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	last := time.Now().UTC()
 	tfStr := "00:00:00"
@@ -1415,7 +1397,6 @@ func TestUTCTime(t *testing.T) {
 }
 
 func TestUTCDate(t *testing.T) {
-	t.Parallel()
 	last := time.Now().UTC()
 	fc := funcs[ast.UTCDate]
 	f, err := fc.getFunction(mock.NewContext(), datumsToConstants(nil))
@@ -1428,7 +1409,6 @@ func TestUTCDate(t *testing.T) {
 }
 
 func TestStrToDate(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	// If you want to add test cases for `strToDate` but not the builtin function,
 	// adding cases in `types.format_test.go` `TestStrToDate` maybe more clear and easier
@@ -1501,7 +1481,6 @@ func TestStrToDate(t *testing.T) {
 }
 
 func TestFromDays(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	stmtCtx := ctx.GetSessionVars().StmtCtx
 	origin := stmtCtx.IgnoreTruncate
@@ -1563,7 +1542,6 @@ func TestFromDays(t *testing.T) {
 }
 
 func TestDateDiff(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	// Test cases from https://dev.mysql.com/doc/refman/5.7/en/date-and-time-functions.html#function_datediff
 	tests := []struct {
@@ -1617,7 +1595,6 @@ func TestDateDiff(t *testing.T) {
 }
 
 func TestTimeDiff(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	sc := ctx.GetSessionVars().StmtCtx
 	sc.IgnoreZeroInDate = true
@@ -1667,7 +1644,6 @@ func TestTimeDiff(t *testing.T) {
 }
 
 func TestWeek(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	// Test cases from https://dev.mysql.com/doc/refman/5.7/en/date-and-time-functions.html#function_week
 	tests := []struct {
@@ -1692,7 +1668,6 @@ func TestWeek(t *testing.T) {
 }
 
 func TestWeekWithoutModeSig(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	tests := []struct {
 		t      string
@@ -1723,7 +1698,6 @@ func TestWeekWithoutModeSig(t *testing.T) {
 	}
 }
 func TestYearWeek(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	sc := ctx.GetSessionVars().StmtCtx
 	sc.IgnoreZeroInDate = true
@@ -1755,7 +1729,6 @@ func TestYearWeek(t *testing.T) {
 }
 
 func TestTimestampDiff(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	tests := []struct {
 		unit   string
@@ -1804,7 +1777,6 @@ func TestTimestampDiff(t *testing.T) {
 }
 
 func TestUnixTimestamp(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	// Test UNIX_TIMESTAMP().
 	fc := funcs[ast.UnixTimestamp]
@@ -1895,7 +1867,6 @@ func TestUnixTimestamp(t *testing.T) {
 }
 
 func TestDateArithFuncs(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	date := []string{"2016-12-31", "2017-01-01"}
 	fcAdd := funcs[ast.DateAdd]
@@ -2132,7 +2103,6 @@ func TestDateArithFuncs(t *testing.T) {
 }
 
 func TestTimestamp(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	tests := []struct {
 		t      []types.Datum
@@ -2185,7 +2155,6 @@ func TestTimestamp(t *testing.T) {
 }
 
 func TestMakeDate(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	cases := []struct {
 		args     []interface{}
@@ -2240,7 +2209,6 @@ func TestMakeDate(t *testing.T) {
 }
 
 func TestMakeTime(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	tbl := []struct {
 		Args []interface{}
@@ -2351,7 +2319,6 @@ func TestMakeTime(t *testing.T) {
 }
 
 func TestQuarter(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	sc := ctx.GetSessionVars().StmtCtx
 	sc.IgnoreZeroInDate = true
@@ -2393,7 +2360,6 @@ func TestQuarter(t *testing.T) {
 }
 
 func TestGetFormat(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	tests := []struct {
 		unit     string
@@ -2432,7 +2398,6 @@ func TestGetFormat(t *testing.T) {
 }
 
 func TestToSeconds(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	sc := ctx.GetSessionVars().StmtCtx
 	sc.IgnoreZeroInDate = true
@@ -2474,7 +2439,6 @@ func TestToSeconds(t *testing.T) {
 }
 
 func TestToDays(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	sc := ctx.GetSessionVars().StmtCtx
 	sc.IgnoreZeroInDate = true
@@ -2517,7 +2481,6 @@ func TestToDays(t *testing.T) {
 }
 
 func TestTimestampAdd(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	tests := []struct {
 		unit     string
@@ -2544,7 +2507,6 @@ func TestTimestampAdd(t *testing.T) {
 }
 
 func TestPeriodAdd(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	tests := []struct {
 		Period  int64
@@ -2581,7 +2543,6 @@ func TestPeriodAdd(t *testing.T) {
 }
 
 func TestTimeFormat(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	// SELECT TIME_FORMAT(null,'%H %k %h %I %l')
 	args := []types.Datum{types.NewDatum(nil), types.NewStringDatum(`%H %k %h %I %l`)}
@@ -2620,7 +2581,6 @@ func TestTimeFormat(t *testing.T) {
 }
 
 func TestTimeToSec(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	fc := funcs[ast.TimeToSec]
 
@@ -2666,7 +2626,6 @@ func TestTimeToSec(t *testing.T) {
 }
 
 func TestSecToTime(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	stmtCtx := ctx.GetSessionVars().StmtCtx
 	origin := stmtCtx.IgnoreTruncate
@@ -2716,7 +2675,6 @@ func TestSecToTime(t *testing.T) {
 }
 
 func TestConvertTz(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	loc1, _ := time.LoadLocation("Europe/Tallinn")
 	loc2, _ := time.LoadLocation("Local")
@@ -2792,7 +2750,6 @@ func TestConvertTz(t *testing.T) {
 }
 
 func TestPeriodDiff(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	tests := []struct {
 		Period1 int64
@@ -2866,7 +2823,6 @@ func TestPeriodDiff(t *testing.T) {
 }
 
 func TestLastDay(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	tests := []struct {
 		param  interface{}
@@ -2922,7 +2878,6 @@ func TestLastDay(t *testing.T) {
 }
 
 func TestWithTimeZone(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	sv := ctx.GetSessionVars()
 	originTZ := sv.Location()
@@ -2967,7 +2922,6 @@ func TestWithTimeZone(t *testing.T) {
 }
 
 func TestTidbParseTso(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	ctx.GetSessionVars().TimeZone = time.UTC
 	tests := []struct {
@@ -3006,7 +2960,6 @@ func TestTidbParseTso(t *testing.T) {
 }
 
 func TestTiDBBoundedStaleness(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	t1, err := time.Parse(types.TimeFormat, "2015-09-21 09:53:04")
 	require.NoError(t, err)
@@ -3102,7 +3055,6 @@ func TestTiDBBoundedStaleness(t *testing.T) {
 }
 
 func TestGetIntervalFromDecimal(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	du := baseDateArithmetical{}
 
diff --git a/expression/builtin_time_vec_test.go b/expression/builtin_time_vec_test.go
index 2e2f3ba5a0db7..158fcbcc55ed2 100644
--- a/expression/builtin_time_vec_test.go
+++ b/expression/builtin_time_vec_test.go
@@ -589,7 +589,6 @@ func BenchmarkVectorizedBuiltinTimeFunc(b *testing.B) {
 }
 
 func TestVecMonth(t *testing.T) {
-	t.Parallel()
 	ctx := mock.NewContext()
 	ctx.GetSessionVars().SQLMode |= mysql.ModeNoZeroDate
 	ctx.GetSessionVars().StmtCtx.TruncateAsWarning = true
diff --git a/expression/collation_test.go b/expression/collation_test.go
index 1a8541fef3060..c7ff95961cef4 100644
--- a/expression/collation_test.go
+++ b/expression/collation_test.go
@@ -34,8 +34,6 @@ func newExpression(coercibility Coercibility, repertoire Repertoire, chs, coll s
 }
 
 func TestInferCollation(t *testing.T) {
-	t.Parallel()
-
 	tests := []struct {
 		exprs []Expression
 		err   bool
@@ -268,8 +266,6 @@ func newColInt(coercibility Coercibility) *Column {
 }
 
 func TestDeriveCollation(t *testing.T) {
-	t.Parallel()
-
 	ctx := mock.NewContext()
 	tests := []struct {
 		fcs    []string
diff --git a/expression/column_test.go b/expression/column_test.go
index da6eee5d6b0c2..f6fa04e784110 100644
--- a/expression/column_test.go
+++ b/expression/column_test.go
@@ -27,8 +27,6 @@ import (
 )
 
 func TestColumn(t *testing.T) {
-	t.Parallel()
-
 	ctx := mock.NewContext()
 	col := &Column{RetType: types.NewFieldType(mysql.TypeLonglong), UniqueID: 1}
 
@@ -100,8 +98,6 @@ func TestColumn(t *testing.T) {
 }
 
 func TestColumnHashCode(t *testing.T) {
-	t.Parallel()
-
 	col1 := &Column{
 		UniqueID: 12,
 	}
@@ -114,8 +110,6 @@ func TestColumnHashCode(t *testing.T) {
 }
 
 func TestColumn2Expr(t *testing.T) {
-	t.Parallel()
-
 	cols := make([]*Column, 0, 5)
 	for i := 0; i < 5; i++ {
 		cols = append(cols, &Column{UniqueID: int64(i)})
@@ -128,8 +122,6 @@ func TestColumn2Expr(t *testing.T) {
 }
 
 func TestColInfo2Col(t *testing.T) {
-	t.Parallel()
-
 	col0, col1 := &Column{ID: 0}, &Column{ID: 1}
 	cols := []*Column{col0, col1}
 	colInfo := &model.ColumnInfo{ID: 0}
@@ -142,8 +134,6 @@ func TestColInfo2Col(t *testing.T) {
 }
 
 func TestIndexInfo2Cols(t *testing.T) {
-	t.Parallel()
-
 	col0 := &Column{UniqueID: 0, ID: 0, RetType: types.NewFieldType(mysql.TypeLonglong)}
 	col1 := &Column{UniqueID: 1, ID: 1, RetType: types.NewFieldType(mysql.TypeLonglong)}
 	colInfo0 := &model.ColumnInfo{ID: 0, Name: model.NewCIStr("0")}
@@ -174,8 +164,6 @@ func TestIndexInfo2Cols(t *testing.T) {
 }
 
 func TestColHybird(t *testing.T) {
-	t.Parallel()
-
 	ctx := mock.NewContext()
 
 	// bit
diff --git a/expression/constant_fold_test.go b/expression/constant_fold_test.go
index d116da3916586..7ce440f33f2cd 100644
--- a/expression/constant_fold_test.go
+++ b/expression/constant_fold_test.go
@@ -21,8 +21,6 @@ import (
 )
 
 func TestFoldIfNull(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
diff --git a/expression/constant_propagation_test.go b/expression/constant_propagation_test.go
index ab88438623216..6ff6d31a6faad 100644
--- a/expression/constant_propagation_test.go
+++ b/expression/constant_propagation_test.go
@@ -23,8 +23,6 @@ import (
 )
 
 func TestOuterJoinPropConst(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
diff --git a/expression/constant_test.go b/expression/constant_test.go
index fc46c40f1072d..3b01be365121a 100644
--- a/expression/constant_test.go
+++ b/expression/constant_test.go
@@ -65,8 +65,6 @@ func newFunctionWithType(funcName string, tp *types.FieldType, args ...Expressio
 }
 
 func TestConstantPropagation(t *testing.T) {
-	t.Parallel()
-
 	tests := []struct {
 		solver     []PropagateConstantSolver
 		conditions []Expression
@@ -193,8 +191,6 @@ func TestConstantPropagation(t *testing.T) {
 }
 
 func TestConstantFolding(t *testing.T) {
-	t.Parallel()
-
 	tests := []struct {
 		condition Expression
 		result    string
@@ -231,7 +227,6 @@ func TestConstantFolding(t *testing.T) {
 }
 
 func TestConstantFoldingCharsetConvert(t *testing.T) {
-	t.Parallel()
 	tests := []struct {
 		condition Expression
 		result    string
@@ -288,8 +283,6 @@ func TestConstantFoldingCharsetConvert(t *testing.T) {
 }
 
 func TestDeferredParamNotNull(t *testing.T) {
-	t.Parallel()
-
 	ctx := mock.NewContext()
 	testTime := time.Now()
 	ctx.GetSessionVars().PreparedParams = []types.Datum{
@@ -356,8 +349,6 @@ func TestDeferredParamNotNull(t *testing.T) {
 }
 
 func TestDeferredExprNotNull(t *testing.T) {
-	t.Parallel()
-
 	m := &MockExpr{}
 	ctx := mock.NewContext()
 	cst := &Constant{DeferredExpr: m, RetType: newIntFieldType()}
@@ -433,8 +424,6 @@ func TestDeferredExprNotNull(t *testing.T) {
 }
 
 func TestVectorizedConstant(t *testing.T) {
-	t.Parallel()
-
 	// fixed-length type with/without Sel
 	for _, cst := range []*Constant{
 		{RetType: newIntFieldType(), Value: types.NewIntDatum(2333)},
@@ -490,8 +479,6 @@ func TestVectorizedConstant(t *testing.T) {
 }
 
 func TestGetTypeThreadSafe(t *testing.T) {
-	t.Parallel()
-
 	ctx := mock.NewContext()
 	ctx.GetSessionVars().PreparedParams = []types.Datum{
 		types.NewIntDatum(1),
diff --git a/expression/distsql_builtin_test.go b/expression/distsql_builtin_test.go
index 05337f806a4b8..6865eef4273f6 100644
--- a/expression/distsql_builtin_test.go
+++ b/expression/distsql_builtin_test.go
@@ -31,7 +31,6 @@ import (
 )
 
 func TestPBToExpr(t *testing.T) {
-	t.Parallel()
 	sc := new(stmtctx.StatementContext)
 	fieldTps := make([]*types.FieldType, 1)
 	ds := []types.Datum{types.NewIntDatum(1), types.NewUintDatum(1), types.NewFloat64Datum(1),
@@ -86,7 +85,6 @@ func TestPBToExpr(t *testing.T) {
 
 // TestEval test expr.Eval().
 func TestEval(t *testing.T) {
-	t.Parallel()
 	row := chunk.MutRowFromDatums([]types.Datum{types.NewDatum(100)}).ToRow()
 	fieldTps := make([]*types.FieldType, 1)
 	fieldTps[0] = types.NewFieldType(mysql.TypeLonglong)
diff --git a/expression/evaluator_test.go b/expression/evaluator_test.go
index ea35851acbe11..50a27f21f8d48 100644
--- a/expression/evaluator_test.go
+++ b/expression/evaluator_test.go
@@ -105,7 +105,6 @@ func primitiveValsToConstants(ctx sessionctx.Context, args []interface{}) []Expr
 }
 
 func TestSleep(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	sessVars := ctx.GetSessionVars()
 
@@ -171,7 +170,6 @@ func TestSleep(t *testing.T) {
 }
 
 func TestBinopComparison(t *testing.T) {
-	t.Parallel()
 	tbl := []struct {
 		lhs    interface{}
 		op     string
@@ -250,7 +248,6 @@ func TestBinopComparison(t *testing.T) {
 }
 
 func TestBinopLogic(t *testing.T) {
-	t.Parallel()
 	tbl := []struct {
 		lhs interface{}
 		op  string
@@ -290,7 +287,6 @@ func TestBinopLogic(t *testing.T) {
 }
 
 func TestBinopBitop(t *testing.T) {
-	t.Parallel()
 	tbl := []struct {
 		lhs interface{}
 		op  string
@@ -328,7 +324,6 @@ func TestBinopBitop(t *testing.T) {
 }
 
 func TestBinopNumeric(t *testing.T) {
-	t.Parallel()
 	tbl := []struct {
 		lhs interface{}
 		op  string
@@ -472,7 +467,6 @@ func TestBinopNumeric(t *testing.T) {
 }
 
 func TestExtract(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	str := "2011-11-11 10:10:10.123456"
 	tbl := []struct {
@@ -519,7 +513,6 @@ func TestExtract(t *testing.T) {
 }
 
 func TestUnaryOp(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	tbl := []struct {
 		arg    interface{}
@@ -588,7 +581,6 @@ func TestUnaryOp(t *testing.T) {
 }
 
 func TestMod(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	fc := funcs[ast.Mod]
 	f, err := fc.getFunction(ctx, datumsToConstants(types.MakeDatums(234, 10)))
diff --git a/expression/expr_to_pb_test.go b/expression/expr_to_pb_test.go
index 30cdf5599181b..414ef26f7ebdb 100644
--- a/expression/expr_to_pb_test.go
+++ b/expression/expr_to_pb_test.go
@@ -39,7 +39,6 @@ func genColumn(tp byte, id int64) *Column {
 
 func TestConstant2Pb(t *testing.T) {
 	t.Skip("constant pb has changed")
-	t.Parallel()
 	var constExprs []Expression
 	sc := new(stmtctx.StatementContext)
 	client := new(mock.Client)
@@ -123,7 +122,6 @@ func TestConstant2Pb(t *testing.T) {
 }
 
 func TestColumn2Pb(t *testing.T) {
-	t.Parallel()
 	var colExprs []Expression
 	sc := new(stmtctx.StatementContext)
 	client := new(mock.Client)
@@ -215,7 +213,6 @@ func TestColumn2Pb(t *testing.T) {
 }
 
 func TestCompareFunc2Pb(t *testing.T) {
-	t.Parallel()
 	var compareExprs = make([]Expression, 0)
 	sc := new(stmtctx.StatementContext)
 	client := new(mock.Client)
@@ -252,7 +249,6 @@ func TestCompareFunc2Pb(t *testing.T) {
 }
 
 func TestLikeFunc2Pb(t *testing.T) {
-	t.Parallel()
 	var likeFuncs []Expression
 	sc := new(stmtctx.StatementContext)
 	client := new(mock.Client)
@@ -291,7 +287,6 @@ func TestLikeFunc2Pb(t *testing.T) {
 }
 
 func TestArithmeticalFunc2Pb(t *testing.T) {
-	t.Parallel()
 	var arithmeticalFuncs = make([]Expression, 0)
 	sc := new(stmtctx.StatementContext)
 	client := new(mock.Client)
@@ -339,7 +334,6 @@ func TestArithmeticalFunc2Pb(t *testing.T) {
 }
 
 func TestDateFunc2Pb(t *testing.T) {
-	t.Parallel()
 	sc := new(stmtctx.StatementContext)
 	client := new(mock.Client)
 
@@ -396,7 +390,6 @@ func TestLogicalFunc2Pb(t *testing.T) {
 }
 
 func TestBitwiseFunc2Pb(t *testing.T) {
-	t.Parallel()
 	var bitwiseFuncs = make([]Expression, 0)
 	sc := new(stmtctx.StatementContext)
 	client := new(mock.Client)
@@ -435,7 +428,6 @@ func TestBitwiseFunc2Pb(t *testing.T) {
 }
 
 func TestControlFunc2Pb(t *testing.T) {
-	t.Parallel()
 	var controlFuncs = make([]Expression, 0)
 	sc := new(stmtctx.StatementContext)
 	client := new(mock.Client)
@@ -477,7 +469,6 @@ func TestControlFunc2Pb(t *testing.T) {
 }
 
 func TestOtherFunc2Pb(t *testing.T) {
-	t.Parallel()
 	var otherFuncs = make([]Expression, 0)
 	sc := new(stmtctx.StatementContext)
 	client := new(mock.Client)
@@ -508,7 +499,6 @@ func TestOtherFunc2Pb(t *testing.T) {
 }
 
 func TestExprPushDownToFlash(t *testing.T) {
-	t.Parallel()
 	sc := new(stmtctx.StatementContext)
 	client := new(mock.Client)
 
@@ -1004,7 +994,6 @@ func TestExprPushDownToFlash(t *testing.T) {
 
 func TestExprOnlyPushDownToFlash(t *testing.T) {
 	t.Skip("Skip this unstable test temporarily and bring it back before 2021-07-26")
-	t.Parallel()
 	sc := new(stmtctx.StatementContext)
 	client := new(mock.Client)
 
@@ -1058,7 +1047,6 @@ func TestExprOnlyPushDownToFlash(t *testing.T) {
 }
 
 func TestExprPushDownToTiKV(t *testing.T) {
-	t.Parallel()
 	sc := new(stmtctx.StatementContext)
 	client := new(mock.Client)
 
@@ -1111,7 +1099,6 @@ func TestExprPushDownToTiKV(t *testing.T) {
 }
 
 func TestExprOnlyPushDownToTiKV(t *testing.T) {
-	t.Parallel()
 	sc := new(stmtctx.StatementContext)
 	client := new(mock.Client)
 
@@ -1138,7 +1125,6 @@ func TestExprOnlyPushDownToTiKV(t *testing.T) {
 }
 
 func TestGroupByItem2Pb(t *testing.T) {
-	t.Parallel()
 	sc := new(stmtctx.StatementContext)
 	client := new(mock.Client)
 
@@ -1156,7 +1142,6 @@ func TestGroupByItem2Pb(t *testing.T) {
 }
 
 func TestSortByItem2Pb(t *testing.T) {
-	t.Parallel()
 	sc := new(stmtctx.StatementContext)
 	client := new(mock.Client)
 
diff --git a/expression/expression_test.go b/expression/expression_test.go
index 547b770b36932..0ae6cfdddd868 100644
--- a/expression/expression_test.go
+++ b/expression/expression_test.go
@@ -28,7 +28,6 @@ import (
 )
 
 func TestNewValuesFunc(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	res := NewValuesFunc(ctx, 0, types.NewFieldType(mysql.TypeLonglong))
 	require.Equal(t, "values", res.FuncName.O)
@@ -38,7 +37,6 @@ func TestNewValuesFunc(t *testing.T) {
 }
 
 func TestEvaluateExprWithNull(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	tblInfo := newTestTableBuilder("").add("col0", mysql.TypeLonglong, 0).add("col1", mysql.TypeLonglong, 0).build()
 	schema := tableInfoToSchemaForTest(tblInfo)
@@ -59,7 +57,6 @@ func TestEvaluateExprWithNull(t *testing.T) {
 }
 
 func TestEvaluateExprWithNullAndParameters(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	tblInfo := newTestTableBuilder("").add("col0", mysql.TypeLonglong, 0).build()
 	schema := tableInfoToSchemaForTest(tblInfo)
@@ -83,7 +80,6 @@ func TestEvaluateExprWithNullAndParameters(t *testing.T) {
 }
 
 func TestConstant(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	sc := &stmtctx.StatementContext{TimeZone: time.Local}
 	require.False(t, NewZero().IsCorrelated())
@@ -97,7 +93,6 @@ func TestConstant(t *testing.T) {
 }
 
 func TestIsBinaryLiteral(t *testing.T) {
-	t.Parallel()
 	col := &Column{RetType: types.NewFieldType(mysql.TypeEnum)}
 	require.False(t, IsBinaryLiteral(col))
 	col.RetType.Tp = mysql.TypeSet
@@ -114,7 +109,6 @@ func TestIsBinaryLiteral(t *testing.T) {
 }
 
 func TestConstItem(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	sf := newFunction(ast.Rand)
 	require.False(t, sf.ConstItem(ctx.GetSessionVars().StmtCtx))
@@ -127,7 +121,6 @@ func TestConstItem(t *testing.T) {
 }
 
 func TestVectorizable(t *testing.T) {
-	t.Parallel()
 	exprs := make([]Expression, 0, 4)
 	sf := newFunction(ast.Rand)
 	column := &Column{
@@ -227,7 +220,6 @@ func tableInfoToSchemaForTest(tableInfo *model.TableInfo) *Schema {
 }
 
 func TestEvalExpr(t *testing.T) {
-	t.Parallel()
 	ctx := createContext(t)
 	eTypes := []types.EvalType{types.ETInt, types.ETReal, types.ETDecimal, types.ETString, types.ETTimestamp, types.ETDatetime, types.ETDuration}
 	tNames := []string{"int", "real", "decimal", "string", "timestamp", "datetime", "duration"}
diff --git a/expression/flag_simplify_test.go b/expression/flag_simplify_test.go
index a3900f4a31149..c02cb7a1fa037 100644
--- a/expression/flag_simplify_test.go
+++ b/expression/flag_simplify_test.go
@@ -23,8 +23,6 @@ import (
 )
 
 func TestSimplifyExpressionByFlag(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
diff --git a/expression/function_traits_test.go b/expression/function_traits_test.go
index 6b859a4ec3d3a..703739ca10e5f 100644
--- a/expression/function_traits_test.go
+++ b/expression/function_traits_test.go
@@ -22,7 +22,6 @@ import (
 )
 
 func TestUnfoldableFuncs(t *testing.T) {
-	t.Parallel()
 	_, ok := unFoldableFunctions[ast.Sysdate]
 	require.True(t, ok)
 }
diff --git a/expression/helper_test.go b/expression/helper_test.go
index 84cc731f9878b..b7e00c221e141 100644
--- a/expression/helper_test.go
+++ b/expression/helper_test.go
@@ -33,8 +33,6 @@ import (
 )
 
 func TestGetTimeValue(t *testing.T) {
-	t.Parallel()
-
 	ctx := mock.NewContext()
 	v, err := GetTimeValue(ctx, "2012-12-12 00:00:00", mysql.TypeTimestamp, types.MinFsp)
 	require.NoError(t, err)
@@ -130,8 +128,6 @@ func TestGetTimeValue(t *testing.T) {
 }
 
 func TestIsCurrentTimestampExpr(t *testing.T) {
-	t.Parallel()
-
 	buildTimestampFuncCallExpr := func(i int64) *ast.FuncCallExpr {
 		var args []ast.ExprNode
 		if i != 0 {
@@ -157,8 +153,6 @@ func TestIsCurrentTimestampExpr(t *testing.T) {
 }
 
 func TestCurrentTimestampTimeZone(t *testing.T) {
-	t.Parallel()
-
 	ctx := mock.NewContext()
 	sessionVars := ctx.GetSessionVars()
 
diff --git a/expression/integration_test.go b/expression/integration_test.go
index 677b33d68a500..fa26348ab313a 100644
--- a/expression/integration_test.go
+++ b/expression/integration_test.go
@@ -54,8 +54,6 @@ import (
 )
 
 func Test19654(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -104,8 +102,6 @@ func Test19654(t *testing.T) {
 }
 
 func Test19387(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -122,8 +118,6 @@ func Test19387(t *testing.T) {
 }
 
 func TestFuncREPEAT(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -161,8 +155,6 @@ func TestFuncREPEAT(t *testing.T) {
 }
 
 func TestFuncLpadAndRpad(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -187,8 +179,6 @@ func TestFuncLpadAndRpad(t *testing.T) {
 }
 
 func TestBuiltinFuncJsonPretty(t *testing.T) {
-	t.Parallel()
-
 	ctx := context.Background()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
@@ -259,8 +249,6 @@ func TestBuiltinFuncJsonPretty(t *testing.T) {
 }
 
 func TestMiscellaneousBuiltin(t *testing.T) {
-	t.Parallel()
-
 	ctx := context.Background()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
@@ -344,8 +332,6 @@ func TestMiscellaneousBuiltin(t *testing.T) {
 }
 
 func TestConvertToBit(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -392,8 +378,6 @@ func TestConvertToBit(t *testing.T) {
 }
 
 func TestStringBuiltin(t *testing.T) {
-	t.Parallel()
-
 	t.Skip("it has been broken. Please fix it as soon as possible.")
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
@@ -830,8 +814,6 @@ func TestStringBuiltin(t *testing.T) {
 }
 
 func TestEncryptionBuiltin(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -999,8 +981,6 @@ func TestEncryptionBuiltin(t *testing.T) {
 }
 
 func TestOpBuiltin(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -1049,8 +1029,6 @@ func TestOpBuiltin(t *testing.T) {
 }
 
 func TestDatetimeOverflow(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -1090,8 +1068,6 @@ func TestDatetimeOverflow(t *testing.T) {
 }
 
 func TestIssue11648(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -1106,8 +1082,6 @@ func TestIssue11648(t *testing.T) {
 }
 
 func TestInfoBuiltin(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -1255,8 +1229,6 @@ func TestInfoBuiltin(t *testing.T) {
 }
 
 func TestControlBuiltin(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -1327,8 +1299,6 @@ func TestControlBuiltin(t *testing.T) {
 }
 
 func TestArithmeticBuiltin(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -1564,8 +1534,6 @@ func TestArithmeticBuiltin(t *testing.T) {
 }
 
 func TestGreatestTimeType(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -1606,8 +1574,6 @@ func TestGreatestTimeType(t *testing.T) {
 }
 
 func TestCompareBuiltin(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -1815,8 +1781,6 @@ func TestCompareBuiltin(t *testing.T) {
 
 // #23157: make sure if Nullif expr is correct combined with IsNull expr.
 func TestNullifWithIsNull(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -1830,8 +1794,6 @@ func TestNullifWithIsNull(t *testing.T) {
 }
 
 func TestAggregationBuiltin(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -1867,8 +1829,6 @@ func TestAggregationBuiltin(t *testing.T) {
 }
 
 func TestAggregationBuiltinBitOr(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -1896,8 +1856,6 @@ func TestAggregationBuiltinBitOr(t *testing.T) {
 }
 
 func TestAggregationBuiltinBitXor(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -1925,8 +1883,6 @@ func TestAggregationBuiltinBitXor(t *testing.T) {
 }
 
 func TestAggregationBuiltinBitAnd(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -1954,8 +1910,6 @@ func TestAggregationBuiltinBitAnd(t *testing.T) {
 }
 
 func TestAggregationBuiltinGroupConcat(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -1983,8 +1937,6 @@ func TestAggregationBuiltinGroupConcat(t *testing.T) {
 }
 
 func TestAggregationBuiltinJSONArrayagg(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -2027,8 +1979,6 @@ func TestAggregationBuiltinJSONArrayagg(t *testing.T) {
 }
 
 func TestAggregationBuiltinJSONObjectAgg(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -2069,8 +2019,6 @@ func TestAggregationBuiltinJSONObjectAgg(t *testing.T) {
 }
 
 func TestOtherBuiltin(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -2157,8 +2105,6 @@ func TestOtherBuiltin(t *testing.T) {
 }
 
 func TestDateBuiltin(t *testing.T) {
-	t.Parallel()
-
 	ctx := context.Background()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
@@ -2255,8 +2201,6 @@ func TestDateBuiltin(t *testing.T) {
 }
 
 func TestJSONBuiltin(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -2302,8 +2246,6 @@ func TestJSONBuiltin(t *testing.T) {
 }
 
 func TestTimeLiteral(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -2355,8 +2297,6 @@ func TestTimeLiteral(t *testing.T) {
 }
 
 func TestIssue13822(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -2366,8 +2306,6 @@ func TestIssue13822(t *testing.T) {
 }
 
 func TestTimestampLiteral(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -2399,8 +2337,6 @@ func TestTimestampLiteral(t *testing.T) {
 }
 
 func TestLiterals(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -2410,8 +2346,6 @@ func TestLiterals(t *testing.T) {
 }
 
 func TestFuncJSON(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -2599,8 +2533,6 @@ func TestFuncJSON(t *testing.T) {
 }
 
 func TestColumnInfoModified(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -2617,8 +2549,6 @@ func TestColumnInfoModified(t *testing.T) {
 }
 
 func TestIssues(t *testing.T) {
-	t.Parallel()
-
 	t.Skip("it has been broken. Please fix it as soon as possible.")
 	// for issue #4954
 	store, clean := testkit.CreateMockStore(t)
@@ -2681,8 +2611,6 @@ func TestIssues(t *testing.T) {
 }
 
 func TestInPredicate4UnsignedInt(t *testing.T) {
-	t.Parallel()
-
 	// for issue #6661
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
@@ -2708,8 +2636,6 @@ func TestInPredicate4UnsignedInt(t *testing.T) {
 }
 
 func TestFilterExtractFromDNF(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -2771,8 +2697,6 @@ func TestFilterExtractFromDNF(t *testing.T) {
 }
 
 func TestTiDBIsOwnerFunc(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -2788,8 +2712,6 @@ func TestTiDBIsOwnerFunc(t *testing.T) {
 }
 
 func TestTiDBDecodePlanFunc(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -2827,8 +2749,6 @@ func TestTiDBDecodePlanFunc(t *testing.T) {
 }
 
 func TestTiDBDecodeKeyFunc(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -2957,8 +2877,6 @@ func TestTiDBDecodeKeyFunc(t *testing.T) {
 }
 
 func TestTwoDecimalTruncate(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -2977,8 +2895,6 @@ func TestTwoDecimalTruncate(t *testing.T) {
 }
 
 func TestPrefixIndex(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -3012,8 +2928,6 @@ func TestPrefixIndex(t *testing.T) {
 }
 
 func TestDecimalMul(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -3026,8 +2940,6 @@ func TestDecimalMul(t *testing.T) {
 }
 
 func TestDecimalDiv(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -3038,8 +2950,6 @@ func TestDecimalDiv(t *testing.T) {
 }
 
 func TestUnknowHintIgnore(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -3053,8 +2963,6 @@ func TestUnknowHintIgnore(t *testing.T) {
 }
 
 func TestValuesInNonInsertStmt(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -3068,8 +2976,6 @@ func TestValuesInNonInsertStmt(t *testing.T) {
 }
 
 func TestForeignKeyVar(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -3080,8 +2986,6 @@ func TestForeignKeyVar(t *testing.T) {
 }
 
 func TestUserVarMockWindFunc(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -3158,8 +3062,6 @@ func TestUserVarMockWindFunc(t *testing.T) {
 }
 
 func TestCastAsTime(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -3193,8 +3095,6 @@ func TestCastAsTime(t *testing.T) {
 }
 
 func TestValuesFloat32(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -3209,8 +3109,6 @@ func TestValuesFloat32(t *testing.T) {
 }
 
 func TestFuncNameConst(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -3254,8 +3152,6 @@ func TestFuncNameConst(t *testing.T) {
 }
 
 func TestValuesEnum(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -3270,8 +3166,6 @@ func TestValuesEnum(t *testing.T) {
 }
 
 func TestIssue9325(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -3291,8 +3185,6 @@ func TestIssue9325(t *testing.T) {
 }
 
 func TestIssue9710(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -3326,8 +3218,6 @@ func TestIssue9710(t *testing.T) {
 
 // TestDecimalConvertToTime for issue #9770
 func TestDecimalConvertToTime(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -3341,8 +3231,6 @@ func TestDecimalConvertToTime(t *testing.T) {
 }
 
 func TestIssue9732(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -3376,8 +3264,6 @@ monthname(str_to_date(1, '%m')), monthname(str_to_date(0, '%m'));`).Check(testki
 }
 
 func TestDaynameArithmetic(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -3428,8 +3314,6 @@ func TestDaynameArithmetic(t *testing.T) {
 }
 
 func TestIssue10156(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -3454,8 +3338,6 @@ where
 }
 
 func TestIssue9727(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -3507,8 +3389,6 @@ func TestIssue9727(t *testing.T) {
 }
 
 func TestTimestampDatumEncode(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -3526,8 +3406,6 @@ func TestTimestampDatumEncode(t *testing.T) {
 }
 
 func TestDateTimeAddReal(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -3552,8 +3430,6 @@ func TestDateTimeAddReal(t *testing.T) {
 }
 
 func TestIssue10181(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -3566,8 +3442,6 @@ func TestIssue10181(t *testing.T) {
 }
 
 func TestExprPushdown(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -3612,8 +3486,6 @@ func TestExprPushdown(t *testing.T) {
 	tk.MustQuery("select count(id) from t use index(key2) where substr(col2, 1, 1) = '5' and substr(col1, 1, 1) = '4'").Check(testkit.Rows("1"))
 }
 func TestIssue16973(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -3642,8 +3514,6 @@ func TestIssue16973(t *testing.T) {
 }
 
 func TestExprPushdownBlacklist(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -3694,8 +3564,6 @@ func TestExprPushdownBlacklist(t *testing.T) {
 }
 
 func TestOptRuleBlacklist(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -3704,8 +3572,6 @@ func TestOptRuleBlacklist(t *testing.T) {
 }
 
 func TestIssue10804(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -3719,8 +3585,6 @@ func TestIssue10804(t *testing.T) {
 }
 
 func TestInvalidEndingStatement(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -3743,8 +3607,6 @@ func TestInvalidEndingStatement(t *testing.T) {
 }
 
 func TestIssue15613(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -3756,8 +3618,6 @@ func TestIssue15613(t *testing.T) {
 }
 
 func TestIssue10675(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -3791,8 +3651,6 @@ func TestIssue10675(t *testing.T) {
 }
 
 func TestDatetimeMicrosecond(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -3947,8 +3805,6 @@ func TestDatetimeMicrosecond(t *testing.T) {
 }
 
 func TestFuncCaseWithLeftJoin(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -3966,8 +3822,6 @@ func TestFuncCaseWithLeftJoin(t *testing.T) {
 }
 
 func TestIssue11594(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -3983,8 +3837,6 @@ func TestIssue11594(t *testing.T) {
 }
 
 func TestDefEnableVectorizedEvaluation(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -3994,8 +3846,6 @@ func TestDefEnableVectorizedEvaluation(t *testing.T) {
 }
 
 func TestIssue11309And11319(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -4046,8 +3896,6 @@ func TestIssue11309And11319(t *testing.T) {
 }
 
 func TestIssue12301(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -4059,8 +3907,6 @@ func TestIssue12301(t *testing.T) {
 }
 
 func TestIssue15315(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -4071,7 +3917,6 @@ func TestIssue15315(t *testing.T) {
 }
 
 func TestNotExistFunc(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -4099,8 +3944,6 @@ func TestNotExistFunc(t *testing.T) {
 }
 
 func TestDecodetoChunkReuse(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -4151,8 +3994,6 @@ func TestDecodetoChunkReuse(t *testing.T) {
 }
 
 func TestInMeetsPrepareAndExecute(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -4176,8 +4017,6 @@ func TestInMeetsPrepareAndExecute(t *testing.T) {
 }
 
 func TestCastStrToInt(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -4201,8 +4040,6 @@ func TestCastStrToInt(t *testing.T) {
 }
 
 func TestValuesForBinaryLiteral(t *testing.T) {
-	t.Parallel()
-
 	// See issue #15310
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
@@ -4221,8 +4058,6 @@ func TestValuesForBinaryLiteral(t *testing.T) {
 }
 
 func TestIssue14159(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -4235,8 +4070,6 @@ func TestIssue14159(t *testing.T) {
 }
 
 func TestIssue14146(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -4249,8 +4082,6 @@ func TestIssue14146(t *testing.T) {
 }
 
 func TestIssue15346(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -4261,8 +4092,6 @@ func TestIssue15346(t *testing.T) {
 }
 
 func TestOrderByFuncPlanCache(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -4288,8 +4117,6 @@ func TestOrderByFuncPlanCache(t *testing.T) {
 }
 
 func TestSelectLimitPlanCache(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -4325,8 +4152,6 @@ func TestSelectLimitPlanCache(t *testing.T) {
 }
 
 func TestCollation(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -4393,8 +4218,6 @@ func TestCollation(t *testing.T) {
 }
 
 func TestCoercibility(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -4436,8 +4259,6 @@ func TestCoercibility(t *testing.T) {
 }
 
 func TestIssue20071(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -4455,8 +4276,6 @@ func TestIssue20071(t *testing.T) {
 }
 
 func TestVirtualGeneratedColumnAndLimit(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -4470,8 +4289,6 @@ func TestVirtualGeneratedColumnAndLimit(t *testing.T) {
 }
 
 func TestIssue17791(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -4490,8 +4307,6 @@ func TestIssue17791(t *testing.T) {
 }
 
 func TestIssue15986(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -4526,8 +4341,6 @@ func TestIssue15986(t *testing.T) {
 }
 
 func TestNegativeZeroForHashJoin(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -4544,8 +4357,6 @@ func TestNegativeZeroForHashJoin(t *testing.T) {
 }
 
 func TestIssue1223(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -4601,8 +4412,6 @@ func TestIssue1223(t *testing.T) {
 }
 
 func TestIssue15743(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -4615,8 +4424,6 @@ func TestIssue15743(t *testing.T) {
 }
 
 func TestIssue15725(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -4630,8 +4437,6 @@ func TestIssue15725(t *testing.T) {
 }
 
 func TestIssue15790(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -4646,8 +4451,6 @@ func TestIssue15790(t *testing.T) {
 }
 
 func TestIssue15990(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -4663,8 +4466,6 @@ func TestIssue15990(t *testing.T) {
 }
 
 func TestIssue15992(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -4678,8 +4479,6 @@ func TestIssue15992(t *testing.T) {
 }
 
 func TestCTEWithDML(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -4709,8 +4508,6 @@ func TestCTEWithDML(t *testing.T) {
 }
 
 func TestIssue16419(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -4725,8 +4522,6 @@ func TestIssue16419(t *testing.T) {
 }
 
 func TestIssue16029(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -4743,8 +4538,6 @@ func TestIssue16029(t *testing.T) {
 }
 
 func TestIssue16426(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -4760,8 +4553,6 @@ func TestIssue16426(t *testing.T) {
 }
 
 func TestIssue16505(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -4777,8 +4568,6 @@ func TestIssue16505(t *testing.T) {
 }
 
 func TestIssue20121(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -4817,8 +4606,6 @@ func TestIssue20121(t *testing.T) {
 }
 
 func TestIssue16779(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -4832,8 +4619,6 @@ func TestIssue16779(t *testing.T) {
 }
 
 func TestIssue16697(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -4857,8 +4642,6 @@ func TestIssue16697(t *testing.T) {
 }
 
 func TestIssue17045(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -4872,8 +4655,6 @@ func TestIssue17045(t *testing.T) {
 }
 
 func TestIssue17098(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -4888,8 +4669,6 @@ func TestIssue17098(t *testing.T) {
 }
 
 func TestIssue17115(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -4899,8 +4678,6 @@ func TestIssue17115(t *testing.T) {
 }
 
 func TestIndexedVirtualGeneratedColumnTruncate(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -4935,8 +4712,6 @@ func TestIndexedVirtualGeneratedColumnTruncate(t *testing.T) {
 }
 
 func TestIssue17287(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -4965,8 +4740,6 @@ func TestIssue17287(t *testing.T) {
 }
 
 func TestIssue26989(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -4978,8 +4751,6 @@ func TestIssue26989(t *testing.T) {
 }
 
 func TestIssue17898(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -4993,8 +4764,6 @@ func TestIssue17898(t *testing.T) {
 }
 
 func TestIssue18515(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -5006,8 +4775,6 @@ func TestIssue18515(t *testing.T) {
 }
 
 func TestIssue20223(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -5028,8 +4795,6 @@ func TestIssue20223(t *testing.T) {
 }
 
 func TestIssue18525(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -5045,8 +4810,6 @@ func TestIssue18525(t *testing.T) {
 }
 
 func TestSchemaDMLNotChange(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -5064,8 +4827,6 @@ func TestSchemaDMLNotChange(t *testing.T) {
 }
 
 func TestIssue18850(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -5087,8 +4848,6 @@ func TestIssue18850(t *testing.T) {
 }
 
 func TestIssue19504(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -5107,8 +4866,6 @@ func TestIssue19504(t *testing.T) {
 }
 
 func TestIssue17767(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -5127,8 +4884,6 @@ func TestIssue17767(t *testing.T) {
 }
 
 func TestIssue19596(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -5143,8 +4898,6 @@ func TestIssue19596(t *testing.T) {
 }
 
 func TestIssue17476(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -5171,8 +4924,6 @@ func TestIssue17476(t *testing.T) {
 }
 
 func TestIssue11645(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -5190,8 +4941,6 @@ func TestIssue11645(t *testing.T) {
 }
 
 func TestIssue14349(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -5207,8 +4956,6 @@ func TestIssue14349(t *testing.T) {
 }
 
 func TestIssue20180(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -5231,8 +4978,6 @@ func TestIssue20180(t *testing.T) {
 }
 
 func TestIssue11755(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -5245,8 +4990,6 @@ func TestIssue11755(t *testing.T) {
 }
 
 func TestIssue20369(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -5260,8 +5003,6 @@ func TestIssue20369(t *testing.T) {
 }
 
 func TestIssue20730(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -5275,8 +5016,6 @@ func TestIssue20730(t *testing.T) {
 }
 
 func TestIssue20860(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -5289,8 +5028,6 @@ func TestIssue20860(t *testing.T) {
 }
 
 func TestIssue15847(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -5303,8 +5040,6 @@ func TestIssue15847(t *testing.T) {
 }
 
 func TestIssue10462(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -5345,8 +5080,6 @@ func TestIssue10462(t *testing.T) {
 }
 
 func TestIssue17868(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -5360,8 +5093,6 @@ func TestIssue17868(t *testing.T) {
 }
 
 func TestIssue21619(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -5375,8 +5106,6 @@ func TestIssue21619(t *testing.T) {
 }
 
 func TestIssue10467(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -5405,8 +5134,6 @@ func TestIssue10467(t *testing.T) {
 }
 
 func TestIssue19892(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -5648,8 +5375,6 @@ func TestIssue19892(t *testing.T) {
 
 // The actual results do not agree with the test results, It should be modified after the test suite is updated
 func TestIssue17726(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -5664,8 +5389,6 @@ func TestIssue17726(t *testing.T) {
 }
 
 func TestDatetimeUserVariable(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -5678,8 +5401,6 @@ func TestDatetimeUserVariable(t *testing.T) {
 }
 
 func TestIssue12205(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -5696,8 +5417,6 @@ func TestIssue12205(t *testing.T) {
 }
 
 func TestIssue21677(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -5719,8 +5438,6 @@ func TestIssue21677(t *testing.T) {
 }
 
 func TestIssue11333(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -5740,8 +5457,6 @@ func TestIssue11333(t *testing.T) {
 }
 
 func TestIssue12206(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -5756,8 +5471,6 @@ func TestIssue12206(t *testing.T) {
 }
 
 func TestCastCoer(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -5769,8 +5482,6 @@ func TestCastCoer(t *testing.T) {
 }
 
 func TestIssue12209(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -5785,8 +5496,6 @@ func TestIssue12209(t *testing.T) {
 }
 
 func TestIssue22098(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -5815,8 +5524,6 @@ func TestIssue22098(t *testing.T) {
 }
 
 func Test22717(t *testing.T) {
-	t.Parallel()
-
 	// For issue 22717
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
@@ -5841,8 +5548,6 @@ func Test22717(t *testing.T) {
 }
 
 func Test23262(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -5856,8 +5561,6 @@ func Test23262(t *testing.T) {
 }
 
 func TestClusteredIndexCorCol(t *testing.T) {
-	t.Parallel()
-
 	// For issue 23076
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
@@ -5873,8 +5576,6 @@ func TestClusteredIndexCorCol(t *testing.T) {
 }
 
 func TestEnumPushDown(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -5979,8 +5680,6 @@ func TestEnumPushDown(t *testing.T) {
 }
 
 func TestJiraSetInnoDBDefaultRowFormat(t *testing.T) {
-	t.Parallel()
-
 	// For issue #23541
 	// JIRA needs to be able to set this to be happy.
 	// See: https://nova.moe/run-jira-on-tidb/
@@ -5998,8 +5697,6 @@ func TestJiraSetInnoDBDefaultRowFormat(t *testing.T) {
 }
 
 func TestIssue23623(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -6012,8 +5709,6 @@ func TestIssue23623(t *testing.T) {
 }
 
 func TestApproximatePercentile(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -6026,8 +5721,6 @@ func TestApproximatePercentile(t *testing.T) {
 }
 
 func TestIssue24429(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -6042,8 +5735,6 @@ func TestIssue24429(t *testing.T) {
 }
 
 func TestVitessHash(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -6075,8 +5766,6 @@ func TestVitessHash(t *testing.T) {
 }
 
 func TestVitessHashMatchesVitessShards(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -6122,8 +5811,6 @@ func TestVitessHashMatchesVitessShards(t *testing.T) {
 }
 
 func TestSecurityEnhancedMode(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -6138,8 +5825,6 @@ func TestSecurityEnhancedMode(t *testing.T) {
 }
 
 func TestIssue23925(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -6158,8 +5843,6 @@ func TestIssue23925(t *testing.T) {
 }
 
 func TestCTEInvalidUsage(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -6204,8 +5887,6 @@ func TestCTEInvalidUsage(t *testing.T) {
 }
 
 func TestIssue23889(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -6222,8 +5903,6 @@ func TestIssue23889(t *testing.T) {
 }
 
 func TestRefineArgNullValues(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -6240,8 +5919,6 @@ func TestRefineArgNullValues(t *testing.T) {
 }
 
 func TestEnumIndex(t *testing.T) {
-	t.Parallel()
-
 	elems := []string{"\"a\"", "\"b\"", "\"c\""}
 	rand.Shuffle(len(elems), func(i, j int) {
 		elems[i], elems[j] = elems[j], elems[i]
@@ -6338,8 +6015,6 @@ func TestEnumIndex(t *testing.T) {
 // Previously global values were cached. This is incorrect.
 // See: https://github.com/pingcap/tidb/issues/24368
 func TestGlobalCacheCorrectness(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -6352,8 +6027,6 @@ func TestGlobalCacheCorrectness(t *testing.T) {
 }
 
 func TestRedundantColumnResolve(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -6386,8 +6059,6 @@ func TestRedundantColumnResolve(t *testing.T) {
 }
 
 func TestControlFunctionWithEnumOrSet(t *testing.T) {
-	t.Parallel()
-
 	// issue 23114
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
@@ -6488,8 +6159,6 @@ func TestControlFunctionWithEnumOrSet(t *testing.T) {
 }
 
 func TestComplexShowVariables(t *testing.T) {
-	t.Parallel()
-
 	// This is an example SHOW VARIABLES from mysql-connector-java-5.1.34
 	// It returns 19 rows in MySQL 5.7 (the language sysvar no longer exists in 5.6+)
 	// and 16 rows in MySQL 8.0 (the aliases for tx_isolation is removed, along with query cache)
@@ -6510,8 +6179,6 @@ OR Variable_name = 'license' OR Variable_name = 'init_connect'`).Rows(), 19)
 }
 
 func TestBuiltinFuncJSONMergePatch_InColumn(t *testing.T) {
-	t.Parallel()
-
 	ctx := context.Background()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
@@ -6583,8 +6250,6 @@ func TestBuiltinFuncJSONMergePatch_InColumn(t *testing.T) {
 }
 
 func TestBuiltinFuncJSONMergePatch_InExpression(t *testing.T) {
-	t.Parallel()
-
 	ctx := context.Background()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
@@ -6706,8 +6371,6 @@ func TestBuiltinFuncJSONMergePatch_InExpression(t *testing.T) {
 }
 
 func TestFloat64Inf(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -6719,8 +6382,6 @@ func TestFloat64Inf(t *testing.T) {
 }
 
 func TestCharsetErr(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -6735,8 +6396,6 @@ func TestCharsetErr(t *testing.T) {
 }
 
 func TestIssue25591(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -6759,8 +6418,6 @@ func TestIssue25591(t *testing.T) {
 }
 
 func TestIssue25526(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -6777,8 +6434,6 @@ func TestIssue25526(t *testing.T) {
 }
 
 func TestTimestampIssue25093(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -6796,8 +6451,6 @@ func TestTimestampIssue25093(t *testing.T) {
 }
 
 func TestIssue24953(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -6812,8 +6465,6 @@ func TestIssue24953(t *testing.T) {
 
 // issue https://github.com/pingcap/tidb/issues/26111
 func TestRailsFKUsage(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -6850,8 +6501,6 @@ func TestRailsFKUsage(t *testing.T) {
 }
 
 func TestTranslate(t *testing.T) {
-	t.Parallel()
-
 	cases := []string{"'ABC'", "'AABC'", "'A.B.C'", "'aaaaabbbbb'", "'abc'", "'aaa'", "NULL"}
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
@@ -6889,8 +6538,6 @@ func TestTranslate(t *testing.T) {
 }
 
 func TestIssue26958(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -6907,8 +6554,6 @@ func TestIssue26958(t *testing.T) {
 }
 
 func TestConstPropNullFunctions(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -6930,8 +6575,6 @@ func TestConstPropNullFunctions(t *testing.T) {
 }
 
 func TestIssue27233(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -6945,8 +6588,6 @@ func TestIssue27233(t *testing.T) {
 }
 
 func TestIssue27236(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -6963,8 +6604,6 @@ func TestIssue27236(t *testing.T) {
 }
 
 func TestIssue26977(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -6974,8 +6613,6 @@ func TestIssue26977(t *testing.T) {
 }
 
 func TestIssue27610(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -6989,8 +6626,6 @@ func TestIssue27610(t *testing.T) {
 }
 
 func TestLastInsertId(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -7008,8 +6643,6 @@ func TestLastInsertId(t *testing.T) {
 }
 
 func TestTimestamp(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -7060,8 +6693,6 @@ func TestTimestamp(t *testing.T) {
 }
 
 func TestIdentity(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -7079,8 +6710,6 @@ func TestIdentity(t *testing.T) {
 }
 
 func TestIssue28804(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -7107,8 +6736,6 @@ PARTITION p20210909 VALUES LESS THAN (1631203200)
 }
 
 func TestIssue28643(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -7125,8 +6752,6 @@ func TestIssue28643(t *testing.T) {
 }
 
 func TestIssue27831(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -7144,8 +6769,6 @@ func TestIssue27831(t *testing.T) {
 }
 
 func TestIssue29434(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -7167,8 +6790,6 @@ func TestIssue29434(t *testing.T) {
 }
 
 func TestIssue29417(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -7181,8 +6802,6 @@ func TestIssue29417(t *testing.T) {
 }
 
 func TestIssue29244(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -7199,8 +6818,6 @@ func TestIssue29244(t *testing.T) {
 }
 
 func TestIssue29513(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -7217,8 +6834,6 @@ func TestIssue29513(t *testing.T) {
 }
 
 func TestIssue29755(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -7234,8 +6849,6 @@ func TestIssue29755(t *testing.T) {
 }
 
 func TestIssue30101(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -7248,8 +6861,6 @@ func TestIssue30101(t *testing.T) {
 }
 
 func TestIssue28739(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -7272,8 +6883,6 @@ func TestIssue28739(t *testing.T) {
 }
 
 func TestIssue30326(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
diff --git a/expression/scalar_function_test.go b/expression/scalar_function_test.go
index 827cc63af6060..07454f861431a 100644
--- a/expression/scalar_function_test.go
+++ b/expression/scalar_function_test.go
@@ -28,8 +28,6 @@ import (
 )
 
 func TestScalarFunction(t *testing.T) {
-	t.Parallel()
-
 	ctx := mock.NewContext()
 	a := &Column{
 		UniqueID: 1,
@@ -57,8 +55,6 @@ func TestScalarFunction(t *testing.T) {
 }
 
 func TestIssue23309(t *testing.T) {
-	t.Parallel()
-
 	a := &Column{
 		UniqueID: 1,
 		RetType:  types.NewFieldType(mysql.TypeDouble),
@@ -74,8 +70,6 @@ func TestIssue23309(t *testing.T) {
 }
 
 func TestScalarFuncs2Exprs(t *testing.T) {
-	t.Parallel()
-
 	ctx := mock.NewContext()
 	a := &Column{
 		UniqueID: 1,
diff --git a/expression/schema_test.go b/expression/schema_test.go
index 88fe7d199dd96..6ee4dc35b1853 100644
--- a/expression/schema_test.go
+++ b/expression/schema_test.go
@@ -48,7 +48,6 @@ func (s *schemaGenerator) generateSchema(colCount int) *Schema {
 }
 
 func TestSchemaString(t *testing.T) {
-	t.Parallel()
 	s := &schemaGenerator{}
 	schema := s.generateSchema(5)
 	require.Equal(t, "Column: [Column#1,Column#2,Column#3,Column#4,Column#5] Unique key: []", schema.String())
@@ -57,7 +56,6 @@ func TestSchemaString(t *testing.T) {
 }
 
 func TestSchemaRetrieveColumn(t *testing.T) {
-	t.Parallel()
 	s := &schemaGenerator{}
 	schema := s.generateSchema(5)
 	colOutSchema := &Column{
@@ -70,7 +68,6 @@ func TestSchemaRetrieveColumn(t *testing.T) {
 }
 
 func TestSchemaIsUniqueKey(t *testing.T) {
-	t.Parallel()
 	s := &schemaGenerator{}
 	schema := s.generateSchema(5)
 	generateKeys4Schema(schema)
@@ -88,7 +85,6 @@ func TestSchemaIsUniqueKey(t *testing.T) {
 }
 
 func TestSchemaContains(t *testing.T) {
-	t.Parallel()
 	s := &schemaGenerator{}
 	schema := s.generateSchema(5)
 	colOutSchema := &Column{
@@ -101,7 +97,6 @@ func TestSchemaContains(t *testing.T) {
 }
 
 func TestSchemaColumnsIndices(t *testing.T) {
-	t.Parallel()
 	s := &schemaGenerator{}
 	schema := s.generateSchema(5)
 	colOutSchema := &Column{
@@ -117,7 +112,6 @@ func TestSchemaColumnsIndices(t *testing.T) {
 }
 
 func TestSchemaColumnsByIndices(t *testing.T) {
-	t.Parallel()
 	s := &schemaGenerator{}
 	schema := s.generateSchema(5)
 	indices := []int{0, 1, 2, 3}
@@ -128,7 +122,6 @@ func TestSchemaColumnsByIndices(t *testing.T) {
 }
 
 func TestSchemaMergeSchema(t *testing.T) {
-	t.Parallel()
 	s := &schemaGenerator{}
 	lSchema := s.generateSchema(5)
 	generateKeys4Schema(lSchema)
@@ -150,7 +143,6 @@ func TestSchemaMergeSchema(t *testing.T) {
 }
 
 func TestGetUsedList(t *testing.T) {
-	t.Parallel()
 	s := &schemaGenerator{}
 	schema := s.generateSchema(5)
 	var usedCols []*Column
diff --git a/expression/typeinfer_test.go b/expression/typeinfer_test.go
index af92f305943ab..b0f6508b33481 100644
--- a/expression/typeinfer_test.go
+++ b/expression/typeinfer_test.go
@@ -34,8 +34,6 @@ import (
 )
 
 func TestInferType(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
diff --git a/expression/util_test.go b/expression/util_test.go
index 75e6b9c67113f..5ad6331863db2 100644
--- a/expression/util_test.go
+++ b/expression/util_test.go
@@ -33,7 +33,6 @@ import (
 )
 
 func TestBaseBuiltin(t *testing.T) {
-	t.Parallel()
 	ctx := mock.NewContext()
 	bf, err := newBaseBuiltinFuncWithTp(ctx, "", nil, types.ETTimestamp)
 	require.NoError(t, err)
@@ -54,7 +53,6 @@ func TestBaseBuiltin(t *testing.T) {
 }
 
 func TestClone(t *testing.T) {
-	t.Parallel()
 	builtinFuncs := []builtinFunc{
 		&builtinArithmeticPlusRealSig{}, &builtinArithmeticPlusDecimalSig{}, &builtinArithmeticPlusIntSig{}, &builtinArithmeticMinusRealSig{}, &builtinArithmeticMinusDecimalSig{},
 		&builtinArithmeticMinusIntSig{}, &builtinArithmeticDivideRealSig{}, &builtinArithmeticDivideDecimalSig{}, &builtinArithmeticMultiplyRealSig{}, &builtinArithmeticMultiplyDecimalSig{},
@@ -161,7 +159,6 @@ func TestClone(t *testing.T) {
 }
 
 func TestGetUint64FromConstant(t *testing.T) {
-	t.Parallel()
 	con := &Constant{
 		Value: types.NewDatum(nil),
 	}
@@ -199,7 +196,6 @@ func TestGetUint64FromConstant(t *testing.T) {
 }
 
 func TestSetExprColumnInOperand(t *testing.T) {
-	t.Parallel()
 	col := &Column{RetType: newIntFieldType()}
 	require.True(t, setExprColumnInOperand(col).(*Column).InOperand)
 
@@ -211,7 +207,6 @@ func TestSetExprColumnInOperand(t *testing.T) {
 }
 
 func TestPopRowFirstArg(t *testing.T) {
-	t.Parallel()
 	c1, c2, c3 := &Column{RetType: newIntFieldType()}, &Column{RetType: newIntFieldType()}, &Column{RetType: newIntFieldType()}
 	f, err := funcs[ast.RowFunc].getFunction(mock.NewContext(), []Expression{c1, c2, c3})
 	require.NoError(t, err)
@@ -222,7 +217,6 @@ func TestPopRowFirstArg(t *testing.T) {
 }
 
 func TestGetStrIntFromConstant(t *testing.T) {
-	t.Parallel()
 	col := &Column{}
 	_, _, err := GetStringFromConstant(mock.NewContext(), col)
 	require.Error(t, err)
@@ -250,7 +244,6 @@ func TestGetStrIntFromConstant(t *testing.T) {
 }
 
 func TestSubstituteCorCol2Constant(t *testing.T) {
-	t.Parallel()
 	ctx := mock.NewContext()
 	corCol1 := &CorrelatedColumn{Data: &NewOne().Value}
 	corCol1.RetType = types.NewFieldType(mysql.TypeLonglong)
@@ -276,7 +269,6 @@ func TestSubstituteCorCol2Constant(t *testing.T) {
 }
 
 func TestPushDownNot(t *testing.T) {
-	t.Parallel()
 	ctx := mock.NewContext()
 	col := &Column{Index: 1, RetType: types.NewFieldType(mysql.TypeLonglong)}
 	// !((a=1||a=1)&&a=1)
@@ -322,7 +314,6 @@ func TestPushDownNot(t *testing.T) {
 }
 
 func TestFilter(t *testing.T) {
-	t.Parallel()
 	conditions := []Expression{
 		newFunction(ast.EQ, newColumn(0), newColumn(1)),
 		newFunction(ast.EQ, newColumn(1), newColumn(2)),
@@ -334,7 +325,6 @@ func TestFilter(t *testing.T) {
 }
 
 func TestFilterOutInPlace(t *testing.T) {
-	t.Parallel()
 	conditions := []Expression{
 		newFunction(ast.EQ, newColumn(0), newColumn(1)),
 		newFunction(ast.EQ, newColumn(1), newColumn(2)),
@@ -349,7 +339,6 @@ func TestFilterOutInPlace(t *testing.T) {
 }
 
 func TestHashGroupKey(t *testing.T) {
-	t.Parallel()
 	ctx := mock.NewContext()
 	sc := &stmtctx.StatementContext{TimeZone: time.Local}
 	eTypes := []types.EvalType{types.ETInt, types.ETReal, types.ETDecimal, types.ETString, types.ETTimestamp, types.ETDatetime, types.ETDuration}
@@ -392,7 +381,6 @@ func isLogicOrFunction(e Expression) bool {
 }
 
 func TestDisableParseJSONFlag4Expr(t *testing.T) {
-	t.Parallel()
 	var expr Expression
 	expr = &Column{RetType: newIntFieldType()}
 	ft := expr.GetType()
@@ -413,7 +401,6 @@ func TestDisableParseJSONFlag4Expr(t *testing.T) {
 }
 
 func TestSQLDigestTextRetriever(t *testing.T) {
-	t.Parallel()
 	// Create a fake session as the argument to the retriever, though it's actually not used when mock data is set.
 
 	r := NewSQLDigestTextRetriever()
diff --git a/infoschema/cache_test.go b/infoschema/cache_test.go
index cf86191ab4d30..977b9906c34b9 100644
--- a/infoschema/cache_test.go
+++ b/infoschema/cache_test.go
@@ -22,15 +22,11 @@ import (
 )
 
 func TestNewCache(t *testing.T) {
-	t.Parallel()
-
 	ic := infoschema.NewCache(16)
 	require.NotNil(t, ic)
 }
 
 func TestInsert(t *testing.T) {
-	t.Parallel()
-
 	ic := infoschema.NewCache(3)
 	require.NotNil(t, ic)
 
@@ -101,8 +97,6 @@ func TestInsert(t *testing.T) {
 }
 
 func TestGetByVersion(t *testing.T) {
-	t.Parallel()
-
 	ic := infoschema.NewCache(2)
 	require.NotNil(t, ic)
 	is1 := infoschema.MockInfoSchemaWithSchemaVer(nil, 1)
@@ -118,8 +112,6 @@ func TestGetByVersion(t *testing.T) {
 }
 
 func TestGetLatest(t *testing.T) {
-	t.Parallel()
-
 	ic := infoschema.NewCache(16)
 	require.NotNil(t, ic)
 	require.Nil(t, ic.GetLatest())
diff --git a/infoschema/infoschema_test.go b/infoschema/infoschema_test.go
index c66fc5e69241c..f3adc34ed7a15 100644
--- a/infoschema/infoschema_test.go
+++ b/infoschema/infoschema_test.go
@@ -38,8 +38,6 @@ import (
 )
 
 func TestBasic(t *testing.T) {
-	t.Parallel()
-
 	store, err := mockstore.NewMockStore()
 	require.NoError(t, err)
 	defer func() {
@@ -212,8 +210,6 @@ func TestBasic(t *testing.T) {
 }
 
 func TestMockInfoSchema(t *testing.T) {
-	t.Parallel()
-
 	tblID := int64(1234)
 	tblName := model.NewCIStr("tbl_m")
 	tableInfo := &model.TableInfo{
@@ -250,8 +246,6 @@ func checkApplyCreateNonExistsTableDoesNotPanic(t *testing.T, txn kv.Transaction
 
 // TestInfoTables makes sure that all tables of information_schema could be found in infoschema handle.
 func TestInfoTables(t *testing.T) {
-	t.Parallel()
-
 	store, err := mockstore.NewMockStore()
 	require.NoError(t, err)
 	defer func() {
@@ -317,8 +311,6 @@ func genGlobalID(store kv.Storage) (int64, error) {
 }
 
 func TestGetBundle(t *testing.T) {
-	t.Parallel()
-
 	store, err := mockstore.NewMockStore()
 	require.NoError(t, err)
 	defer func() {
@@ -394,8 +386,6 @@ func TestGetBundle(t *testing.T) {
 }
 
 func TestLocalTemporaryTables(t *testing.T) {
-	t.Parallel()
-
 	store, err := mockstore.NewMockStore()
 	require.NoError(t, err)
 	defer func() {
diff --git a/infoschema/metrics_schema_test.go b/infoschema/metrics_schema_test.go
index 2e12a7894651f..0cb1554f2e3ca 100644
--- a/infoschema/metrics_schema_test.go
+++ b/infoschema/metrics_schema_test.go
@@ -24,8 +24,6 @@ import (
 )
 
 func TestMetricSchemaDef(t *testing.T) {
-	t.Parallel()
-
 	for name, def := range infoschema.MetricTableMap {
 		if strings.Contains(def.PromQL, "$QUANTILE") || strings.Contains(def.PromQL, "histogram_quantile") {
 			require.Greaterf(t, def.Quantile, float64(0), "the quantile of metric table %v should > 0", name)
diff --git a/infoschema/perfschema/tables_test.go b/infoschema/perfschema/tables_test.go
index f5e910635d5fa..be739a5b6af48 100644
--- a/infoschema/perfschema/tables_test.go
+++ b/infoschema/perfschema/tables_test.go
@@ -28,14 +28,11 @@ import (
 )
 
 func TestPredefinedTables(t *testing.T) {
-	t.Parallel()
 	require.True(t, perfschema.IsPredefinedTable("EVENTS_statements_summary_by_digest"))
 	require.False(t, perfschema.IsPredefinedTable("statements"))
 }
 
 func TestPerfSchemaTables(t *testing.T) {
-	t.Parallel()
-
 	store, clean := newMockStore(t)
 	defer clean()
 	tk := testkit.NewTestKit(t, store)
diff --git a/kv/checker_test.go b/kv/checker_test.go
index 3143bd36ecfcd..0562d1f5868ad 100644
--- a/kv/checker_test.go
+++ b/kv/checker_test.go
@@ -22,8 +22,6 @@ import (
 )
 
 func TestIsRequestTypeSupported(t *testing.T) {
-	t.Parallel()
-
 	checker := kv.RequestTypeSupportedChecker{}.IsRequestTypeSupported
 	assert.True(t, checker(kv.ReqTypeSelect, kv.ReqSubTypeGroupBy))
 	assert.True(t, checker(kv.ReqTypeDAG, kv.ReqSubTypeSignature))
diff --git a/kv/error_test.go b/kv/error_test.go
index 09738aeab83da..e9842e63749df 100644
--- a/kv/error_test.go
+++ b/kv/error_test.go
@@ -23,8 +23,6 @@ import (
 )
 
 func TestError(t *testing.T) {
-	t.Parallel()
-
 	kvErrs := []*terror.Error{
 		ErrNotExist,
 		ErrTxnRetryable,
diff --git a/kv/fault_injection_test.go b/kv/fault_injection_test.go
index 754716d4bcdfb..c8743284c9a8c 100644
--- a/kv/fault_injection_test.go
+++ b/kv/fault_injection_test.go
@@ -26,8 +26,6 @@ import (
 )
 
 func TestFaultInjectionBasic(t *testing.T) {
-	t.Parallel()
-
 	var cfg InjectionConfig
 	err1 := errors.New("foo")
 	cfg.SetGetError(err1)
diff --git a/kv/key_test.go b/kv/key_test.go
index af4b6b58f1725..96b4fd2d8dfb4 100644
--- a/kv/key_test.go
+++ b/kv/key_test.go
@@ -30,8 +30,6 @@ import (
 )
 
 func TestPartialNext(t *testing.T) {
-	t.Parallel()
-
 	sc := &stmtctx.StatementContext{TimeZone: time.Local}
 	// keyA represents a multi column index.
 	keyA, err := codec.EncodeValue(sc, nil, types.NewDatum("abc"), types.NewDatum("def"))
@@ -57,8 +55,6 @@ func TestPartialNext(t *testing.T) {
 }
 
 func TestIsPoint(t *testing.T) {
-	t.Parallel()
-
 	tests := []struct {
 		start   []byte
 		end     []byte
@@ -111,16 +107,12 @@ func TestIsPoint(t *testing.T) {
 }
 
 func TestBasicFunc(t *testing.T) {
-	t.Parallel()
-
 	assert.False(t, IsTxnRetryableError(nil))
 	assert.True(t, IsTxnRetryableError(ErrTxnRetryable))
 	assert.False(t, IsTxnRetryableError(errors.New("test")))
 }
 
 func TestHandle(t *testing.T) {
-	t.Parallel()
-
 	ih := IntHandle(100)
 	assert.True(t, ih.IsInt())
 
@@ -153,8 +145,6 @@ func TestHandle(t *testing.T) {
 }
 
 func TestPaddingHandle(t *testing.T) {
-	t.Parallel()
-
 	dec := types.NewDecFromInt(1)
 	encoded, err := codec.EncodeKey(new(stmtctx.StatementContext), nil, types.NewDecimalDatum(dec))
 	assert.Nil(t, err)
@@ -171,8 +161,6 @@ func TestPaddingHandle(t *testing.T) {
 }
 
 func TestHandleMap(t *testing.T) {
-	t.Parallel()
-
 	m := NewHandleMap()
 	h := IntHandle(1)
 
diff --git a/kv/mock_test.go b/kv/mock_test.go
index e3e7d7e095edf..13740b0612eef 100644
--- a/kv/mock_test.go
+++ b/kv/mock_test.go
@@ -22,8 +22,6 @@ import (
 )
 
 func TestInterface(t *testing.T) {
-	t.Parallel()
-
 	storage := newMockStorage()
 	storage.GetClient()
 	storage.UUID()
diff --git a/kv/txn_test.go b/kv/txn_test.go
index b57dfab4dff74..84f5430c2e6d0 100644
--- a/kv/txn_test.go
+++ b/kv/txn_test.go
@@ -35,8 +35,6 @@ func mustBackOff(t *testing.T, cnt uint, sleep int) {
 }
 
 func TestRetryExceedCountError(t *testing.T) {
-	t.Parallel()
-
 	defer func(cnt uint) {
 		maxRetryCnt = cnt
 	}(maxRetryCnt)
diff --git a/kv/utils_test.go b/kv/utils_test.go
index bd7689026c18a..a91bbfc95b234 100644
--- a/kv/utils_test.go
+++ b/kv/utils_test.go
@@ -24,8 +24,6 @@ import (
 )
 
 func TestIncInt64(t *testing.T) {
-	t.Parallel()
-
 	mb := newMockMap()
 	key := Key("key")
 	v, err := IncInt64(mb, key, 1)
@@ -53,8 +51,6 @@ func TestIncInt64(t *testing.T) {
 }
 
 func TestGetInt64(t *testing.T) {
-	t.Parallel()
-
 	mb := newMockMap()
 	key := Key("key")
 	v, err := GetInt64(context.TODO(), mb, key)
diff --git a/kv/version_test.go b/kv/version_test.go
index ebea2f4aa8422..1a2aa30143d10 100644
--- a/kv/version_test.go
+++ b/kv/version_test.go
@@ -21,8 +21,6 @@ import (
 )
 
 func TestVersion(t *testing.T) {
-	t.Parallel()
-
 	le := NewVersion(42).Cmp(NewVersion(43))
 	gt := NewVersion(42).Cmp(NewVersion(41))
 	eq := NewVersion(42).Cmp(NewVersion(42))
diff --git a/meta/autoid/autoid_test.go b/meta/autoid/autoid_test.go
index c626bae2ffac6..16cfc7c64ac1c 100644
--- a/meta/autoid/autoid_test.go
+++ b/meta/autoid/autoid_test.go
@@ -529,7 +529,6 @@ func TestRollbackAlloc(t *testing.T) {
 
 // TestNextStep tests generate next auto id step.
 func TestNextStep(t *testing.T) {
-	t.Parallel()
 	nextStep := autoid.NextStep(2000000, 1*time.Nanosecond)
 	require.Equal(t, int64(2000000), nextStep)
 	nextStep = autoid.NextStep(678910, 10*time.Second)
diff --git a/meta/meta_test.go b/meta/meta_test.go
index 3bcc2dfc4bb75..29441e3e39c52 100644
--- a/meta/meta_test.go
+++ b/meta/meta_test.go
@@ -33,8 +33,6 @@ import (
 )
 
 func TestPlacementPolicy(t *testing.T) {
-	t.Parallel()
-
 	store, err := mockstore.NewMockStore()
 	require.NoError(t, err)
 
@@ -105,8 +103,6 @@ func TestPlacementPolicy(t *testing.T) {
 }
 
 func TestBackupAndRestoreAutoIDs(t *testing.T) {
-	t.Parallel()
-
 	store, err := mockstore.NewMockStore()
 	require.NoError(t, err)
 	defer func() {
@@ -154,8 +150,6 @@ func TestBackupAndRestoreAutoIDs(t *testing.T) {
 }
 
 func TestMeta(t *testing.T) {
-	t.Parallel()
-
 	store, err := mockstore.NewMockStore()
 	require.NoError(t, err)
 
@@ -389,7 +383,6 @@ func TestMeta(t *testing.T) {
 }
 
 func TestSnapshot(t *testing.T) {
-	t.Parallel()
 	store, err := mockstore.NewMockStore()
 	require.NoError(t, err)
 	defer func() {
@@ -427,7 +420,6 @@ func TestSnapshot(t *testing.T) {
 }
 
 func TestElement(t *testing.T) {
-	t.Parallel()
 	checkElement := func(key []byte, resErr error) {
 		e := &meta.Element{ID: 123, TypeKey: key}
 		eBytes := e.EncodeElement()
@@ -453,8 +445,6 @@ func TestElement(t *testing.T) {
 }
 
 func TestDDL(t *testing.T) {
-	t.Parallel()
-
 	testCases := []struct {
 		desc        string
 		startHandle kv.Handle
@@ -476,7 +466,6 @@ func TestDDL(t *testing.T) {
 		// copy iterator variable into a new variable, see issue #27779
 		tc := tc
 		t.Run(tc.desc, func(t *testing.T) {
-			t.Parallel()
 			store, err := mockstore.NewMockStore()
 			require.NoError(t, err)
 			defer func() {
@@ -619,8 +608,6 @@ func TestDDL(t *testing.T) {
 }
 
 func TestAddIndexJob(t *testing.T) {
-	t.Parallel()
-
 	store, err := mockstore.NewMockStore()
 	require.NoError(t, err)
 	defer func() {
diff --git a/metrics/grafana/tidb.json b/metrics/grafana/tidb.json
index 2776e7625570f..518112d04abcc 100644
--- a/metrics/grafana/tidb.json
+++ b/metrics/grafana/tidb.json
@@ -5426,7 +5426,7 @@
           "steppedLine": false,
           "targets": [
             {
-              "expr": "sum(tidb_tikvclient_safets_gap_seconds{tidb_cluster=\"$tidb_cluster\", instance=~\"$instance\"}) by (instance, store)",
+              "expr": "tidb_tikvclient_min_safets_gap_seconds{tidb_cluster=\"$tidb_cluster\"}",
               "format": "time_series",
               "intervalFactor": 2,
               "legendFormat": "{{instance}}-store-{{store}}",
@@ -5438,7 +5438,7 @@
           "timeFrom": null,
           "timeRegions": [],
           "timeShift": null,
-          "title": "Max SafeTS gap",
+          "title": "Max SafeTS Gap",
           "tooltip": {
             "msResolution": false,
             "shared": true,
diff --git a/parser/ast/ddl_test.go b/parser/ast/ddl_test.go
index cb0e9c9f25dc8..af4ecc5a6ca85 100644
--- a/parser/ast/ddl_test.go
+++ b/parser/ast/ddl_test.go
@@ -23,7 +23,6 @@ import (
 )
 
 func TestDDLVisitorCover(t *testing.T) {
-	t.Parallel()
 	ce := &checkExpr{}
 	constraint := &Constraint{Keys: []*IndexPartSpecification{{Column: &ColumnName{}}, {Column: &ColumnName{}}}, Refer: &ReferenceDef{}, Option: &IndexOption{}}
 
@@ -68,7 +67,6 @@ func TestDDLVisitorCover(t *testing.T) {
 }
 
 func TestDDLIndexColNameRestore(t *testing.T) {
-	t.Parallel()
 	testCases := []NodeRestoreTestCase{
 		{"(a + 1)", "(`a`+1)"},
 		{"(1 * 1 + (1 + 1))", "(1*1+(1+1))"},
@@ -81,7 +79,6 @@ func TestDDLIndexColNameRestore(t *testing.T) {
 }
 
 func TestDDLIndexExprRestore(t *testing.T) {
-	t.Parallel()
 	testCases := []NodeRestoreTestCase{
 		{"world", "`world`"},
 		{"world(2)", "`world`(2)"},
@@ -93,7 +90,6 @@ func TestDDLIndexExprRestore(t *testing.T) {
 }
 
 func TestDDLOnDeleteRestore(t *testing.T) {
-	t.Parallel()
 	testCases := []NodeRestoreTestCase{
 		{"on delete restrict", "ON DELETE RESTRICT"},
 		{"on delete CASCADE", "ON DELETE CASCADE"},
@@ -109,7 +105,6 @@ func TestDDLOnDeleteRestore(t *testing.T) {
 }
 
 func TestDDLOnUpdateRestore(t *testing.T) {
-	t.Parallel()
 	testCases := []NodeRestoreTestCase{
 		{"ON UPDATE RESTRICT", "ON UPDATE RESTRICT"},
 		{"on update CASCADE", "ON UPDATE CASCADE"},
@@ -125,7 +120,6 @@ func TestDDLOnUpdateRestore(t *testing.T) {
 }
 
 func TestDDLIndexOption(t *testing.T) {
-	t.Parallel()
 	testCases := []NodeRestoreTestCase{
 		{"key_block_size=16", "KEY_BLOCK_SIZE=16"},
 		{"USING HASH", "USING HASH"},
@@ -144,7 +138,6 @@ func TestDDLIndexOption(t *testing.T) {
 }
 
 func TestTableToTableRestore(t *testing.T) {
-	t.Parallel()
 	testCases := []NodeRestoreTestCase{
 		{"t1 to t2", "`t1` TO `t2`"},
 	}
@@ -155,7 +148,6 @@ func TestTableToTableRestore(t *testing.T) {
 }
 
 func TestDDLReferenceDefRestore(t *testing.T) {
-	t.Parallel()
 	testCases := []NodeRestoreTestCase{
 		{"REFERENCES parent(id) ON DELETE CASCADE ON UPDATE RESTRICT", "REFERENCES `parent`(`id`) ON DELETE CASCADE ON UPDATE RESTRICT"},
 		{"REFERENCES parent(id) ON DELETE CASCADE", "REFERENCES `parent`(`id`) ON DELETE CASCADE"},
@@ -172,7 +164,6 @@ func TestDDLReferenceDefRestore(t *testing.T) {
 }
 
 func TestDDLConstraintRestore(t *testing.T) {
-	t.Parallel()
 	testCases := []NodeRestoreTestCase{
 		{"INDEX par_ind (parent_id)", "INDEX `par_ind`(`parent_id`)"},
 		{"INDEX par_ind (parent_id(6))", "INDEX `par_ind`(`parent_id`(6))"},
@@ -225,7 +216,6 @@ func TestDDLConstraintRestore(t *testing.T) {
 }
 
 func TestDDLColumnOptionRestore(t *testing.T) {
-	t.Parallel()
 	testCases := []NodeRestoreTestCase{
 		{"primary key", "PRIMARY KEY"},
 		{"not null", "NOT NULL"},
@@ -260,7 +250,6 @@ func TestDDLColumnOptionRestore(t *testing.T) {
 }
 
 func TestDDLColumnDefRestore(t *testing.T) {
-	t.Parallel()
 	testCases := []NodeRestoreTestCase{
 		// for type
 		{"id json", "`id` JSON"},
@@ -385,7 +374,6 @@ func TestDDLColumnDefRestore(t *testing.T) {
 }
 
 func TestDDLTruncateTableStmtRestore(t *testing.T) {
-	t.Parallel()
 	testCases := []NodeRestoreTestCase{
 		{"truncate t1", "TRUNCATE TABLE `t1`"},
 		{"truncate table t1", "TRUNCATE TABLE `t1`"},
@@ -398,7 +386,6 @@ func TestDDLTruncateTableStmtRestore(t *testing.T) {
 }
 
 func TestDDLDropTableStmtRestore(t *testing.T) {
-	t.Parallel()
 	testCases := []NodeRestoreTestCase{
 		{"drop table t1", "DROP TABLE `t1`"},
 		{"drop table if exists t1", "DROP TABLE IF EXISTS `t1`"},
@@ -413,7 +400,6 @@ func TestDDLDropTableStmtRestore(t *testing.T) {
 }
 
 func TestColumnPositionRestore(t *testing.T) {
-	t.Parallel()
 	testCases := []NodeRestoreTestCase{
 		{"", ""},
 		{"first", "FIRST"},
@@ -426,7 +412,6 @@ func TestColumnPositionRestore(t *testing.T) {
 }
 
 func TestAlterTableSpecRestore(t *testing.T) {
-	t.Parallel()
 	testCases := []NodeRestoreTestCase{
 		{"ENGINE innodb", "ENGINE = innodb"},
 		{"ENGINE = innodb", "ENGINE = innodb"},
@@ -556,7 +541,6 @@ func TestAlterTableSpecRestore(t *testing.T) {
 }
 
 func TestAlterTableOptionRestore(t *testing.T) {
-	t.Parallel()
 	testCases := []NodeRestoreTestCase{
 		{"ALTER TABLE t ROW_FORMAT = COMPRESSED KEY_BLOCK_SIZE = 8", "ALTER TABLE `t` ROW_FORMAT = COMPRESSED KEY_BLOCK_SIZE = 8"},
 		{"ALTER TABLE t ROW_FORMAT = COMPRESSED, KEY_BLOCK_SIZE = 8", "ALTER TABLE `t` ROW_FORMAT = COMPRESSED, KEY_BLOCK_SIZE = 8"},
@@ -568,7 +552,6 @@ func TestAlterTableOptionRestore(t *testing.T) {
 }
 
 func TestAdminRepairTableRestore(t *testing.T) {
-	t.Parallel()
 	testCases := []NodeRestoreTestCase{
 		{"ADMIN REPAIR TABLE t CREATE TABLE t (a int)", "ADMIN REPAIR TABLE `t` CREATE TABLE `t` (`a` INT)"},
 		{"ADMIN REPAIR TABLE t CREATE TABLE t (a char(1), b int)", "ADMIN REPAIR TABLE `t` CREATE TABLE `t` (`a` CHAR(1),`b` INT)"},
@@ -581,7 +564,6 @@ func TestAdminRepairTableRestore(t *testing.T) {
 }
 
 func TestSequenceRestore(t *testing.T) {
-	t.Parallel()
 	testCases := []NodeRestoreTestCase{
 		{"create sequence seq", "CREATE SEQUENCE `seq`"},
 		{"create sequence if not exists seq", "CREATE SEQUENCE IF NOT EXISTS `seq`"},
@@ -626,7 +608,6 @@ func TestSequenceRestore(t *testing.T) {
 }
 
 func TestDropIndexRestore(t *testing.T) {
-	t.Parallel()
 	sourceSQL := "drop index if exists idx on t"
 	cases := []struct {
 		flags     format.RestoreFlags
diff --git a/parser/ast/dml_test.go b/parser/ast/dml_test.go
index e98e6bd2a69ea..624717d2d7c54 100644
--- a/parser/ast/dml_test.go
+++ b/parser/ast/dml_test.go
@@ -21,7 +21,6 @@ import (
 )
 
 func TestDMLVisitorCover(t *testing.T) {
-	t.Parallel()
 	ce := &checkExpr{}
 
 	tableRefsClause := &TableRefsClause{TableRefs: &Join{Left: &TableSource{Source: &TableName{}}, On: &OnCondition{Expr: ce}}}
@@ -72,7 +71,6 @@ func TestDMLVisitorCover(t *testing.T) {
 }
 
 func TestTableNameRestore(t *testing.T) {
-	t.Parallel()
 	testCases := []NodeRestoreTestCase{
 		{"dbb.`tbb1`", "`dbb`.`tbb1`"},
 		{"`tbb2`", "`tbb2`"},
@@ -88,7 +86,6 @@ func TestTableNameRestore(t *testing.T) {
 }
 
 func TestTableNameIndexHintsRestore(t *testing.T) {
-	t.Parallel()
 	testCases := []NodeRestoreTestCase{
 		{"t use index (hello)", "`t` USE INDEX (`hello`)"},
 		{"t use index (hello, world)", "`t` USE INDEX (`hello`, `world`)"},
@@ -131,7 +128,6 @@ func TestTableNameIndexHintsRestore(t *testing.T) {
 }
 
 func TestLimitRestore(t *testing.T) {
-	t.Parallel()
 	testCases := []NodeRestoreTestCase{
 		{"limit 10", "LIMIT 10"},
 		{"limit 10,20", "LIMIT 10,20"},
@@ -144,7 +140,6 @@ func TestLimitRestore(t *testing.T) {
 }
 
 func TestWildCardFieldRestore(t *testing.T) {
-	t.Parallel()
 	testCases := []NodeRestoreTestCase{
 		{"*", "*"},
 		{"t.*", "`t`.*"},
@@ -157,7 +152,6 @@ func TestWildCardFieldRestore(t *testing.T) {
 }
 
 func TestSelectFieldRestore(t *testing.T) {
-	t.Parallel()
 	testCases := []NodeRestoreTestCase{
 		{"*", "*"},
 		{"t.*", "`t`.*"},
@@ -172,7 +166,6 @@ func TestSelectFieldRestore(t *testing.T) {
 }
 
 func TestFieldListRestore(t *testing.T) {
-	t.Parallel()
 	testCases := []NodeRestoreTestCase{
 		{"*", "*"},
 		{"t.*", "`t`.*"},
@@ -187,7 +180,6 @@ func TestFieldListRestore(t *testing.T) {
 }
 
 func TestTableSourceRestore(t *testing.T) {
-	t.Parallel()
 	testCases := []NodeRestoreTestCase{
 		{"tbl", "`tbl`"},
 		{"tbl as t", "`tbl` AS `t`"},
@@ -201,7 +193,6 @@ func TestTableSourceRestore(t *testing.T) {
 }
 
 func TestOnConditionRestore(t *testing.T) {
-	t.Parallel()
 	testCases := []NodeRestoreTestCase{
 		{"on t1.a=t2.a", "ON `t1`.`a`=`t2`.`a`"},
 		{"on t1.a=t2.a and t1.b=t2.b", "ON `t1`.`a`=`t2`.`a` AND `t1`.`b`=`t2`.`b`"},
@@ -213,7 +204,6 @@ func TestOnConditionRestore(t *testing.T) {
 }
 
 func TestJoinRestore(t *testing.T) {
-	t.Parallel()
 	testCases := []NodeRestoreTestCase{
 		{"t1 natural join t2", "`t1` NATURAL JOIN `t2`"},
 		{"t1 natural left join t2", "`t1` NATURAL LEFT JOIN `t2`"},
@@ -252,7 +242,6 @@ func TestJoinRestore(t *testing.T) {
 }
 
 func TestTableRefsClauseRestore(t *testing.T) {
-	t.Parallel()
 	testCases := []NodeRestoreTestCase{
 		{"t", "`t`"},
 		{"t1 join t2", "`t1` JOIN `t2`"},
@@ -265,7 +254,6 @@ func TestTableRefsClauseRestore(t *testing.T) {
 }
 
 func TestDeleteTableListRestore(t *testing.T) {
-	t.Parallel()
 	testCases := []NodeRestoreTestCase{
 		{"t1,t2", "`t1`,`t2`"},
 	}
@@ -277,7 +265,6 @@ func TestDeleteTableListRestore(t *testing.T) {
 }
 
 func TestDeleteTableIndexHintRestore(t *testing.T) {
-	t.Parallel()
 	testCases := []NodeRestoreTestCase{
 		{"DELETE FROM t1 USE key (`fld1`) WHERE fld=1",
 			"DELETE FROM `t1` USE INDEX (`fld1`) WHERE `fld`=1"},
@@ -292,7 +279,6 @@ func TestDeleteTableIndexHintRestore(t *testing.T) {
 }
 
 func TestByItemRestore(t *testing.T) {
-	t.Parallel()
 	testCases := []NodeRestoreTestCase{
 		{"a", "`a`"},
 		{"a desc", "`a` DESC"},
@@ -305,7 +291,6 @@ func TestByItemRestore(t *testing.T) {
 }
 
 func TestGroupByClauseRestore(t *testing.T) {
-	t.Parallel()
 	testCases := []NodeRestoreTestCase{
 		{"GROUP BY a,b desc", "GROUP BY `a`,`b` DESC"},
 		{"GROUP BY 1 desc,b", "GROUP BY 1 DESC,`b`"},
@@ -317,7 +302,6 @@ func TestGroupByClauseRestore(t *testing.T) {
 }
 
 func TestOrderByClauseRestore(t *testing.T) {
-	t.Parallel()
 	testCases := []NodeRestoreTestCase{
 		{"ORDER BY a", "ORDER BY `a`"},
 		{"ORDER BY a,b", "ORDER BY `a`,`b`"},
@@ -334,7 +318,6 @@ func TestOrderByClauseRestore(t *testing.T) {
 }
 
 func TestAssignmentRestore(t *testing.T) {
-	t.Parallel()
 	testCases := []NodeRestoreTestCase{
 		{"a=1", "`a`=1"},
 		{"b=1+2", "`b`=1+2"},
@@ -346,7 +329,6 @@ func TestAssignmentRestore(t *testing.T) {
 }
 
 func TestHavingClauseRestore(t *testing.T) {
-	t.Parallel()
 	testCases := []NodeRestoreTestCase{
 		{"HAVING a", "HAVING `a`"},
 		{"HAVING NULL", "HAVING NULL"},
@@ -359,7 +341,6 @@ func TestHavingClauseRestore(t *testing.T) {
 }
 
 func TestFrameBoundRestore(t *testing.T) {
-	t.Parallel()
 	testCases := []NodeRestoreTestCase{
 		{"CURRENT ROW", "CURRENT ROW"},
 		{"UNBOUNDED PRECEDING", "UNBOUNDED PRECEDING"},
@@ -378,7 +359,6 @@ func TestFrameBoundRestore(t *testing.T) {
 }
 
 func TestFrameClauseRestore(t *testing.T) {
-	t.Parallel()
 	testCases := []NodeRestoreTestCase{
 		{"ROWS CURRENT ROW", "ROWS BETWEEN CURRENT ROW AND CURRENT ROW"},
 		{"ROWS UNBOUNDED PRECEDING", "ROWS BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW"},
@@ -393,7 +373,6 @@ func TestFrameClauseRestore(t *testing.T) {
 }
 
 func TestPartitionByClauseRestore(t *testing.T) {
-	t.Parallel()
 	testCases := []NodeRestoreTestCase{
 		{"PARTITION BY a", "PARTITION BY `a`"},
 		{"PARTITION BY NULL", "PARTITION BY NULL"},
@@ -406,7 +385,6 @@ func TestPartitionByClauseRestore(t *testing.T) {
 }
 
 func TestWindowSpecRestore(t *testing.T) {
-	t.Parallel()
 	testCases := []NodeRestoreTestCase{
 		{"w as ()", "`w` AS ()"},
 		{"w as (w1)", "`w` AS (`w1`)"},
@@ -432,7 +410,6 @@ func TestWindowSpecRestore(t *testing.T) {
 }
 
 func TestFulltextSearchModifier(t *testing.T) {
-	t.Parallel()
 	require.False(t, FulltextSearchModifier(FulltextSearchModifierNaturalLanguageMode).IsBooleanMode())
 	require.True(t, FulltextSearchModifier(FulltextSearchModifierNaturalLanguageMode).IsNaturalLanguageMode())
 	require.False(t, FulltextSearchModifier(FulltextSearchModifierNaturalLanguageMode).WithQueryExpansion())
diff --git a/parser/ast/expressions_test.go b/parser/ast/expressions_test.go
index c4b14d44646db..7f01c84c1049f 100644
--- a/parser/ast/expressions_test.go
+++ b/parser/ast/expressions_test.go
@@ -61,7 +61,6 @@ func (n *checkExpr) reset() {
 }
 
 func TestExpresionsVisitorCover(t *testing.T) {
-	t.Parallel()
 	ce := &checkExpr{}
 	stmts :=
 		[]struct {
@@ -102,7 +101,6 @@ func TestExpresionsVisitorCover(t *testing.T) {
 }
 
 func TestUnaryOperationExprRestore(t *testing.T) {
-	t.Parallel()
 	testCases := []NodeRestoreTestCase{
 		{"++1", "++1"},
 		{"--1", "--1"},
@@ -119,7 +117,6 @@ func TestUnaryOperationExprRestore(t *testing.T) {
 }
 
 func TestColumnNameExprRestore(t *testing.T) {
-	t.Parallel()
 	testCases := []NodeRestoreTestCase{
 		{"abc", "`abc`"},
 		{"`abc`", "`abc`"},
@@ -136,7 +133,6 @@ func TestColumnNameExprRestore(t *testing.T) {
 }
 
 func TestIsNullExprRestore(t *testing.T) {
-	t.Parallel()
 	testCases := []NodeRestoreTestCase{
 		{"a is null", "`a` IS NULL"},
 		{"a is not null", "`a` IS NOT NULL"},
@@ -148,7 +144,6 @@ func TestIsNullExprRestore(t *testing.T) {
 }
 
 func TestIsTruthRestore(t *testing.T) {
-	t.Parallel()
 	testCases := []NodeRestoreTestCase{
 		{"a is true", "`a` IS TRUE"},
 		{"a is not true", "`a` IS NOT TRUE"},
@@ -162,7 +157,6 @@ func TestIsTruthRestore(t *testing.T) {
 }
 
 func TestBetweenExprRestore(t *testing.T) {
-	t.Parallel()
 	testCases := []NodeRestoreTestCase{
 		{"b between 1 and 2", "`b` BETWEEN 1 AND 2"},
 		{"b not between 1 and 2", "`b` NOT BETWEEN 1 AND 2"},
@@ -177,7 +171,6 @@ func TestBetweenExprRestore(t *testing.T) {
 }
 
 func TestCaseExpr(t *testing.T) {
-	t.Parallel()
 	testCases := []NodeRestoreTestCase{
 		{"case when 1 then 2 end", "CASE WHEN 1 THEN 2 END"},
 		{"case when 1 then 'a' when 2 then 'b' end", "CASE WHEN 1 THEN _UTF8MB4'a' WHEN 2 THEN _UTF8MB4'b' END"},
@@ -192,7 +185,6 @@ func TestCaseExpr(t *testing.T) {
 }
 
 func TestBinaryOperationExpr(t *testing.T) {
-	t.Parallel()
 	testCases := []NodeRestoreTestCase{
 		{"'a'!=1", "_UTF8MB4'a'!=1"},
 		{"a!=1", "`a`!=1"},
@@ -220,7 +212,6 @@ func TestBinaryOperationExpr(t *testing.T) {
 }
 
 func TestBinaryOperationExprWithFlags(t *testing.T) {
-	t.Parallel()
 	testCases := []NodeRestoreTestCase{
 		{"'a'!=1", "_UTF8MB4'a' != 1"},
 		{"a!=1", "`a` != 1"},
@@ -239,7 +230,6 @@ func TestBinaryOperationExprWithFlags(t *testing.T) {
 }
 
 func TestParenthesesExpr(t *testing.T) {
-	t.Parallel()
 	testCases := []NodeRestoreTestCase{
 		{"(1+2)*3", "(1+2)*3"},
 		{"1+2*3", "1+2*3"},
@@ -251,7 +241,6 @@ func TestParenthesesExpr(t *testing.T) {
 }
 
 func TestWhenClause(t *testing.T) {
-	t.Parallel()
 	testCases := []NodeRestoreTestCase{
 		{"when 1 then 2", "WHEN 1 THEN 2"},
 		{"when 1 then 'a'", "WHEN 1 THEN _UTF8MB4'a'"},
@@ -264,7 +253,6 @@ func TestWhenClause(t *testing.T) {
 }
 
 func TestDefaultExpr(t *testing.T) {
-	t.Parallel()
 	testCases := []NodeRestoreTestCase{
 		{"default", "DEFAULT"},
 		{"default(i)", "DEFAULT(`i`)"},
@@ -276,7 +264,6 @@ func TestDefaultExpr(t *testing.T) {
 }
 
 func TestPatternInExprRestore(t *testing.T) {
-	t.Parallel()
 	testCases := []NodeRestoreTestCase{
 		{"'a' in ('b')", "_UTF8MB4'a' IN (_UTF8MB4'b')"},
 		{"2 in (0,3,7)", "2 IN (0,3,7)"},
@@ -291,7 +278,6 @@ func TestPatternInExprRestore(t *testing.T) {
 }
 
 func TestPatternLikeExprRestore(t *testing.T) {
-	t.Parallel()
 	testCases := []NodeRestoreTestCase{
 		{"a like 't1'", "`a` LIKE _UTF8MB4't1'"},
 		{"a like 't1%'", "`a` LIKE _UTF8MB4't1%'"},
@@ -309,7 +295,6 @@ func TestPatternLikeExprRestore(t *testing.T) {
 }
 
 func TestValuesExpr(t *testing.T) {
-	t.Parallel()
 	testCases := []NodeRestoreTestCase{
 		{"values(a)", "VALUES(`a`)"},
 		{"values(a)+values(b)", "VALUES(`a`)+VALUES(`b`)"},
@@ -321,7 +306,6 @@ func TestValuesExpr(t *testing.T) {
 }
 
 func TestPatternRegexpExprRestore(t *testing.T) {
-	t.Parallel()
 	testCases := []NodeRestoreTestCase{
 		{"a regexp 't1'", "`a` REGEXP _UTF8MB4't1'"},
 		{"a regexp '^[abc][0-9]{11}|ok$'", "`a` REGEXP _UTF8MB4'^[abc][0-9]{11}|ok$'"},
@@ -339,7 +323,6 @@ func TestPatternRegexpExprRestore(t *testing.T) {
 }
 
 func TestRowExprRestore(t *testing.T) {
-	t.Parallel()
 	testCases := []NodeRestoreTestCase{
 		{"(1,2)", "ROW(1,2)"},
 		{"(col1,col2)", "ROW(`col1`,`col2`)"},
@@ -353,7 +336,6 @@ func TestRowExprRestore(t *testing.T) {
 }
 
 func TestMaxValueExprRestore(t *testing.T) {
-	t.Parallel()
 	testCases := []NodeRestoreTestCase{
 		{"maxvalue", "MAXVALUE"},
 	}
@@ -364,7 +346,6 @@ func TestMaxValueExprRestore(t *testing.T) {
 }
 
 func TestPositionExprRestore(t *testing.T) {
-	t.Parallel()
 	testCases := []NodeRestoreTestCase{
 		{"1", "1"},
 	}
@@ -376,7 +357,6 @@ func TestPositionExprRestore(t *testing.T) {
 }
 
 func TestExistsSubqueryExprRestore(t *testing.T) {
-	t.Parallel()
 	testCases := []NodeRestoreTestCase{
 		{"EXISTS (SELECT 2)", "EXISTS (SELECT 2)"},
 		{"NOT EXISTS (SELECT 2)", "NOT EXISTS (SELECT 2)"},
@@ -390,7 +370,6 @@ func TestExistsSubqueryExprRestore(t *testing.T) {
 }
 
 func TestVariableExpr(t *testing.T) {
-	t.Parallel()
 	testCases := []NodeRestoreTestCase{
 		{"@a>1", "@`a`>1"},
 		{"@`aB`+1", "@`aB`+1"},
@@ -414,7 +393,6 @@ func TestVariableExpr(t *testing.T) {
 }
 
 func TestMatchAgainstExpr(t *testing.T) {
-	t.Parallel()
 	testCases := []NodeRestoreTestCase{
 		{`MATCH(content, title) AGAINST ('search for')`, "MATCH (`content`,`title`) AGAINST (_UTF8MB4'search for')"},
 		{`MATCH(content) AGAINST ('search for' IN BOOLEAN MODE)`, "MATCH (`content`) AGAINST (_UTF8MB4'search for' IN BOOLEAN MODE)"},
diff --git a/parser/ast/flag_test.go b/parser/ast/flag_test.go
index f81c5dc139aa9..e90a407f9ddcb 100644
--- a/parser/ast/flag_test.go
+++ b/parser/ast/flag_test.go
@@ -22,7 +22,6 @@ import (
 )
 
 func TestHasAggFlag(t *testing.T) {
-	t.Parallel()
 	expr := &ast.BetweenExpr{}
 	flagTests := []struct {
 		flag   uint64
@@ -39,7 +38,6 @@ func TestHasAggFlag(t *testing.T) {
 }
 
 func TestFlag(t *testing.T) {
-	t.Parallel()
 	flagTests := []struct {
 		expr string
 		flag uint64
diff --git a/parser/ast/format_test.go b/parser/ast/format_test.go
index 7f370f9a18e1d..59424d2876d34 100644
--- a/parser/ast/format_test.go
+++ b/parser/ast/format_test.go
@@ -15,7 +15,6 @@ func getDefaultCharsetAndCollate() (string, string) {
 }
 
 func TestAstFormat(t *testing.T) {
-	t.Parallel()
 	var testcases = []struct {
 		input  string
 		output string
diff --git a/parser/ast/functions_test.go b/parser/ast/functions_test.go
index a6fa019d3f064..9f38e2d70958f 100644
--- a/parser/ast/functions_test.go
+++ b/parser/ast/functions_test.go
@@ -24,7 +24,6 @@ import (
 )
 
 func TestFunctionsVisitorCover(t *testing.T) {
-	t.Parallel()
 	valueExpr := NewValueExpr(42, mysql.DefaultCharset, mysql.DefaultCollationName)
 	stmts := []Node{
 		&AggregateFuncExpr{Args: []ExprNode{valueExpr}},
@@ -40,7 +39,6 @@ func TestFunctionsVisitorCover(t *testing.T) {
 }
 
 func TestFuncCallExprRestore(t *testing.T) {
-	t.Parallel()
 	testCases := []NodeRestoreTestCase{
 		{"JSON_ARRAYAGG(attribute)", "JSON_ARRAYAGG(`attribute`)"},
 		{"JSON_OBJECTAGG(attribute, value)", "JSON_OBJECTAGG(`attribute`, `value`)"},
@@ -155,7 +153,6 @@ func TestAggregateFuncExprRestore(t *testing.T) {
 }
 
 func TestConvert(t *testing.T) {
-	t.Parallel()
 	// Test case for CONVERT(expr USING transcoding_name).
 	cases := []struct {
 		SQL          string
@@ -185,7 +182,6 @@ func TestConvert(t *testing.T) {
 }
 
 func TestChar(t *testing.T) {
-	t.Parallel()
 	// Test case for CHAR(N USING charset_name)
 	cases := []struct {
 		SQL          string
@@ -215,7 +211,6 @@ func TestChar(t *testing.T) {
 }
 
 func TestWindowFuncExprRestore(t *testing.T) {
-	t.Parallel()
 	testCases := []NodeRestoreTestCase{
 		{"RANK() OVER w", "RANK() OVER `w`"},
 		{"RANK() OVER (PARTITION BY a)", "RANK() OVER (PARTITION BY `a`)"},
@@ -235,7 +230,6 @@ func TestWindowFuncExprRestore(t *testing.T) {
 }
 
 func TestGenericFuncRestore(t *testing.T) {
-	t.Parallel()
 	testCases := []NodeRestoreTestCase{
 		{"s.a()", "`s`.`a`()"},
 		{"`s`.`a`()", "`s`.`a`()"},
diff --git a/parser/ast/misc_test.go b/parser/ast/misc_test.go
index dddcb631ffa9c..7b7df348f86fa 100644
--- a/parser/ast/misc_test.go
+++ b/parser/ast/misc_test.go
@@ -43,7 +43,6 @@ func (visitor1) Enter(in ast.Node) (ast.Node, bool) {
 }
 
 func TestMiscVisitorCover(t *testing.T) {
-	t.Parallel()
 	valueExpr := ast.NewValueExpr(42, mysql.DefaultCharset, mysql.DefaultCollationName)
 	stmts := []ast.Node{
 		&ast.AdminStmt{},
@@ -86,7 +85,6 @@ func TestMiscVisitorCover(t *testing.T) {
 }
 
 func TestDDLVisitorCoverMisc(t *testing.T) {
-	t.Parallel()
 	sql := `
 create table t (c1 smallint unsigned, c2 int unsigned);
 alter table t add column a smallint unsigned after b;
@@ -112,7 +110,6 @@ constraint foreign key (jobabbr) references ffxi_jobtype (jobabbr) on delete cas
 }
 
 func TestDMLVistorCover(t *testing.T) {
-	t.Parallel()
 	sql := `delete from somelog where user = 'jcole' order by timestamp_column limit 1;
 delete t1, t2 from t1 inner join t2 inner join t3 where t1.id=t2.id and t2.id=t3.id;
 select * from t where exists(select * from t k where t.c = k.c having sum(c) = 1);
@@ -133,7 +130,6 @@ load data infile '/tmp/t.csv' into table t fields terminated by 'ab' enclosed by
 
 // test Change Pump or drainer status sql parser
 func TestChangeStmt(t *testing.T) {
-	t.Parallel()
 	sql := `change pump to node_state='paused' for node_id '127.0.0.1:8249';
 change drainer to node_state='paused' for node_id '127.0.0.1:8249';
 shutdown;`
@@ -148,7 +144,6 @@ shutdown;`
 }
 
 func TestSensitiveStatement(t *testing.T) {
-	t.Parallel()
 	positive := []ast.StmtNode{
 		&ast.SetPwdStmt{},
 		&ast.CreateUserStmt{},
@@ -180,7 +175,6 @@ func TestSensitiveStatement(t *testing.T) {
 }
 
 func TestUserSpec(t *testing.T) {
-	t.Parallel()
 	hashString := "*3D56A309CD04FA2EEF181462E59011F075C89548"
 	u := ast.UserSpec{
 		User: &auth.UserIdentity{
@@ -212,7 +206,6 @@ func TestUserSpec(t *testing.T) {
 }
 
 func TestTableOptimizerHintRestore(t *testing.T) {
-	t.Parallel()
 	testCases := []NodeRestoreTestCase{
 		{"USE_INDEX(t1 c1)", "USE_INDEX(`t1` `c1`)"},
 		{"USE_INDEX(test.t1 c1)", "USE_INDEX(`test`.`t1` `c1`)"},
@@ -288,7 +281,6 @@ func TestTableOptimizerHintRestore(t *testing.T) {
 }
 
 func TestChangeStmtRestore(t *testing.T) {
-	t.Parallel()
 	testCases := []NodeRestoreTestCase{
 		{"CHANGE PUMP TO NODE_STATE ='paused' FOR NODE_ID '127.0.0.1:9090'", "CHANGE PUMP TO NODE_STATE ='paused' FOR NODE_ID '127.0.0.1:9090'"},
 		{"CHANGE DRAINER TO NODE_STATE ='paused' FOR NODE_ID '127.0.0.1:9090'", "CHANGE DRAINER TO NODE_STATE ='paused' FOR NODE_ID '127.0.0.1:9090'"},
@@ -300,7 +292,6 @@ func TestChangeStmtRestore(t *testing.T) {
 }
 
 func TestBRIESecureText(t *testing.T) {
-	t.Parallel()
 	testCases := []struct {
 		input   string
 		secured string
diff --git a/parser/ast/util_test.go b/parser/ast/util_test.go
index 7dfd5e10b6d90..d8cb06eee448c 100644
--- a/parser/ast/util_test.go
+++ b/parser/ast/util_test.go
@@ -26,7 +26,6 @@ import (
 )
 
 func TestCacheable(t *testing.T) {
-	t.Parallel()
 	// test non-SelectStmt
 	var stmt Node = &DeleteStmt{}
 	require.False(t, IsReadOnly(stmt))
@@ -76,7 +75,6 @@ func TestCacheable(t *testing.T) {
 }
 
 func TestUnionReadOnly(t *testing.T) {
-	t.Parallel()
 	selectReadOnly := &SelectStmt{}
 	selectForUpdate := &SelectStmt{
 		LockInfo: &SelectLockInfo{LockType: SelectLockForUpdate},
diff --git a/parser/auth/caching_sha2_test.go b/parser/auth/caching_sha2_test.go
index 5e0b64569230d..73e42ba9d28a8 100644
--- a/parser/auth/caching_sha2_test.go
+++ b/parser/auth/caching_sha2_test.go
@@ -21,7 +21,6 @@ import (
 )
 
 func TestCheckShaPasswordGood(t *testing.T) {
-	t.Parallel()
 	pwd := "foobar"
 	pwhash, _ := hex.DecodeString("24412430303524031A69251C34295C4B35167C7F1E5A7B63091349503974624D34504B5A424679354856336868686F52485A736E4A733368786E427575516C73446469496537")
 	r, err := CheckShaPassword(pwhash, pwd)
@@ -30,7 +29,6 @@ func TestCheckShaPasswordGood(t *testing.T) {
 }
 
 func TestCheckShaPasswordBad(t *testing.T) {
-	t.Parallel()
 	pwd := "not_foobar"
 	pwhash, _ := hex.DecodeString("24412430303524031A69251C34295C4B35167C7F1E5A7B63091349503974624D34504B5A424679354856336868686F52485A736E4A733368786E427575516C73446469496537")
 	r, err := CheckShaPassword(pwhash, pwd)
@@ -39,7 +37,6 @@ func TestCheckShaPasswordBad(t *testing.T) {
 }
 
 func TestCheckShaPasswordShort(t *testing.T) {
-	t.Parallel()
 	pwd := "not_foobar"
 	pwhash, _ := hex.DecodeString("aaaaaaaa")
 	_, err := CheckShaPassword(pwhash, pwd)
@@ -47,7 +44,6 @@ func TestCheckShaPasswordShort(t *testing.T) {
 }
 
 func TestCheckShaPasswordDigetTypeIncompatible(t *testing.T) {
-	t.Parallel()
 	pwd := "not_foobar"
 	pwhash, _ := hex.DecodeString("24422430303524031A69251C34295C4B35167C7F1E5A7B63091349503974624D34504B5A424679354856336868686F52485A736E4A733368786E427575516C73446469496537")
 	_, err := CheckShaPassword(pwhash, pwd)
@@ -55,7 +51,6 @@ func TestCheckShaPasswordDigetTypeIncompatible(t *testing.T) {
 }
 
 func TestCheckShaPasswordIterationsInvalid(t *testing.T) {
-	t.Parallel()
 	pwd := "not_foobar"
 	pwhash, _ := hex.DecodeString("24412430304124031A69251C34295C4B35167C7F1E5A7B63091349503974624D34504B5A424679354856336868686F52485A736E4A733368786E427575516C73446469496537")
 	_, err := CheckShaPassword(pwhash, pwd)
@@ -65,7 +60,6 @@ func TestCheckShaPasswordIterationsInvalid(t *testing.T) {
 // The output from NewSha2Password is not stable as the hash is based on the genrated salt.
 // This is why CheckShaPassword is used here.
 func TestNewSha2Password(t *testing.T) {
-	t.Parallel()
 	pwd := "testpwd"
 	pwhash := NewSha2Password(pwd)
 	r, err := CheckShaPassword([]byte(pwhash), pwd)
diff --git a/parser/auth/mysql_native_password_test.go b/parser/auth/mysql_native_password_test.go
index 3b6093cba95b4..d5ca7598d684c 100644
--- a/parser/auth/mysql_native_password_test.go
+++ b/parser/auth/mysql_native_password_test.go
@@ -20,21 +20,18 @@ import (
 )
 
 func TestEncodePassword(t *testing.T) {
-	t.Parallel()
 	pwd := "123"
 	require.Equal(t, "*23AE809DDACAF96AF0FD78ED04B6A265E05AA257", EncodePassword(pwd))
 	require.Equal(t, EncodePasswordBytes([]byte(pwd)), EncodePassword(pwd))
 }
 
 func TestDecodePassword(t *testing.T) {
-	t.Parallel()
 	x, err := DecodePassword(EncodePassword("123"))
 	require.NoError(t, err)
 	require.Equal(t, Sha1Hash(Sha1Hash([]byte("123"))), x)
 }
 
 func TestCheckScramble(t *testing.T) {
-	t.Parallel()
 	pwd := "abc"
 	salt := []byte{85, 92, 45, 22, 58, 79, 107, 6, 122, 125, 58, 80, 12, 90, 103, 32, 90, 10, 74, 82}
 	auth := []byte{24, 180, 183, 225, 166, 6, 81, 102, 70, 248, 199, 143, 91, 204, 169, 9, 161, 171, 203, 33}
diff --git a/parser/charset/charset_test.go b/parser/charset/charset_test.go
index 5edcee3bf6843..4a6777e1ddfa8 100644
--- a/parser/charset/charset_test.go
+++ b/parser/charset/charset_test.go
@@ -26,7 +26,6 @@ func testValidCharset(t *testing.T, charset string, collation string, expect boo
 }
 
 func TestValidCharset(t *testing.T) {
-	t.Parallel()
 	tests := []struct {
 		cs   string
 		co   string
@@ -61,7 +60,6 @@ func testGetDefaultCollation(t *testing.T, charset string, expectCollation strin
 }
 
 func TestGetDefaultCollation(t *testing.T) {
-	t.Parallel()
 	tests := []struct {
 		cs   string
 		co   string
@@ -94,7 +92,6 @@ func TestGetDefaultCollation(t *testing.T) {
 }
 
 func TestSupportedCollations(t *testing.T) {
-	t.Parallel()
 	// All supportedCollation are defined from their names
 	require.Equal(t, len(supportedCollationNames), len(supportedCollationNames))
 
@@ -112,7 +109,6 @@ func TestSupportedCollations(t *testing.T) {
 }
 
 func TestGetCharsetDesc(t *testing.T) {
-	t.Parallel()
 	tests := []struct {
 		cs     string
 		result string
@@ -138,7 +134,6 @@ func TestGetCharsetDesc(t *testing.T) {
 }
 
 func TestGetCollationByName(t *testing.T) {
-	t.Parallel()
 	for _, collation := range collations {
 		coll, err := GetCollationByName(collation.Name)
 		require.NoError(t, err)
diff --git a/parser/charset/encoding_test.go b/parser/charset/encoding_test.go
index 32ae8496c2e93..51f5b53b3e2fd 100644
--- a/parser/charset/encoding_test.go
+++ b/parser/charset/encoding_test.go
@@ -24,7 +24,6 @@ import (
 )
 
 func TestEncoding(t *testing.T) {
-	t.Parallel()
 	enc := charset.NewEncoding(charset.CharsetGBK)
 	require.Equal(t, charset.CharsetGBK, enc.Name())
 
diff --git a/parser/consistent_test.go b/parser/consistent_test.go
index 72c831536e6d0..621eea0a891eb 100644
--- a/parser/consistent_test.go
+++ b/parser/consistent_test.go
@@ -26,8 +26,6 @@ import (
 )
 
 func TestKeywordConsistent(t *testing.T) {
-	t.Parallel()
-
 	_, filename, _, _ := runtime.Caller(0)
 	parserFilename := path.Join(path.Dir(filename), "parser.y")
 	parserFile, err := os.Open(parserFilename)
diff --git a/parser/digester_test.go b/parser/digester_test.go
index 1fef35a3497a5..d69346e2faa7c 100644
--- a/parser/digester_test.go
+++ b/parser/digester_test.go
@@ -24,8 +24,6 @@ import (
 )
 
 func TestNormalize(t *testing.T) {
-	t.Parallel()
-
 	tests := []struct {
 		input  string
 		expect string
@@ -78,8 +76,6 @@ func TestNormalize(t *testing.T) {
 }
 
 func TestNormalizeDigest(t *testing.T) {
-	t.Parallel()
-
 	tests := []struct {
 		sql        string
 		normalized string
@@ -100,8 +96,6 @@ func TestNormalizeDigest(t *testing.T) {
 }
 
 func TestDigestHashEqForSimpleSQL(t *testing.T) {
-	t.Parallel()
-
 	sqlGroups := [][]string{
 		{"select * from b where id = 1", "select * from b where id = '1'", "select * from b where id =2"},
 		{"select 2 from b, c where c.id > 1", "select 4 from b, c where c.id > 23"},
@@ -121,8 +115,6 @@ func TestDigestHashEqForSimpleSQL(t *testing.T) {
 }
 
 func TestDigestHashNotEqForSimpleSQL(t *testing.T) {
-	t.Parallel()
-
 	sqlGroups := [][]string{
 		{"select * from b where id = 1", "select a from b where id = 1", "select * from d where bid =1"},
 	}
@@ -140,8 +132,6 @@ func TestDigestHashNotEqForSimpleSQL(t *testing.T) {
 }
 
 func TestGenDigest(t *testing.T) {
-	t.Parallel()
-
 	hash := genRandDigest("abc")
 	digest := parser.NewDigest(hash)
 	require.Equal(t, fmt.Sprintf("%x", hash), digest.String())
diff --git a/parser/format/format_test.go b/parser/format/format_test.go
index 72c14258f0e79..955b7fa46e965 100644
--- a/parser/format/format_test.go
+++ b/parser/format/format_test.go
@@ -31,7 +31,6 @@ func checkFormat(t *testing.T, f Formatter, buf *bytes.Buffer, str, expect strin
 }
 
 func TestFormat(t *testing.T) {
-	t.Parallel()
 	str := "abc%d%%e%i\nx\ny\n%uz\n"
 	buf := &bytes.Buffer{}
 	f := IndentFormatter(buf, "\t")
@@ -50,7 +49,6 @@ z
 }
 
 func TestRestoreCtx(t *testing.T) {
-	t.Parallel()
 	testCases := []struct {
 		flag   RestoreFlags
 		expect string
@@ -85,7 +83,6 @@ func TestRestoreCtx(t *testing.T) {
 }
 
 func TestRestoreSpecialComment(t *testing.T) {
-	t.Parallel()
 	var sb strings.Builder
 	sb.Reset()
 	ctx := NewRestoreCtx(RestoreTiDBSpecialComment, &sb)
diff --git a/parser/hintparser_test.go b/parser/hintparser_test.go
index 8ac22ec272123..5c252b2d4af78 100644
--- a/parser/hintparser_test.go
+++ b/parser/hintparser_test.go
@@ -25,8 +25,6 @@ import (
 )
 
 func TestParseHint(t *testing.T) {
-	t.Parallel()
-
 	testCases := []struct {
 		input  string
 		mode   mysql.SQLMode
diff --git a/parser/lexer_test.go b/parser/lexer_test.go
index b7ed1b976d1a8..676d0add40450 100644
--- a/parser/lexer_test.go
+++ b/parser/lexer_test.go
@@ -23,8 +23,6 @@ import (
 )
 
 func TestTokenID(t *testing.T) {
-	t.Parallel()
-
 	for str, tok := range tokenMap {
 		l := NewScanner(str)
 		var v yySymType
@@ -34,8 +32,6 @@ func TestTokenID(t *testing.T) {
 }
 
 func TestSingleChar(t *testing.T) {
-	t.Parallel()
-
 	table := []byte{'|', '&', '-', '+', '*', '/', '%', '^', '~', '(', ',', ')'}
 	for _, tok := range table {
 		l := NewScanner(string(tok))
@@ -56,8 +52,6 @@ type testLiteralValue struct {
 }
 
 func TestSingleCharOther(t *testing.T) {
-	t.Parallel()
-
 	table := []testCaseItem{
 		{"AT", identifier},
 		{"?", paramMarker},
@@ -69,8 +63,6 @@ func TestSingleCharOther(t *testing.T) {
 }
 
 func TestAtLeadingIdentifier(t *testing.T) {
-	t.Parallel()
-
 	table := []testCaseItem{
 		{"@", singleAtIdentifier},
 		{"@''", singleAtIdentifier},
@@ -96,8 +88,6 @@ func TestAtLeadingIdentifier(t *testing.T) {
 }
 
 func TestUnderscoreCS(t *testing.T) {
-	t.Parallel()
-
 	var v yySymType
 	scanner := NewScanner(`_utf8"string"`)
 	tok := scanner.Lex(&v)
@@ -113,8 +103,6 @@ func TestUnderscoreCS(t *testing.T) {
 }
 
 func TestLiteral(t *testing.T) {
-	t.Parallel()
-
 	table := []testCaseItem{
 		{`'''a'''`, stringLit},
 		{`''a''`, stringLit},
@@ -163,8 +151,6 @@ func TestLiteral(t *testing.T) {
 }
 
 func TestLiteralValue(t *testing.T) {
-	t.Parallel()
-
 	table := []testLiteralValue{
 		{`'''a'''`, `'a'`},
 		{`''a''`, ``},
@@ -239,8 +225,6 @@ func runLiteralTest(t *testing.T, table []testLiteralValue) {
 }
 
 func TestComment(t *testing.T) {
-	t.Parallel()
-
 	table := []testCaseItem{
 		{"-- select --\n1", intLit},
 		{"/*!40101 SET character_set_client = utf8 */;", set},
@@ -266,8 +250,6 @@ SELECT`, selectKwd},
 }
 
 func TestScanQuotedIdent(t *testing.T) {
-	t.Parallel()
-
 	l := NewScanner("`fk`")
 	l.r.peek()
 	tok, pos, lit := scanQuotedIdent(l)
@@ -277,8 +259,6 @@ func TestScanQuotedIdent(t *testing.T) {
 }
 
 func TestScanString(t *testing.T) {
-	t.Parallel()
-
 	table := []struct {
 		raw    string
 		expect string
@@ -314,8 +294,6 @@ func TestScanString(t *testing.T) {
 }
 
 func TestIdentifier(t *testing.T) {
-	t.Parallel()
-
 	replacementString := string(unicode.ReplacementChar) + "xxx"
 	table := [][2]string{
 		{`哈哈`, "哈哈"},
@@ -347,8 +325,6 @@ func TestIdentifier(t *testing.T) {
 }
 
 func TestSpecialComment(t *testing.T) {
-	t.Parallel()
-
 	l := NewScanner("/*!40101 select\n5*/")
 	tok, pos, lit := l.scan()
 	requires.Equal(t, identifier, tok)
@@ -362,8 +338,6 @@ func TestSpecialComment(t *testing.T) {
 }
 
 func TestFeatureIDsComment(t *testing.T) {
-	t.Parallel()
-
 	l := NewScanner("/*T![auto_rand] auto_random(5) */")
 	tok, pos, lit := l.scan()
 	requires.Equal(t, identifier, tok)
@@ -383,8 +357,6 @@ func TestFeatureIDsComment(t *testing.T) {
 }
 
 func TestOptimizerHint(t *testing.T) {
-	t.Parallel()
-
 	l := NewScanner("SELECT /*+ BKA(t1) */ 0;")
 	tokens := []struct {
 		tok   int
@@ -409,8 +381,6 @@ func TestOptimizerHint(t *testing.T) {
 }
 
 func TestOptimizerHintAfterCertainKeywordOnly(t *testing.T) {
-	t.Parallel()
-
 	tests := []struct {
 		input  string
 		tokens []int
@@ -491,8 +461,6 @@ func TestOptimizerHintAfterCertainKeywordOnly(t *testing.T) {
 }
 
 func TestInt(t *testing.T) {
-	t.Parallel()
-
 	tests := []struct {
 		input  string
 		expect uint64
@@ -522,8 +490,6 @@ func TestInt(t *testing.T) {
 }
 
 func TestSQLModeANSIQuotes(t *testing.T) {
-	t.Parallel()
-
 	tests := []struct {
 		input string
 		tok   int
@@ -556,8 +522,6 @@ func TestSQLModeANSIQuotes(t *testing.T) {
 }
 
 func TestIllegal(t *testing.T) {
-	t.Parallel()
-
 	table := []testCaseItem{
 		{"'", invalid},
 		{"'fu", invalid},
@@ -576,8 +540,6 @@ func TestIllegal(t *testing.T) {
 }
 
 func TestVersionDigits(t *testing.T) {
-	t.Parallel()
-
 	tests := []struct {
 		input    string
 		min      int
@@ -656,8 +618,6 @@ func TestVersionDigits(t *testing.T) {
 }
 
 func TestFeatureIDs(t *testing.T) {
-	t.Parallel()
-
 	tests := []struct {
 		input      string
 		featureIDs []string
diff --git a/parser/model/model_test.go b/parser/model/model_test.go
index c4968aa48855c..508eaa2713858 100644
--- a/parser/model/model_test.go
+++ b/parser/model/model_test.go
@@ -26,7 +26,6 @@ import (
 )
 
 func TestT(t *testing.T) {
-	t.Parallel()
 	abc := NewCIStr("aBC")
 	require.Equal(t, "aBC", abc.O)
 	require.Equal(t, "abc", abc.L)
@@ -34,7 +33,6 @@ func TestT(t *testing.T) {
 }
 
 func TestModelBasic(t *testing.T) {
-	t.Parallel()
 	column := &ColumnInfo{
 		ID:           1,
 		Name:         NewCIStr("c"),
@@ -140,7 +138,6 @@ func TestModelBasic(t *testing.T) {
 }
 
 func TestJobStartTime(t *testing.T) {
-	t.Parallel()
 	job := &Job{
 		ID:         123,
 		BinlogInfo: &HistoryInfo{},
@@ -150,7 +147,6 @@ func TestJobStartTime(t *testing.T) {
 }
 
 func TestJobCodec(t *testing.T) {
-	t.Parallel()
 	type A struct {
 		Name string
 	}
@@ -247,7 +243,6 @@ func TestJobCodec(t *testing.T) {
 }
 
 func TestState(t *testing.T) {
-	t.Parallel()
 	schemaTbl := []SchemaState{
 		StateDeleteOnly,
 		StateWriteOnly,
@@ -276,7 +271,6 @@ func TestState(t *testing.T) {
 }
 
 func TestString(t *testing.T) {
-	t.Parallel()
 	acts := []struct {
 		act    ActionType
 		result string
@@ -313,7 +307,6 @@ func TestString(t *testing.T) {
 }
 
 func TestUnmarshalCIStr(t *testing.T) {
-	t.Parallel()
 	var ci CIStr
 
 	// Test unmarshal CIStr from a single string.
@@ -333,7 +326,6 @@ func TestUnmarshalCIStr(t *testing.T) {
 }
 
 func TestDefaultValue(t *testing.T) {
-	t.Parallel()
 	srcCol := &ColumnInfo{
 		ID: 1,
 	}
@@ -411,8 +403,6 @@ func TestDefaultValue(t *testing.T) {
 }
 
 func TestPlacementSettingsString(t *testing.T) {
-	t.Parallel()
-
 	settings := &PlacementSettings{
 		PrimaryRegion: "us-east-1",
 		Regions:       "us-east-1,us-east-2",
diff --git a/parser/mysql/const_test.go b/parser/mysql/const_test.go
index ef54917c8bda5..3290e58ab11e5 100644
--- a/parser/mysql/const_test.go
+++ b/parser/mysql/const_test.go
@@ -20,7 +20,6 @@ import (
 )
 
 func TestSQLMode(t *testing.T) {
-	t.Parallel()
 	// ref https://dev.mysql.com/doc/internals/en/query-event.html#q-sql-mode-code,
 	hardCode := []struct {
 		code  SQLMode
diff --git a/parser/mysql/error_test.go b/parser/mysql/error_test.go
index 59c017decec27..846839001ddcd 100644
--- a/parser/mysql/error_test.go
+++ b/parser/mysql/error_test.go
@@ -20,7 +20,6 @@ import (
 )
 
 func TestSQLError(t *testing.T) {
-	t.Parallel()
 	e := NewErrf(ErrNoDB, "no db error", nil)
 	require.Greater(t, len(e.Error()), 0)
 
diff --git a/parser/mysql/privs_test.go b/parser/mysql/privs_test.go
index cebfe63fed30f..03d4352569b43 100644
--- a/parser/mysql/privs_test.go
+++ b/parser/mysql/privs_test.go
@@ -20,7 +20,6 @@ import (
 )
 
 func TestPrivString(t *testing.T) {
-	t.Parallel()
 	for i := 0; ; i++ {
 		p := PrivilegeType(1 << i)
 		if p > AllPriv {
@@ -31,7 +30,6 @@ func TestPrivString(t *testing.T) {
 }
 
 func TestPrivColumn(t *testing.T) {
-	t.Parallel()
 	for _, p := range AllGlobalPrivs {
 		require.NotEmptyf(t, p.ColumnString(), "%s", p)
 		np, ok := NewPrivFromColumn(p.ColumnString())
@@ -53,7 +51,6 @@ func TestPrivColumn(t *testing.T) {
 }
 
 func TestPrivSetString(t *testing.T) {
-	t.Parallel()
 	for _, p := range AllTablePrivs {
 		require.NotEmptyf(t, p.SetString(), "%s", p)
 		np, ok := NewPrivFromSetEnum(p.SetString())
@@ -69,7 +66,6 @@ func TestPrivSetString(t *testing.T) {
 }
 
 func TestPrivsHas(t *testing.T) {
-	t.Parallel()
 	// it is a simple helper, does not handle all&dynamic privs
 	privs := Privileges{AllPriv}
 	require.True(t, privs.Has(AllPriv))
@@ -83,7 +79,6 @@ func TestPrivsHas(t *testing.T) {
 }
 
 func TestPrivAllConsistency(t *testing.T) {
-	t.Parallel()
 	// AllPriv in mysql.user columns.
 	for priv := CreatePriv; priv != AllPriv; priv = priv << 1 {
 		_, ok := Priv2UserCol[priv]
diff --git a/parser/mysql/type_test.go b/parser/mysql/type_test.go
index f443b74f999e2..644f96bafb7ad 100644
--- a/parser/mysql/type_test.go
+++ b/parser/mysql/type_test.go
@@ -20,7 +20,6 @@ import (
 )
 
 func TestFlags(t *testing.T) {
-	t.Parallel()
 	require.True(t, HasNotNullFlag(NotNullFlag))
 	require.True(t, HasUniKeyFlag(UniqueKeyFlag))
 	require.True(t, HasNotNullFlag(NotNullFlag))
diff --git a/parser/parser_test.go b/parser/parser_test.go
index 7dc37aeba415e..b1b7b5ef89f17 100644
--- a/parser/parser_test.go
+++ b/parser/parser_test.go
@@ -33,8 +33,6 @@ import (
 )
 
 func TestSimple(t *testing.T) {
-	t.Parallel()
-
 	p := parser.New()
 
 	reservedKws := []string{
@@ -312,8 +310,6 @@ func TestSimple(t *testing.T) {
 }
 
 func TestSpecialComments(t *testing.T) {
-	t.Parallel()
-
 	p := parser.New()
 
 	// 1. Make sure /*! ... */ respects the same SQL mode.
@@ -462,8 +458,6 @@ func RunErrMsgTest(t *testing.T, table []testErrMsgCase) {
 }
 
 func TestDMLStmt(t *testing.T) {
-	t.Parallel()
-
 	table := []testCase{
 		{"", true, ""},
 		{";", true, ""},
@@ -1032,8 +1026,6 @@ AAAAAAAAAAAA5gm5Mg==
 }
 
 func TestDBAStmt(t *testing.T) {
-	t.Parallel()
-
 	table := []testCase{
 		// for SHOW statement
 		{"SHOW VARIABLES LIKE 'character_set_results'", true, "SHOW SESSION VARIABLES LIKE _UTF8MB4'character_set_results'"},
@@ -1287,8 +1279,6 @@ func TestDBAStmt(t *testing.T) {
 }
 
 func TestSetVariable(t *testing.T) {
-	t.Parallel()
-
 	table := []struct {
 		Input    string
 		Name     string
@@ -1332,8 +1322,6 @@ func TestSetVariable(t *testing.T) {
 }
 
 func TestFlushTable(t *testing.T) {
-	t.Parallel()
-
 	p := parser.New()
 	stmt, _, err := p.Parse("flush local tables tbl1,tbl2 with read lock", "", "")
 	require.NoError(t, err)
@@ -1346,8 +1334,6 @@ func TestFlushTable(t *testing.T) {
 }
 
 func TestFlushPrivileges(t *testing.T) {
-	t.Parallel()
-
 	p := parser.New()
 	stmt, _, err := p.Parse("flush privileges", "", "")
 	require.NoError(t, err)
@@ -1356,8 +1342,6 @@ func TestFlushPrivileges(t *testing.T) {
 }
 
 func TestExpression(t *testing.T) {
-	t.Parallel()
-
 	table := []testCase{
 		// sign expression
 		{"SELECT ++1", true, "SELECT ++1"},
@@ -1414,8 +1398,6 @@ func TestExpression(t *testing.T) {
 }
 
 func TestBuiltin(t *testing.T) {
-	t.Parallel()
-
 	table := []testCase{
 		// for builtin functions
 		{"SELECT POW(1, 2)", true, "SELECT POW(1, 2)"},
@@ -2152,8 +2134,6 @@ func TestBuiltin(t *testing.T) {
 }
 
 func TestIdentifier(t *testing.T) {
-	t.Parallel()
-
 	table := []testCase{
 		// for quote identifier
 		{"select `a`, `a.b`, `a b` from t", true, "SELECT `a`,`a.b`,`a b` FROM `t`"},
@@ -2209,8 +2189,6 @@ func TestIdentifier(t *testing.T) {
 }
 
 func TestDDL(t *testing.T) {
-	t.Parallel()
-
 	table := []testCase{
 		{"CREATE", false, ""},
 		{"CREATE TABLE", false, ""},
@@ -3462,8 +3440,6 @@ func TestDDL(t *testing.T) {
 }
 
 func TestHintError(t *testing.T) {
-	t.Parallel()
-
 	p := parser.New()
 	stmt, warns, err := p.Parse("select /*+ tidb_unknown(T1,t2) */ c1, c2 from t1, t2 where t1.c1 = t2.c1", "", "")
 	require.NoError(t, err)
@@ -3502,8 +3478,6 @@ func TestHintError(t *testing.T) {
 }
 
 func TestErrorMsg(t *testing.T) {
-	t.Parallel()
-
 	p := parser.New()
 	_, _, err := p.Parse("select1 1", "", "")
 	require.EqualError(t, err, "line 1 column 7 near \"select1 1\" ")
@@ -3602,8 +3576,6 @@ func TestErrorMsg(t *testing.T) {
 }
 
 func TestOptimizerHints(t *testing.T) {
-	t.Parallel()
-
 	p := parser.New()
 	// Test USE_INDEX
 	stmt, _, err := p.Parse("select /*+ USE_INDEX(T1,T2), use_index(t3,t4) */ c1, c2 from t1, t2 where t1.c1 = t2.c1", "", "")
@@ -4073,8 +4045,6 @@ func TestOptimizerHints(t *testing.T) {
 }
 
 func TestType(t *testing.T) {
-	t.Parallel()
-
 	table := []testCase{
 		// for time fsp
 		{"CREATE TABLE t( c1 TIME(2), c2 DATETIME(2), c3 TIMESTAMP(2) );", true, "CREATE TABLE `t` (`c1` TIME(2),`c2` DATETIME(2),`c3` TIMESTAMP(2))"},
@@ -4257,8 +4227,6 @@ func TestPrivilege(t *testing.T) {
 }
 
 func TestComment(t *testing.T) {
-	t.Parallel()
-
 	table := []testCase{
 		{"create table t (c int comment 'comment')", true, "CREATE TABLE `t` (`c` INT COMMENT 'comment')"},
 		{"create table t (c int) comment = 'comment'", true, "CREATE TABLE `t` (`c` INT) COMMENT = 'comment'"},
@@ -4285,8 +4253,6 @@ func TestComment(t *testing.T) {
 }
 
 func TestParserErrMsg(t *testing.T) {
-	t.Parallel()
-
 	commentMsgCases := []testErrMsgCase{
 		{"delete from t where a = 7 or 1=1/*' and b = 'p'", errors.New("near '/*' and b = 'p'' at line 1")},
 		{"delete from t where a = 7 or\n 1=1/*' and b = 'p'", errors.New("near '/*' and b = 'p'' at line 2")},
@@ -4321,8 +4287,6 @@ func (sc *subqueryChecker) Leave(inNode ast.Node) (node ast.Node, ok bool) {
 }
 
 func TestSubquery(t *testing.T) {
-	t.Parallel()
-
 	table := []testCase{
 		// for compare subquery
 		{"SELECT 1 > (select 1)", true, "SELECT 1>(SELECT 1)"},
@@ -4374,8 +4338,6 @@ func TestSubquery(t *testing.T) {
 }
 
 func TestSetOperator(t *testing.T) {
-	t.Parallel()
-
 	table := []testCase{
 		// union and union all
 		{"select c1 from t1 union select c2 from t2", true, "SELECT `c1` FROM `t1` UNION SELECT `c2` FROM `t2`"},
@@ -4501,8 +4463,6 @@ func checkOrderBy(t *testing.T, s ast.Node, hasOrderBy []bool, i int) int {
 }
 
 func TestUnionOrderBy(t *testing.T) {
-	t.Parallel()
-
 	p := parser.New()
 	p.EnableWindowFunc(false)
 
@@ -4536,8 +4496,6 @@ func TestUnionOrderBy(t *testing.T) {
 }
 
 func TestLikeEscape(t *testing.T) {
-	t.Parallel()
-
 	table := []testCase{
 		// for like escape
 		{`select "abc_" like "abc\\_" escape ''`, true, "SELECT _UTF8MB4'abc_' LIKE _UTF8MB4'abc\\_'"},
@@ -4551,8 +4509,6 @@ func TestLikeEscape(t *testing.T) {
 }
 
 func TestLockUnlockTables(t *testing.T) {
-	t.Parallel()
-
 	table := []testCase{
 		{`UNLOCK TABLES;`, true, "UNLOCK TABLES"},
 		{`LOCK TABLES t1 READ;`, true, "LOCK TABLES `t1` READ"},
@@ -4586,8 +4542,6 @@ func TestLockUnlockTables(t *testing.T) {
 }
 
 func TestIndexHint(t *testing.T) {
-	t.Parallel()
-
 	table := []testCase{
 		{`select * from t use index (primary)`, true, "SELECT * FROM `t` USE INDEX (`primary`)"},
 		{"select * from t use index (`primary`)", true, "SELECT * FROM `t` USE INDEX (`primary`)"},
@@ -4605,8 +4559,6 @@ func TestIndexHint(t *testing.T) {
 }
 
 func TestPriority(t *testing.T) {
-	t.Parallel()
-
 	table := []testCase{
 		{`select high_priority * from t`, true, "SELECT HIGH_PRIORITY * FROM `t`"},
 		{`select low_priority * from t`, true, "SELECT LOW_PRIORITY * FROM `t`"},
@@ -4634,8 +4586,6 @@ func TestPriority(t *testing.T) {
 }
 
 func TestSQLResult(t *testing.T) {
-	t.Parallel()
-
 	table := []testCase{
 		{`select SQL_BIG_RESULT c1 from t group by c1`, true, "SELECT SQL_BIG_RESULT `c1` FROM `t` GROUP BY `c1`"},
 		{`select SQL_SMALL_RESULT c1 from t group by c1`, true, "SELECT SQL_SMALL_RESULT `c1` FROM `t` GROUP BY `c1`"},
@@ -4649,8 +4599,6 @@ func TestSQLResult(t *testing.T) {
 }
 
 func TestSQLNoCache(t *testing.T) {
-	t.Parallel()
-
 	table := []testCase{
 		{`select SQL_NO_CACHE * from t`, false, ""},
 		{`select SQL_CACHE * from t`, true, "SELECT * FROM `t`"},
@@ -4668,8 +4616,6 @@ func TestSQLNoCache(t *testing.T) {
 }
 
 func TestEscape(t *testing.T) {
-	t.Parallel()
-
 	table := []testCase{
 		{`select """;`, false, ""},
 		{`select """";`, true, "SELECT _UTF8MB4'\"'"},
@@ -4683,8 +4629,6 @@ func TestEscape(t *testing.T) {
 }
 
 func TestExplain(t *testing.T) {
-	t.Parallel()
-
 	table := []testCase{
 		{"explain select c1 from t1", true, "EXPLAIN FORMAT = 'row' SELECT `c1` FROM `t1`"},
 		{"explain delete t1, t2 from t1 inner join t2 inner join t3 where t1.id=t2.id and t2.id=t3.id;", true, "EXPLAIN FORMAT = 'row' DELETE `t1`,`t2` FROM (`t1` JOIN `t2`) JOIN `t3` WHERE `t1`.`id`=`t2`.`id` AND `t2`.`id`=`t3`.`id`"},
@@ -4732,7 +4676,6 @@ func TestExplain(t *testing.T) {
 }
 
 func TestPrepare(t *testing.T) {
-	t.Parallel()
 	table := []testCase{
 		{"PREPARE pname FROM 'SELECT ?'", true, "PREPARE `pname` FROM 'SELECT ?'"},
 		{"PREPARE pname FROM @test", true, "PREPARE `pname` FROM @`test`"},
@@ -4742,7 +4685,6 @@ func TestPrepare(t *testing.T) {
 }
 
 func TestDeallocate(t *testing.T) {
-	t.Parallel()
 	table := []testCase{
 		{"DEALLOCATE PREPARE test", true, "DEALLOCATE PREPARE `test`"},
 		{"DEALLOCATE PREPARE ``", true, "DEALLOCATE PREPARE ``"},
@@ -4751,7 +4693,6 @@ func TestDeallocate(t *testing.T) {
 }
 
 func TestExecute(t *testing.T) {
-	t.Parallel()
 	table := []testCase{
 		{"EXECUTE test", true, "EXECUTE `test`"},
 		{"EXECUTE test USING @var1,@var2", true, "EXECUTE `test` USING @`var1`,@`var2`"},
@@ -4761,7 +4702,6 @@ func TestExecute(t *testing.T) {
 }
 
 func TestTrace(t *testing.T) {
-	t.Parallel()
 	table := []testCase{
 		{"trace begin", true, "TRACE START TRANSACTION"},
 		{"trace commit", true, "TRACE COMMIT"},
@@ -4783,7 +4723,6 @@ func TestTrace(t *testing.T) {
 }
 
 func TestBinding(t *testing.T) {
-	t.Parallel()
 	table := []testCase{
 		{"create global binding for select * from t using select * from t use index(a)", true, "CREATE GLOBAL BINDING FOR SELECT * FROM `t` USING SELECT * FROM `t` USE INDEX (`a`)"},
 		{"create session binding for select * from t using select * from t use index(a)", true, "CREATE SESSION BINDING FOR SELECT * FROM `t` USING SELECT * FROM `t` USE INDEX (`a`)"},
@@ -4857,7 +4796,6 @@ func TestBinding(t *testing.T) {
 }
 
 func TestView(t *testing.T) {
-	t.Parallel()
 	table := []testCase{
 		{"create view v as select * from t", true, "CREATE ALGORITHM = UNDEFINED DEFINER = CURRENT_USER SQL SECURITY DEFINER VIEW `v` AS SELECT * FROM `t`"},
 		{"create or replace view v as select * from t", true, "CREATE OR REPLACE ALGORITHM = UNDEFINED DEFINER = CURRENT_USER SQL SECURITY DEFINER VIEW `v` AS SELECT * FROM `t`"},
@@ -4964,7 +4902,6 @@ func TestView(t *testing.T) {
 }
 
 func TestTimestampDiffUnit(t *testing.T) {
-	t.Parallel()
 	// Test case for timestampdiff unit.
 	// TimeUnit should be unified to upper case.
 	p := parser.New()
@@ -5001,7 +4938,6 @@ func TestTimestampDiffUnit(t *testing.T) {
 }
 
 func TestFuncCallExprOffset(t *testing.T) {
-	t.Parallel()
 	// Test case for offset field on func call expr.
 	p := parser.New()
 	stmt, _, err := p.Parse("SELECT s.a(), b();", "", "")
@@ -5028,7 +4964,6 @@ func TestFuncCallExprOffset(t *testing.T) {
 }
 
 func TestSessionManage(t *testing.T) {
-	t.Parallel()
 	table := []testCase{
 		// Kill statement.
 		// See https://dev.mysql.com/doc/refman/5.7/en/kill.html
@@ -5047,7 +4982,6 @@ func TestSessionManage(t *testing.T) {
 }
 
 func TestParseShowOpenTables(t *testing.T) {
-	t.Parallel()
 	table := []testCase{
 		{"SHOW OPEN TABLES", true, "SHOW OPEN TABLES"},
 		{"SHOW OPEN TABLES IN test", true, "SHOW OPEN TABLES IN `test`"},
@@ -5057,7 +4991,6 @@ func TestParseShowOpenTables(t *testing.T) {
 }
 
 func TestSQLModeANSIQuotes(t *testing.T) {
-	t.Parallel()
 	p := parser.New()
 	p.SetSQLMode(mysql.ModeANSIQuotes)
 	tests := []string{
@@ -5071,7 +5004,6 @@ func TestSQLModeANSIQuotes(t *testing.T) {
 }
 
 func TestDDLStatements(t *testing.T) {
-	t.Parallel()
 	p := parser.New()
 	// Tests that whatever the charset it is define, we always assign utf8 charset and utf8_bin collate.
 	createTableStr := `CREATE TABLE t (
@@ -5151,7 +5083,6 @@ func TestDDLStatements(t *testing.T) {
 }
 
 func TestAnalyze(t *testing.T) {
-	t.Parallel()
 	table := []testCase{
 		{"analyze table t1", true, "ANALYZE TABLE `t1`"},
 		{"analyze table t1.*", false, ""},
@@ -5202,7 +5133,6 @@ func TestAnalyze(t *testing.T) {
 }
 
 func TestTableSample(t *testing.T) {
-	t.Parallel()
 	table := []testCase{
 		// positive test cases
 		{"select * from tbl tablesample system (50);", true, "SELECT * FROM `tbl` TABLESAMPLE SYSTEM (50)"},
@@ -5260,7 +5190,6 @@ func TestTableSample(t *testing.T) {
 }
 
 func TestGeneratedColumn(t *testing.T) {
-	t.Parallel()
 	tests := []struct {
 		input string
 		ok    bool
@@ -5290,7 +5219,6 @@ func TestGeneratedColumn(t *testing.T) {
 }
 
 func TestSetTransaction(t *testing.T) {
-	t.Parallel()
 	// Set transaction is equivalent to setting the global or session value of tx_isolation.
 	// For example:
 	// SET SESSION TRANSACTION ISOLATION LEVEL READ COMMITTED
@@ -5323,7 +5251,6 @@ func TestSetTransaction(t *testing.T) {
 }
 
 func TestSideEffect(t *testing.T) {
-	t.Parallel()
 	// This test cover a bug that parse an error SQL doesn't leave the parser in a
 	// clean state, cause the following SQL parse fail.
 	p := parser.New()
@@ -5335,8 +5262,6 @@ func TestSideEffect(t *testing.T) {
 }
 
 func TestTablePartition(t *testing.T) {
-	t.Parallel()
-
 	table := []testCase{
 		{"ALTER TABLE t1 TRUNCATE PARTITION p0", true, "ALTER TABLE `t1` TRUNCATE PARTITION `p0`"},
 		{"ALTER TABLE t1 TRUNCATE PARTITION p0, p1", true, "ALTER TABLE `t1` TRUNCATE PARTITION `p0`,`p1`"},
@@ -5537,7 +5462,6 @@ ENGINE=INNODB PARTITION BY LINEAR HASH (a) PARTITIONS 1;`, true, "CREATE TABLE `
 }
 
 func TestTablePartitionNameList(t *testing.T) {
-	t.Parallel()
 	table := []testCase{
 		{`select * from t partition (p0,p1)`, true, ""},
 	}
@@ -5559,7 +5483,6 @@ func TestTablePartitionNameList(t *testing.T) {
 }
 
 func TestNotExistsSubquery(t *testing.T) {
-	t.Parallel()
 	table := []testCase{
 		{`select * from t1 where not exists (select * from t2 where t1.a = t2.a)`, true, ""},
 	}
@@ -5577,7 +5500,6 @@ func TestNotExistsSubquery(t *testing.T) {
 }
 
 func TestWindowFunctionIdentifier(t *testing.T) {
-	t.Parallel()
 	var table []testCase
 	for key := range parser.WindowFuncTokenMapForTest {
 		table = append(table, testCase{fmt.Sprintf("select 1 %s", key), false, fmt.Sprintf("SELECT 1 AS `%s`", key)})
@@ -5591,7 +5513,6 @@ func TestWindowFunctionIdentifier(t *testing.T) {
 }
 
 func TestWindowFunctions(t *testing.T) {
-	t.Parallel()
 	table := []testCase{
 		// For window function descriptions.
 		// See https://dev.mysql.com/doc/refman/8.0/en/window-function-descriptions.html
@@ -5699,8 +5620,6 @@ func (wfc *windowFrameBoundChecker) Leave(inNode ast.Node) (node ast.Node, ok bo
 // For issue #51
 // See https://github.com/pingcap/parser/pull/51 for details
 func TestVisitFrameBound(t *testing.T) {
-	t.Parallel()
-
 	p := parser.New()
 	p.EnableWindowFunc(true)
 	table := []struct {
@@ -5724,7 +5643,6 @@ func TestVisitFrameBound(t *testing.T) {
 }
 
 func TestFieldText(t *testing.T) {
-	t.Parallel()
 	p := parser.New()
 	stmts, _, err := p.Parse("select a from t", "", "")
 	require.NoError(t, err)
@@ -5747,7 +5665,6 @@ func TestFieldText(t *testing.T) {
 
 // See https://github.com/pingcap/parser/issue/94
 func TestQuotedSystemVariables(t *testing.T) {
-	t.Parallel()
 	p := parser.New()
 
 	st, err := p.ParseOneStmt(
@@ -5809,8 +5726,6 @@ func TestQuotedSystemVariables(t *testing.T) {
 
 // See https://github.com/pingcap/parser/issue/95
 func TestQuotedVariableColumnName(t *testing.T) {
-	t.Parallel()
-
 	p := parser.New()
 
 	st, err := p.ParseOneStmt(
@@ -5841,8 +5756,6 @@ func TestQuotedVariableColumnName(t *testing.T) {
 }
 
 func TestCharset(t *testing.T) {
-	t.Parallel()
-
 	p := parser.New()
 
 	st, err := p.ParseOneStmt("ALTER SCHEMA GLOBAL DEFAULT CHAR SET utf8mb4", "", "")
@@ -5857,8 +5770,6 @@ func TestCharset(t *testing.T) {
 }
 
 func TestFulltextSearch(t *testing.T) {
-	t.Parallel()
-
 	p := parser.New()
 
 	st, err := p.ParseOneStmt("SELECT * FROM fulltext_test WHERE MATCH(content) AGAINST('search')", "", "")
@@ -5904,8 +5815,6 @@ func TestFulltextSearch(t *testing.T) {
 }
 
 func TestStartTransaction(t *testing.T) {
-	t.Parallel()
-
 	cases := []testCase{
 		{"START TRANSACTION READ WRITE", true, "START TRANSACTION"},
 		{"START TRANSACTION WITH CONSISTENT SNAPSHOT", true, "START TRANSACTION"},
@@ -5923,8 +5832,6 @@ func TestStartTransaction(t *testing.T) {
 }
 
 func TestSignedInt64OutOfRange(t *testing.T) {
-	t.Parallel()
-
 	p := parser.New()
 	cases := []string{
 		"recover table by job 18446744073709551612",
@@ -6034,8 +5941,6 @@ func (checker *nodeTextCleaner) Leave(in ast.Node) (out ast.Node, ok bool) {
 
 // For index advisor
 func TestIndexAdviseStmt(t *testing.T) {
-	t.Parallel()
-
 	table := []testCase{
 		{"INDEX ADVISE INFILE '/tmp/t.sql'", true, "INDEX ADVISE INFILE '/tmp/t.sql'"},
 		{"INDEX ADVISE LOCAL INFILE '/tmp/t.sql'", true, "INDEX ADVISE LOCAL INFILE '/tmp/t.sql'"},
@@ -6096,8 +6001,6 @@ func TestIndexAdviseStmt(t *testing.T) {
 
 // For BRIE
 func TestBRIE(t *testing.T) {
-	t.Parallel()
-
 	table := []testCase{
 		{"BACKUP DATABASE a TO 'local:///tmp/archive01/'", true, "BACKUP DATABASE `a` TO 'local:///tmp/archive01/'"},
 		{"BACKUP SCHEMA a TO 'local:///tmp/archive01/'", true, "BACKUP DATABASE `a` TO 'local:///tmp/archive01/'"},
@@ -6209,8 +6112,6 @@ func TestAsyncImport(t *testing.T) {
 }
 
 func TestStatisticsOps(t *testing.T) {
-	t.Parallel()
-
 	table := []testCase{
 		{"create statistics stats1 (cardinality) on t(a,b,c)", true, "CREATE STATISTICS `stats1` (CARDINALITY) ON `t`(`a`, `b`, `c`)"},
 		{"create statistics stats2 (dependency) on t(a,b)", true, "CREATE STATISTICS `stats2` (DEPENDENCY) ON `t`(`a`, `b`)"},
@@ -6241,8 +6142,6 @@ func TestStatisticsOps(t *testing.T) {
 }
 
 func TestHighNotPrecedenceMode(t *testing.T) {
-	t.Parallel()
-
 	p := parser.New()
 	var sb strings.Builder
 
@@ -6287,8 +6186,6 @@ func TestHighNotPrecedenceMode(t *testing.T) {
 
 // For CTE
 func TestCTE(t *testing.T) {
-	t.Parallel()
-
 	table := []testCase{
 		{"WITH `cte` AS (SELECT 1,2) SELECT `col1`,`col2` FROM `cte`", true, "WITH `cte` AS (SELECT 1,2) SELECT `col1`,`col2` FROM `cte`"},
 		{"WITH `cte` (col1, col2) AS (SELECT 1,2 UNION ALL SELECT 3,4) SELECT col1, col2 FROM cte;", true, "WITH `cte` (`col1`, `col2`) AS (SELECT 1,2 UNION ALL SELECT 3,4) SELECT `col1`,`col2` FROM `cte`"},
@@ -6313,7 +6210,6 @@ func TestCTE(t *testing.T) {
 }
 
 func TestAsOfClause(t *testing.T) {
-	t.Parallel()
 	table := []testCase{
 		{"SELECT * FROM `t` AS /* comment */ a;", true, "SELECT * FROM `t` AS `a`"},
 		{"SELECT * FROM `t` AS OF TIMESTAMP TIDB_BOUNDED_STALENESS(DATE_SUB(NOW(), INTERVAL 3 SECOND), NOW());", true, "SELECT * FROM `t` AS OF TIMESTAMP TIDB_BOUNDED_STALENESS(DATE_SUB(NOW(), INTERVAL 3 SECOND), NOW())"},
@@ -6331,8 +6227,6 @@ func TestAsOfClause(t *testing.T) {
 
 // For `PARTITION BY [LINEAR] KEY ALGORITHM` syntax
 func TestPartitionKeyAlgorithm(t *testing.T) {
-	t.Parallel()
-
 	table := []testCase{
 		{"CREATE TABLE t  (c1 integer ,c2 integer) PARTITION BY LINEAR KEY ALGORITHM = 1 (c1,c2) PARTITIONS 4", true, "CREATE TABLE `t` (`c1` INT,`c2` INT) PARTITION BY LINEAR KEY ALGORITHM = 1 (`c1`,`c2`) PARTITIONS 4"},
 		{"CREATE TABLE t  (c1 integer ,c2 integer) PARTITION BY LINEAR KEY ALGORITHM = -1 (c1,c2) PARTITIONS 4", false, ""},
@@ -6345,8 +6239,6 @@ func TestPartitionKeyAlgorithm(t *testing.T) {
 
 // server side help syntax
 func TestHelp(t *testing.T) {
-	t.Parallel()
-
 	table := []testCase{
 		{"HELP 'select'", true, "HELP 'select'"},
 	}
@@ -6355,8 +6247,6 @@ func TestHelp(t *testing.T) {
 }
 
 func TestRestoreBinOpWithBrackets(t *testing.T) {
-	t.Parallel()
-
 	cases := []testCase{
 		{"select mod(a+b, 4)+1", true, "SELECT (((`a` + `b`) % 4) + 1)"},
 		{"select mod( year(a) - abs(weekday(a) + dayofweek(a)), 4) + 1", true, "SELECT (((year(`a`) - abs((weekday(`a`) + dayofweek(`a`)))) % 4) + 1)"},
@@ -6400,8 +6290,6 @@ func TestRestoreBinOpWithBrackets(t *testing.T) {
 
 // For CTE bindings.
 func TestCTEBindings(t *testing.T) {
-	t.Parallel()
-
 	table := []testCase{
 		{"WITH `cte` AS (SELECT * from t) SELECT `col1`,`col2` FROM `cte`", true, "WITH `cte` AS (SELECT * FROM `test`.`t`) SELECT `col1`,`col2` FROM `cte`"},
 		{"WITH `cte` (col1, col2) AS (SELECT * from t UNION ALL SELECT 3,4) SELECT col1, col2 FROM cte;", true, "WITH `cte` (`col1`, `col2`) AS (SELECT * FROM `test`.`t` UNION ALL SELECT 3,4) SELECT `col1`,`col2` FROM `cte`"},
@@ -6459,7 +6347,6 @@ func TestCTEBindings(t *testing.T) {
 }
 
 func TestPlanReplayer(t *testing.T) {
-	t.Parallel()
 	table := []testCase{
 		{"PLAN REPLAYER DUMP EXPLAIN SELECT a FROM t", true, "PLAN REPLAYER DUMP EXPLAIN SELECT `a` FROM `t`"},
 		{"PLAN REPLAYER DUMP EXPLAIN SELECT * FROM t WHERE a > 10", true, "PLAN REPLAYER DUMP EXPLAIN SELECT * FROM `t` WHERE `a`>10"},
@@ -6493,7 +6380,6 @@ func TestPlanReplayer(t *testing.T) {
 }
 
 func TestGBKEncoding(t *testing.T) {
-	t.Parallel()
 	p := parser.New()
 	gbkEncoding, _ := charset.Lookup("gbk")
 	encoder := gbkEncoding.NewEncoder()
diff --git a/parser/types/field_type_test.go b/parser/types/field_type_test.go
index 9cc33560c9306..b552c7aa0a3fd 100644
--- a/parser/types/field_type_test.go
+++ b/parser/types/field_type_test.go
@@ -29,7 +29,6 @@ import (
 )
 
 func TestFieldType(t *testing.T) {
-	t.Parallel()
 	ft := NewFieldType(mysql.TypeDuration)
 	require.Equal(t, UnspecifiedLength, ft.Flen)
 	require.Equal(t, UnspecifiedLength, ft.Decimal)
@@ -197,7 +196,6 @@ func TestFieldType(t *testing.T) {
 }
 
 func TestHasCharsetFromStmt(t *testing.T) {
-	t.Parallel()
 	template := "CREATE TABLE t(a %s)"
 
 	types := []struct {
@@ -246,7 +244,6 @@ func TestHasCharsetFromStmt(t *testing.T) {
 }
 
 func TestEnumSetFlen(t *testing.T) {
-	t.Parallel()
 	p := parser.New()
 	cases := []struct {
 		sql string
@@ -279,7 +276,6 @@ func TestEnumSetFlen(t *testing.T) {
 }
 
 func TestFieldTypeEqual(t *testing.T) {
-	t.Parallel()
 	// Tp not equal
 	ft1 := NewFieldType(mysql.TypeDouble)
 	ft2 := NewFieldType(mysql.TypeFloat)
diff --git a/planner/cascades/enforcer_rules_test.go b/planner/cascades/enforcer_rules_test.go
index cd971149629d9..a71a7cbd9c680 100644
--- a/planner/cascades/enforcer_rules_test.go
+++ b/planner/cascades/enforcer_rules_test.go
@@ -24,8 +24,6 @@ import (
 )
 
 func TestGetEnforcerRules(t *testing.T) {
-	t.Parallel()
-
 	prop := &property.PhysicalProperty{}
 	group := memo.NewGroupWithSchema(nil, expression.NewSchema())
 	enforcers := GetEnforcerRules(group, prop)
@@ -42,7 +40,6 @@ func TestGetEnforcerRules(t *testing.T) {
 }
 
 func TestNewProperties(t *testing.T) {
-	t.Parallel()
 	prop := &property.PhysicalProperty{}
 	col := &expression.Column{}
 	group := memo.NewGroupWithSchema(nil, expression.NewSchema())
diff --git a/planner/cascades/integration_test.go b/planner/cascades/integration_test.go
index 144f00863b43a..426a4d467fa3b 100644
--- a/planner/cascades/integration_test.go
+++ b/planner/cascades/integration_test.go
@@ -25,8 +25,6 @@ import (
 )
 
 func TestSimpleProjDual(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -40,8 +38,6 @@ func TestSimpleProjDual(t *testing.T) {
 }
 
 func TestPKIsHandleRangeScan(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -72,8 +68,6 @@ func TestPKIsHandleRangeScan(t *testing.T) {
 }
 
 func TestIndexScan(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -104,8 +98,6 @@ func TestIndexScan(t *testing.T) {
 }
 
 func TestBasicShow(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -121,8 +113,6 @@ func TestBasicShow(t *testing.T) {
 }
 
 func TestSort(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -152,8 +142,6 @@ func TestSort(t *testing.T) {
 }
 
 func TestAggregation(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -186,8 +174,6 @@ func TestAggregation(t *testing.T) {
 }
 
 func TestPushdownDistinctEnable(t *testing.T) {
-	t.Parallel()
-
 	var input []string
 	var output []struct {
 		SQL    string
@@ -203,8 +189,6 @@ func TestPushdownDistinctEnable(t *testing.T) {
 }
 
 func TestPushdownDistinctDisable(t *testing.T) {
-	t.Parallel()
-
 	var input []string
 	var output []struct {
 		SQL    string
@@ -253,8 +237,6 @@ func doTestPushdownDistinct(t *testing.T, vars, input []string, output []struct
 }
 
 func TestSimplePlans(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -284,8 +266,6 @@ func TestSimplePlans(t *testing.T) {
 }
 
 func TestJoin(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -321,8 +301,6 @@ func TestJoin(t *testing.T) {
 }
 
 func TestApply(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -354,8 +332,6 @@ func TestApply(t *testing.T) {
 }
 
 func TestMemTableScan(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -382,8 +358,6 @@ func TestMemTableScan(t *testing.T) {
 }
 
 func TestTopN(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -413,8 +387,6 @@ func TestTopN(t *testing.T) {
 }
 
 func TestCascadePlannerHashedPartTable(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -449,8 +421,6 @@ func TestCascadePlannerHashedPartTable(t *testing.T) {
 }
 
 func TestInlineProjection(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
diff --git a/planner/cascades/optimize_test.go b/planner/cascades/optimize_test.go
index 6f3d69fcccd6d..104e1bd59b3e2 100644
--- a/planner/cascades/optimize_test.go
+++ b/planner/cascades/optimize_test.go
@@ -31,8 +31,6 @@ import (
 )
 
 func TestImplGroupZeroCost(t *testing.T) {
-	t.Parallel()
-
 	p := parser.New()
 	ctx := plannercore.MockContext()
 	is := infoschema.MockInfoSchema([]*model.TableInfo{plannercore.MockSignedTable()})
@@ -57,8 +55,6 @@ func TestImplGroupZeroCost(t *testing.T) {
 }
 
 func TestInitGroupSchema(t *testing.T) {
-	t.Parallel()
-
 	p := parser.New()
 	ctx := plannercore.MockContext()
 	is := infoschema.MockInfoSchema([]*model.TableInfo{plannercore.MockSignedTable()})
@@ -81,8 +77,6 @@ func TestInitGroupSchema(t *testing.T) {
 }
 
 func TestFillGroupStats(t *testing.T) {
-	t.Parallel()
-
 	p := parser.New()
 	ctx := plannercore.MockContext()
 	is := infoschema.MockInfoSchema([]*model.TableInfo{plannercore.MockSignedTable()})
@@ -104,8 +98,6 @@ func TestFillGroupStats(t *testing.T) {
 }
 
 func TestPreparePossibleProperties(t *testing.T) {
-	t.Parallel()
-
 	p := parser.New()
 	ctx := plannercore.MockContext()
 	is := infoschema.MockInfoSchema([]*model.TableInfo{plannercore.MockSignedTable()})
@@ -198,8 +190,6 @@ func (rule *fakeTransformation) OnTransform(old *memo.ExprIter) (newExprs []*mem
 }
 
 func TestAppliedRuleSet(t *testing.T) {
-	t.Parallel()
-
 	p := parser.New()
 	ctx := plannercore.MockContext()
 	is := infoschema.MockInfoSchema([]*model.TableInfo{plannercore.MockSignedTable()})
diff --git a/planner/cascades/stringer_test.go b/planner/cascades/stringer_test.go
index 229c47187e2ed..bdc4abb8486b6 100644
--- a/planner/cascades/stringer_test.go
+++ b/planner/cascades/stringer_test.go
@@ -29,8 +29,6 @@ import (
 )
 
 func TestGroupStringer(t *testing.T) {
-	t.Parallel()
-
 	optimizer := NewOptimizer()
 	optimizer.ResetTransformationRules(map[memo.Operand][]Transformation{
 		memo.OperandSelection: {
diff --git a/planner/cascades/transformation_rules_test.go b/planner/cascades/transformation_rules_test.go
index e7bb9babf3b6a..cfd25f42c1c38 100644
--- a/planner/cascades/transformation_rules_test.go
+++ b/planner/cascades/transformation_rules_test.go
@@ -62,8 +62,6 @@ func testGroupToString(t *testing.T, input []string, output []struct {
 }
 
 func TestAggPushDownGather(t *testing.T) {
-	t.Parallel()
-
 	optimizer := NewOptimizer()
 	optimizer.ResetTransformationRules(TransformationRuleBatch{
 		memo.OperandAggregation: {
@@ -116,8 +114,6 @@ func TestAggPushDownGather(t *testing.T) {
 }
 
 func TestPredicatePushDown(t *testing.T) {
-	t.Parallel()
-
 	optimizer := NewOptimizer()
 	optimizer.ResetTransformationRules(
 		TransformationRuleBatch{ // TiDB layer
@@ -159,8 +155,6 @@ func TestPredicatePushDown(t *testing.T) {
 }
 
 func TestTopNRules(t *testing.T) {
-	t.Parallel()
-
 	optimizer := NewOptimizer()
 	optimizer.ResetTransformationRules(
 		TransformationRuleBatch{ // TiDB layer
@@ -200,8 +194,6 @@ func TestTopNRules(t *testing.T) {
 }
 
 func TestProjectionElimination(t *testing.T) {
-	t.Parallel()
-
 	optimizer := NewOptimizer()
 	optimizer.ResetTransformationRules(TransformationRuleBatch{
 		memo.OperandProjection: {
@@ -222,8 +214,6 @@ func TestProjectionElimination(t *testing.T) {
 }
 
 func TestEliminateMaxMin(t *testing.T) {
-	t.Parallel()
-
 	optimizer := NewOptimizer()
 	optimizer.ResetTransformationRules(map[memo.Operand][]Transformation{
 		memo.OperandAggregation: {
@@ -243,8 +233,6 @@ func TestEliminateMaxMin(t *testing.T) {
 }
 
 func TestMergeAggregationProjection(t *testing.T) {
-	t.Parallel()
-
 	optimizer := NewOptimizer()
 	optimizer.ResetTransformationRules(map[memo.Operand][]Transformation{
 		memo.OperandAggregation: {
@@ -264,8 +252,6 @@ func TestMergeAggregationProjection(t *testing.T) {
 }
 
 func TestMergeAdjacentTopN(t *testing.T) {
-	t.Parallel()
-
 	optimizer := NewOptimizer()
 	optimizer.ResetTransformationRules(map[memo.Operand][]Transformation{
 		memo.OperandLimit: {
@@ -292,8 +278,6 @@ func TestMergeAdjacentTopN(t *testing.T) {
 }
 
 func TestMergeAdjacentLimit(t *testing.T) {
-	t.Parallel()
-
 	optimizer := NewOptimizer()
 	optimizer.ResetTransformationRules(TransformationRuleBatch{
 		memo.OperandLimit: {
@@ -314,8 +298,6 @@ func TestMergeAdjacentLimit(t *testing.T) {
 }
 
 func TestTransformLimitToTableDual(t *testing.T) {
-	t.Parallel()
-
 	optimizer := NewOptimizer()
 	optimizer.ResetTransformationRules(TransformationRuleBatch{
 		memo.OperandLimit: {
@@ -335,8 +317,6 @@ func TestTransformLimitToTableDual(t *testing.T) {
 }
 
 func TestPostTransformationRules(t *testing.T) {
-	t.Parallel()
-
 	optimizer := NewOptimizer()
 	optimizer.ResetTransformationRules(TransformationRuleBatch{
 		memo.OperandLimit: {
@@ -356,8 +336,6 @@ func TestPostTransformationRules(t *testing.T) {
 }
 
 func TestPushLimitDownTiKVSingleGather(t *testing.T) {
-	t.Parallel()
-
 	optimizer := NewOptimizer()
 	optimizer.ResetTransformationRules(map[memo.Operand][]Transformation{
 		memo.OperandLimit: {
@@ -383,8 +361,6 @@ func TestPushLimitDownTiKVSingleGather(t *testing.T) {
 }
 
 func TestEliminateOuterJoin(t *testing.T) {
-	t.Parallel()
-
 	optimizer := NewOptimizer()
 	optimizer.ResetTransformationRules(map[memo.Operand][]Transformation{
 		memo.OperandAggregation: {
@@ -407,8 +383,6 @@ func TestEliminateOuterJoin(t *testing.T) {
 }
 
 func TestTransformAggregateCaseToSelection(t *testing.T) {
-	t.Parallel()
-
 	optimizer := NewOptimizer()
 	optimizer.ResetTransformationRules(map[memo.Operand][]Transformation{
 		memo.OperandAggregation: {
@@ -428,8 +402,6 @@ func TestTransformAggregateCaseToSelection(t *testing.T) {
 }
 
 func TestTransformAggToProj(t *testing.T) {
-	t.Parallel()
-
 	optimizer := NewOptimizer()
 	optimizer.ResetTransformationRules(map[memo.Operand][]Transformation{
 		memo.OperandAggregation: {
@@ -452,8 +424,6 @@ func TestTransformAggToProj(t *testing.T) {
 }
 
 func TestDecorrelate(t *testing.T) {
-	t.Parallel()
-
 	optimizer := NewOptimizer()
 	optimizer.ResetTransformationRules(map[memo.Operand][]Transformation{
 		memo.OperandApply: {
@@ -474,8 +444,6 @@ func TestDecorrelate(t *testing.T) {
 }
 
 func TestInjectProj(t *testing.T) {
-	t.Parallel()
-
 	optimizer := NewOptimizer()
 	optimizer.ResetTransformationRules(map[memo.Operand][]Transformation{
 		memo.OperandLimit: {
diff --git a/planner/core/cache_test.go b/planner/core/cache_test.go
index 5255fe68c2f91..ff0ab53fa558b 100644
--- a/planner/core/cache_test.go
+++ b/planner/core/cache_test.go
@@ -23,7 +23,6 @@ import (
 )
 
 func TestCacheKey(t *testing.T) {
-	t.Parallel()
 	ctx := MockContext()
 	ctx.GetSessionVars().SnapshotTS = 0
 	ctx.GetSessionVars().SQLMode = mysql.ModeNone
diff --git a/planner/core/cacheable_checker_test.go b/planner/core/cacheable_checker_test.go
index 64d087ec31722..d4802db30f183 100644
--- a/planner/core/cacheable_checker_test.go
+++ b/planner/core/cacheable_checker_test.go
@@ -28,8 +28,6 @@ import (
 )
 
 func TestCacheable(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
diff --git a/planner/core/collect_column_stats_usage_test.go b/planner/core/collect_column_stats_usage_test.go
index 912765549fa7b..b270b6f7c1bfc 100644
--- a/planner/core/collect_column_stats_usage_test.go
+++ b/planner/core/collect_column_stats_usage_test.go
@@ -28,7 +28,6 @@ import (
 )
 
 func TestCollectPredicateColumns(t *testing.T) {
-	t.Parallel()
 	store, dom, clean := testkit.CreateMockStoreAndDomain(t)
 	defer clean()
 	tk := testkit.NewTestKit(t, store)
diff --git a/planner/core/exhaust_physical_plans_test.go b/planner/core/exhaust_physical_plans_test.go
index 853baf02671ff..2232d27e40621 100644
--- a/planner/core/exhaust_physical_plans_test.go
+++ b/planner/core/exhaust_physical_plans_test.go
@@ -47,7 +47,6 @@ func rewriteSimpleExpr(ctx sessionctx.Context, str string, schema *expression.Sc
 }
 
 func TestIndexJoinAnalyzeLookUpFilters(t *testing.T) {
-	t.Parallel()
 	ctx := MockContext()
 
 	ctx.GetSessionVars().PlanID = -1
diff --git a/planner/core/expression_test.go b/planner/core/expression_test.go
index a2dc8f7f3f4ae..0b207b7141c80 100644
--- a/planner/core/expression_test.go
+++ b/planner/core/expression_test.go
@@ -52,7 +52,6 @@ func runTests(t *testing.T, tests []testCase) {
 }
 
 func TestBetween(t *testing.T) {
-	t.Parallel()
 	tests := []testCase{
 		{exprStr: "1 between 2 and 3", resultStr: "0"},
 		{exprStr: "1 not between 2 and 3", resultStr: "1"},
@@ -64,7 +63,6 @@ func TestBetween(t *testing.T) {
 }
 
 func TestCaseWhen(t *testing.T) {
-	t.Parallel()
 	tests := []testCase{
 		{
 			exprStr:   "case 1 when 1 then 'str1' when 2 then 'str2' end",
@@ -103,7 +101,6 @@ func TestCaseWhen(t *testing.T) {
 }
 
 func TestCast(t *testing.T) {
-	t.Parallel()
 	f := types.NewFieldType(mysql.TypeLonglong)
 
 	expr := &ast.FuncCastExpr{
@@ -142,7 +139,6 @@ func TestCast(t *testing.T) {
 }
 
 func TestPatternIn(t *testing.T) {
-	t.Parallel()
 	tests := []testCase{
 		{
 			exprStr:   "1 not in (1, 2, 3)",
@@ -189,7 +185,6 @@ func TestPatternIn(t *testing.T) {
 }
 
 func TestIsNull(t *testing.T) {
-	t.Parallel()
 	tests := []testCase{
 		{
 			exprStr:   "1 IS NULL",
@@ -212,7 +207,6 @@ func TestIsNull(t *testing.T) {
 }
 
 func TestCompareRow(t *testing.T) {
-	t.Parallel()
 	tests := []testCase{
 		{
 			exprStr:   "row(1,2,3)=row(1,2,3)",
@@ -255,7 +249,6 @@ func TestCompareRow(t *testing.T) {
 }
 
 func TestIsTruth(t *testing.T) {
-	t.Parallel()
 	tests := []testCase{
 		{
 			exprStr:   "1 IS TRUE",
diff --git a/planner/core/find_best_task.go b/planner/core/find_best_task.go
index c23614e7c5935..59a182f9f8e7c 100644
--- a/planner/core/find_best_task.go
+++ b/planner/core/find_best_task.go
@@ -27,7 +27,7 @@ import (
 	"github.com/pingcap/tidb/parser/mysql"
 	"github.com/pingcap/tidb/planner/property"
 	"github.com/pingcap/tidb/planner/util"
-	"github.com/pingcap/tidb/sessionctx/stmtctx"
+	"github.com/pingcap/tidb/sessionctx"
 	"github.com/pingcap/tidb/statistics"
 	"github.com/pingcap/tidb/types"
 	tidbutil "github.com/pingcap/tidb/util"
@@ -1478,7 +1478,7 @@ func getMostCorrCol4Handle(exprs []expression.Expression, histColl *statistics.T
 }
 
 // getColumnRangeCounts estimates row count for each range respectively.
-func getColumnRangeCounts(sc *stmtctx.StatementContext, colID int64, ranges []*ranger.Range, histColl *statistics.HistColl, idxID int64) ([]float64, bool) {
+func getColumnRangeCounts(sctx sessionctx.Context, colID int64, ranges []*ranger.Range, histColl *statistics.HistColl, idxID int64) ([]float64, bool) {
 	var err error
 	var count float64
 	rangeCounts := make([]float64, len(ranges))
@@ -1488,13 +1488,13 @@ func getColumnRangeCounts(sc *stmtctx.StatementContext, colID int64, ranges []*r
 			if idxHist == nil || idxHist.IsInvalid(false) {
 				return nil, false
 			}
-			count, err = histColl.GetRowCountByIndexRanges(sc, idxID, []*ranger.Range{ran})
+			count, err = histColl.GetRowCountByIndexRanges(sctx, idxID, []*ranger.Range{ran})
 		} else {
 			colHist, ok := histColl.Columns[colID]
-			if !ok || colHist.IsInvalid(sc, false) {
+			if !ok || colHist.IsInvalid(sctx, false) {
 				return nil, false
 			}
-			count, err = histColl.GetRowCountByColumnRanges(sc, colID, []*ranger.Range{ran})
+			count, err = histColl.GetRowCountByColumnRanges(sctx, colID, []*ranger.Range{ran})
 		}
 		if err != nil {
 			return nil, false
@@ -1564,7 +1564,6 @@ func (ds *DataSource) crossEstimateRowCount(path *util.AccessPath, conds []expre
 	if len(accessConds) == 0 {
 		return 0, false, corr
 	}
-	sc := ds.ctx.GetSessionVars().StmtCtx
 	ranges, err := ranger.BuildColumnRange(accessConds, ds.ctx, col.RetType, types.UnspecifiedLength)
 	if len(ranges) == 0 || err != nil {
 		return 0, err == nil, corr
@@ -1573,7 +1572,7 @@ func (ds *DataSource) crossEstimateRowCount(path *util.AccessPath, conds []expre
 	if !idxExists {
 		idxID = -1
 	}
-	rangeCounts, ok := getColumnRangeCounts(sc, colID, ranges, ds.tableStats.HistColl, idxID)
+	rangeCounts, ok := getColumnRangeCounts(ds.ctx, colID, ranges, ds.tableStats.HistColl, idxID)
 	if !ok {
 		return 0, false, corr
 	}
@@ -1583,9 +1582,9 @@ func (ds *DataSource) crossEstimateRowCount(path *util.AccessPath, conds []expre
 	}
 	var rangeCount float64
 	if idxExists {
-		rangeCount, err = ds.tableStats.HistColl.GetRowCountByIndexRanges(sc, idxID, convertedRanges)
+		rangeCount, err = ds.tableStats.HistColl.GetRowCountByIndexRanges(ds.ctx, idxID, convertedRanges)
 	} else {
-		rangeCount, err = ds.tableStats.HistColl.GetRowCountByColumnRanges(sc, colID, convertedRanges)
+		rangeCount, err = ds.tableStats.HistColl.GetRowCountByColumnRanges(ds.ctx, colID, convertedRanges)
 	}
 	if err != nil {
 		return 0, false, corr
diff --git a/planner/core/indexmerge_test.go b/planner/core/indexmerge_test.go
index 13827af5d1f23..28118728b41e7 100644
--- a/planner/core/indexmerge_test.go
+++ b/planner/core/indexmerge_test.go
@@ -58,7 +58,6 @@ func getIndexMergePathDigest(paths []*util.AccessPath, startIndex int) string {
 }
 
 func TestIndexMergePathGeneration(t *testing.T) {
-	t.Parallel()
 	var input, output []string
 	indexMergeSuiteData.GetTestCases(t, &input, &output)
 	ctx := context.TODO()
diff --git a/planner/core/integration_partition_test.go b/planner/core/integration_partition_test.go
index b4faf61f64bcb..d463d05c45754 100644
--- a/planner/core/integration_partition_test.go
+++ b/planner/core/integration_partition_test.go
@@ -31,7 +31,6 @@ import (
 )
 
 func TestListPartitionPushDown(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 	tk := testkit.NewTestKit(t, store)
@@ -64,7 +63,6 @@ func TestListPartitionPushDown(t *testing.T) {
 }
 
 func TestListColVariousTypes(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -107,7 +105,6 @@ func TestListColVariousTypes(t *testing.T) {
 }
 
 func TestListPartitionPruning(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -151,7 +148,6 @@ func TestListPartitionPruning(t *testing.T) {
 }
 
 func TestListPartitionFunctions(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -190,7 +186,6 @@ func TestListPartitionOrderLimit(t *testing.T) {
 		t.Skip("skip race test")
 	}
 
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -254,7 +249,6 @@ func TestListPartitionAgg(t *testing.T) {
 		t.Skip("skip race test")
 	}
 
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -314,7 +308,6 @@ func TestListPartitionAgg(t *testing.T) {
 }
 
 func TestListPartitionDML(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -376,7 +369,6 @@ func TestListPartitionDML(t *testing.T) {
 }
 
 func TestListPartitionCreation(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -440,7 +432,6 @@ func TestListPartitionCreation(t *testing.T) {
 }
 
 func TestListPartitionDDL(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -495,7 +486,6 @@ func TestListPartitionDDL(t *testing.T) {
 }
 
 func TestListPartitionOperations(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -583,7 +573,6 @@ func TestListPartitionOperations(t *testing.T) {
 }
 
 func TestListPartitionPrivilege(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -623,7 +612,6 @@ func TestListPartitionPrivilege(t *testing.T) {
 }
 
 func TestListPartitionShardBits(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -655,7 +643,6 @@ func TestListPartitionShardBits(t *testing.T) {
 }
 
 func TestListPartitionSplitRegion(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -689,7 +676,6 @@ func TestListPartitionSplitRegion(t *testing.T) {
 }
 
 func TestListPartitionView(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -734,7 +720,6 @@ func TestListPartitionView(t *testing.T) {
 }
 
 func TestListPartitionAutoIncre(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -780,7 +765,6 @@ func TestListPartitionAutoIncre(t *testing.T) {
 }
 
 func TestListPartitionAutoRandom(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -816,7 +800,6 @@ func TestListPartitionAutoRandom(t *testing.T) {
 }
 
 func TestListPartitionInvisibleIdx(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -836,7 +819,6 @@ func TestListPartitionInvisibleIdx(t *testing.T) {
 }
 
 func TestListPartitionCTE(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -864,7 +846,6 @@ func TestListPartitionCTE(t *testing.T) {
 }
 
 func TestListPartitionTempTable(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -882,7 +863,6 @@ func TestListPartitionTempTable(t *testing.T) {
 }
 
 func TestListPartitionAlterPK(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -917,7 +897,6 @@ func TestListPartitionRandomTransaction(t *testing.T) {
 		t.Skip("skip race test")
 	}
 
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -971,7 +950,6 @@ func TestListPartitionRandomTransaction(t *testing.T) {
 }
 
 func TestIssue27018(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -999,7 +977,6 @@ PARTITION BY LIST COLUMNS(col1) (
 }
 
 func TestIssue27017(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -1029,7 +1006,6 @@ PARTITION BY LIST COLUMNS(col1) (
 }
 
 func TestIssue27544(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -1047,7 +1023,6 @@ func TestIssue27544(t *testing.T) {
 }
 
 func TestIssue27012(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -1078,7 +1053,6 @@ PARTITION BY LIST COLUMNS(col1) (
 }
 
 func TestIssue27030(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -1101,7 +1075,6 @@ PARTITION BY LIST COLUMNS(col1) (
 }
 
 func TestIssue27070(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -1113,7 +1086,6 @@ func TestIssue27070(t *testing.T) {
 }
 
 func TestIssue27031(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -1132,7 +1104,6 @@ PARTITION BY LIST COLUMNS(col1) (
 }
 
 func TestIssue27493(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -1162,7 +1133,6 @@ func genListPartition(begin, end int) string {
 }
 
 func TestIssue27532(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
diff --git a/planner/core/logical_plans.go b/planner/core/logical_plans.go
index 212f10d65346a..5fe0426b5c15b 100644
--- a/planner/core/logical_plans.go
+++ b/planner/core/logical_plans.go
@@ -726,7 +726,6 @@ func (ds *DataSource) deriveCommonHandleTablePathStats(path *util.AccessPath, co
 	if len(conds) == 0 {
 		return nil
 	}
-	sc := ds.ctx.GetSessionVars().StmtCtx
 	if len(path.IdxCols) != 0 {
 		res, err := ranger.DetachCondAndBuildRangeForIndex(ds.ctx, conds, path.IdxCols, path.IdxColLens)
 		if err != nil {
@@ -744,7 +743,7 @@ func (ds *DataSource) deriveCommonHandleTablePathStats(path *util.AccessPath, co
 				path.ConstCols[i] = res.ColumnValues[i] != nil
 			}
 		}
-		path.CountAfterAccess, err = ds.tableStats.HistColl.GetRowCountByIndexRanges(sc, path.Index.ID, path.Ranges)
+		path.CountAfterAccess, err = ds.tableStats.HistColl.GetRowCountByIndexRanges(ds.ctx, path.Index.ID, path.Ranges)
 		if err != nil {
 			return err
 		}
@@ -785,7 +784,6 @@ func (ds *DataSource) deriveTablePathStats(path *util.AccessPath, conds []expres
 		return ds.deriveCommonHandleTablePathStats(path, conds, isIm)
 	}
 	var err error
-	sc := ds.ctx.GetSessionVars().StmtCtx
 	path.CountAfterAccess = float64(ds.statisticTable.Count)
 	path.TableFilters = conds
 	var pkCol *expression.Column
@@ -848,7 +846,7 @@ func (ds *DataSource) deriveTablePathStats(path *util.AccessPath, conds []expres
 	if err != nil {
 		return err
 	}
-	path.CountAfterAccess, err = ds.statisticTable.GetRowCountByIntColumnRanges(sc, pkCol.ID, path.Ranges)
+	path.CountAfterAccess, err = ds.statisticTable.GetRowCountByIntColumnRanges(ds.ctx, pkCol.ID, path.Ranges)
 	// If the `CountAfterAccess` is less than `stats.RowCount`, there must be some inconsistent stats info.
 	// We prefer the `stats.RowCount` because it could use more stats info to calculate the selectivity.
 	if path.CountAfterAccess < ds.stats.RowCount && !isIm {
@@ -858,7 +856,6 @@ func (ds *DataSource) deriveTablePathStats(path *util.AccessPath, conds []expres
 }
 
 func (ds *DataSource) fillIndexPath(path *util.AccessPath, conds []expression.Expression) error {
-	sc := ds.ctx.GetSessionVars().StmtCtx
 	path.Ranges = ranger.FullRange()
 	path.CountAfterAccess = float64(ds.statisticTable.Count)
 	path.IdxCols, path.IdxColLens = expression.IndexInfo2PrefixCols(ds.Columns, ds.schema.Columns, path.Index)
@@ -900,7 +897,7 @@ func (ds *DataSource) fillIndexPath(path *util.AccessPath, conds []expression.Ex
 				path.ConstCols[i] = res.ColumnValues[i] != nil
 			}
 		}
-		path.CountAfterAccess, err = ds.tableStats.HistColl.GetRowCountByIndexRanges(sc, path.Index.ID, path.Ranges)
+		path.CountAfterAccess, err = ds.tableStats.HistColl.GetRowCountByIndexRanges(ds.ctx, path.Index.ID, path.Ranges)
 		if err != nil {
 			return err
 		}
diff --git a/planner/core/rule_partition_processor.go b/planner/core/rule_partition_processor.go
index 7c3bbb565c69d..bb57b0fac33da 100644
--- a/planner/core/rule_partition_processor.go
+++ b/planner/core/rule_partition_processor.go
@@ -140,7 +140,7 @@ func (s *partitionProcessor) findUsedPartitions(ctx sessionctx.Context, tbl tabl
 	ranges := detachedResult.Ranges
 	used := make([]int, 0, len(ranges))
 	for _, r := range ranges {
-		if r.IsPointNullable(ctx.GetSessionVars().StmtCtx) {
+		if r.IsPointNullable(ctx) {
 			if !r.HighVal[0].IsNull() {
 				if len(r.HighVal) != len(partIdx) {
 					used = []int{-1}
@@ -473,7 +473,7 @@ func (l *listPartitionPruner) locateColumnPartitionsByCondition(cond expression.
 			return nil, true, nil
 		}
 		var locations []tables.ListPartitionLocation
-		if r.IsPointNullable(l.ctx.GetSessionVars().StmtCtx) {
+		if r.IsPointNullable(l.ctx) {
 			location, err := colPrune.LocatePartition(sc, r.HighVal[0])
 			if types.ErrOverflow.Equal(err) {
 				return nil, true, nil // return full-scan if over-flow
@@ -555,7 +555,7 @@ func (l *listPartitionPruner) findUsedListPartitions(conds []expression.Expressi
 	}
 	used := make(map[int]struct{}, len(ranges))
 	for _, r := range ranges {
-		if r.IsPointNullable(l.ctx.GetSessionVars().StmtCtx) {
+		if r.IsPointNullable(l.ctx) {
 			if len(r.HighVal) != len(exprCols) {
 				return l.fullRange, nil
 			}
diff --git a/planner/core/stats.go b/planner/core/stats.go
index 14a6a11a2c2d4..2e7fd14a67b8d 100644
--- a/planner/core/stats.go
+++ b/planner/core/stats.go
@@ -253,7 +253,7 @@ func (ds *DataSource) deriveStatsByFilter(conds expression.CNFExprs, filledPaths
 	}
 	stats := ds.tableStats.Scale(selectivity)
 	if ds.ctx.GetSessionVars().OptimizerSelectivityLevel >= 1 {
-		stats.HistColl = stats.HistColl.NewHistCollBySelectivity(ds.ctx.GetSessionVars().StmtCtx, nodes)
+		stats.HistColl = stats.HistColl.NewHistCollBySelectivity(ds.ctx, nodes)
 	}
 	return stats
 }
diff --git a/planner/memo/expr_iterator_test.go b/planner/memo/expr_iterator_test.go
index d0cec2ac2a659..6722466661c66 100644
--- a/planner/memo/expr_iterator_test.go
+++ b/planner/memo/expr_iterator_test.go
@@ -23,8 +23,6 @@ import (
 )
 
 func TestNewExprIterFromGroupElem(t *testing.T) {
-	t.Parallel()
-
 	ctx := plannercore.MockContext()
 	schema := expression.NewSchema()
 
@@ -67,8 +65,6 @@ func TestNewExprIterFromGroupElem(t *testing.T) {
 }
 
 func TestExprIterNext(t *testing.T) {
-	t.Parallel()
-
 	ctx := plannercore.MockContext()
 	schema := expression.NewSchema()
 
@@ -116,8 +112,6 @@ func TestExprIterNext(t *testing.T) {
 }
 
 func TestExprIterReset(t *testing.T) {
-	t.Parallel()
-
 	ctx := plannercore.MockContext()
 	schema := expression.NewSchema()
 
@@ -190,8 +184,6 @@ func TestExprIterReset(t *testing.T) {
 }
 
 func TestExprIterWithEngineType(t *testing.T) {
-	t.Parallel()
-
 	ctx := plannercore.MockContext()
 	schema := expression.NewSchema()
 
diff --git a/planner/memo/group_expr_test.go b/planner/memo/group_expr_test.go
index 5257a96a8511b..8744e55f9f4e4 100644
--- a/planner/memo/group_expr_test.go
+++ b/planner/memo/group_expr_test.go
@@ -25,7 +25,6 @@ import (
 )
 
 func TestNewGroupExpr(t *testing.T) {
-	t.Parallel()
 	p := &plannercore.LogicalLimit{}
 	expr := NewGroupExpr(p)
 	require.Equal(t, p, expr.ExprNode)
@@ -34,7 +33,6 @@ func TestNewGroupExpr(t *testing.T) {
 }
 
 func TestGroupExprFingerprint(t *testing.T) {
-	t.Parallel()
 	p := &plannercore.LogicalLimit{Count: 3}
 	expr := NewGroupExpr(p)
 	childGroup := NewGroupWithSchema(nil, expression.NewSchema())
diff --git a/planner/memo/group_test.go b/planner/memo/group_test.go
index 399c5d37f476b..c7d377f38d08b 100644
--- a/planner/memo/group_test.go
+++ b/planner/memo/group_test.go
@@ -29,8 +29,6 @@ import (
 )
 
 func TestNewGroup(t *testing.T) {
-	t.Parallel()
-
 	p := &plannercore.LogicalLimit{}
 	expr := NewGroupExpr(p)
 	g := NewGroupWithSchema(expr, expression.NewSchema())
@@ -42,7 +40,6 @@ func TestNewGroup(t *testing.T) {
 }
 
 func TestGroupInsert(t *testing.T) {
-	t.Parallel()
 	p := &plannercore.LogicalLimit{}
 	expr := NewGroupExpr(p)
 	g := NewGroupWithSchema(expr, expression.NewSchema())
@@ -52,8 +49,6 @@ func TestGroupInsert(t *testing.T) {
 }
 
 func TestGroupDelete(t *testing.T) {
-	t.Parallel()
-
 	p := &plannercore.LogicalLimit{}
 	expr := NewGroupExpr(p)
 	g := NewGroupWithSchema(expr, expression.NewSchema())
@@ -67,8 +62,6 @@ func TestGroupDelete(t *testing.T) {
 }
 
 func TestGroupDeleteAll(t *testing.T) {
-	t.Parallel()
-
 	ctx := plannercore.MockContext()
 	expr := NewGroupExpr(plannercore.LogicalSelection{}.Init(ctx, 0))
 	g := NewGroupWithSchema(expr, expression.NewSchema())
@@ -85,8 +78,6 @@ func TestGroupDeleteAll(t *testing.T) {
 }
 
 func TestGroupExists(t *testing.T) {
-	t.Parallel()
-
 	p := &plannercore.LogicalLimit{}
 	expr := NewGroupExpr(p)
 	g := NewGroupWithSchema(expr, expression.NewSchema())
@@ -97,8 +88,6 @@ func TestGroupExists(t *testing.T) {
 }
 
 func TestGroupFingerPrint(t *testing.T) {
-	t.Parallel()
-
 	p := parser.New()
 	stmt1, err := p.ParseOneStmt("select * from t where a > 1 and a < 100", "", "")
 	require.NoError(t, err)
@@ -154,8 +143,6 @@ func TestGroupFingerPrint(t *testing.T) {
 }
 
 func TestGroupGetFirstElem(t *testing.T) {
-	t.Parallel()
-
 	ctx := plannercore.MockContext()
 	expr0 := NewGroupExpr(plannercore.LogicalProjection{}.Init(ctx, 0))
 	expr1 := NewGroupExpr(plannercore.LogicalLimit{}.Init(ctx, 0))
@@ -186,8 +173,6 @@ func (impl *fakeImpl) AttachChildren(...Implementation) Implementation { return
 func (impl *fakeImpl) GetCostLimit(float64, ...Implementation) float64 { return 0 }
 
 func TestGetInsertGroupImpl(t *testing.T) {
-	t.Parallel()
-
 	g := NewGroupWithSchema(NewGroupExpr(plannercore.LogicalLimit{}.Init(plannercore.MockContext(), 0)), expression.NewSchema())
 	emptyProp := &property.PhysicalProperty{}
 	require.Nil(t, g.GetImpl(emptyProp))
@@ -201,8 +186,6 @@ func TestGetInsertGroupImpl(t *testing.T) {
 }
 
 func TestEngineTypeSet(t *testing.T) {
-	t.Parallel()
-
 	require.True(t, EngineAll.Contains(EngineTiDB))
 	require.True(t, EngineAll.Contains(EngineTiKV))
 	require.True(t, EngineAll.Contains(EngineTiFlash))
@@ -225,8 +208,6 @@ func TestEngineTypeSet(t *testing.T) {
 }
 
 func TestFirstElemAfterDelete(t *testing.T) {
-	t.Parallel()
-
 	ctx := plannercore.MockContext()
 	oldExpr := NewGroupExpr(plannercore.LogicalLimit{Count: 10}.Init(ctx, 0))
 	g := NewGroupWithSchema(oldExpr, expression.NewSchema())
@@ -242,8 +223,6 @@ func TestFirstElemAfterDelete(t *testing.T) {
 }
 
 func TestBuildKeyInfo(t *testing.T) {
-	t.Parallel()
-
 	p := parser.New()
 	ctx := plannercore.MockContext()
 	is := infoschema.MockInfoSchema([]*model.TableInfo{plannercore.MockSignedTable()})
@@ -291,8 +270,6 @@ func TestBuildKeyInfo(t *testing.T) {
 }
 
 func TestExploreMark(t *testing.T) {
-	t.Parallel()
-
 	mark := ExploreMark(0)
 	require.False(t, mark.Explored(0))
 	require.False(t, mark.Explored(1))
diff --git a/planner/memo/pattern_test.go b/planner/memo/pattern_test.go
index 9d0ee17039d49..b326fb8a97290 100644
--- a/planner/memo/pattern_test.go
+++ b/planner/memo/pattern_test.go
@@ -22,7 +22,6 @@ import (
 )
 
 func TestGetOperand(t *testing.T) {
-	t.Parallel()
 	require.Equal(t, OperandJoin, GetOperand(&plannercore.LogicalJoin{}))
 	require.Equal(t, OperandAggregation, GetOperand(&plannercore.LogicalAggregation{}))
 	require.Equal(t, OperandProjection, GetOperand(&plannercore.LogicalProjection{}))
@@ -40,8 +39,6 @@ func TestGetOperand(t *testing.T) {
 }
 
 func TestOperandMatch(t *testing.T) {
-	t.Parallel()
-
 	require.True(t, OperandAny.Match(OperandLimit))
 	require.True(t, OperandAny.Match(OperandSelection))
 	require.True(t, OperandAny.Match(OperandJoin))
@@ -66,8 +63,6 @@ func TestOperandMatch(t *testing.T) {
 }
 
 func TestNewPattern(t *testing.T) {
-	t.Parallel()
-
 	p := NewPattern(OperandAny, EngineAll)
 	require.Equal(t, OperandAny, p.Operand)
 	require.Nil(t, p.Children)
@@ -78,8 +73,6 @@ func TestNewPattern(t *testing.T) {
 }
 
 func TestPatternSetChildren(t *testing.T) {
-	t.Parallel()
-
 	p := NewPattern(OperandAny, EngineAll)
 	p.SetChildren(NewPattern(OperandLimit, EngineAll))
 	require.Len(t, p.Children, 1)
diff --git a/planner/util/path.go b/planner/util/path.go
index 76e6c5173793d..9a0b4207d1314 100644
--- a/planner/util/path.go
+++ b/planner/util/path.go
@@ -153,7 +153,7 @@ func isColEqCorColOrConstant(ctx sessionctx.Context, filter expression.Expressio
 func (path *AccessPath) OnlyPointRange(sctx sessionctx.Context) bool {
 	if path.IsIntHandlePath {
 		for _, ran := range path.Ranges {
-			if !ran.IsPointNullable(sctx.GetSessionVars().StmtCtx) {
+			if !ran.IsPointNullable(sctx) {
 				return false
 			}
 		}
diff --git a/planner/util/path_test.go b/planner/util/path_test.go
index dd25e9b519a76..c9053dcd4d114 100644
--- a/planner/util/path_test.go
+++ b/planner/util/path_test.go
@@ -77,7 +77,6 @@ func TestCompareCol2Len(t *testing.T) {
 }
 
 func TestOnlyPointRange(t *testing.T) {
-	t.Parallel()
 	sctx := core.MockContext()
 	nullDatum := types.MinNotNullDatum()
 	nullDatum.SetNull()
diff --git a/plugin/const_test.go b/plugin/const_test.go
index 89985068bc8a2..05b498eab50b4 100644
--- a/plugin/const_test.go
+++ b/plugin/const_test.go
@@ -22,7 +22,6 @@ import (
 )
 
 func TestConstToString(t *testing.T) {
-	t.Parallel()
 	kinds := map[fmt.Stringer]string{
 		Audit:                     "Audit",
 		Authentication:            "Authentication",
diff --git a/plugin/helper_test.go b/plugin/helper_test.go
index 3bf7d14cc600c..99a310fa69b2f 100644
--- a/plugin/helper_test.go
+++ b/plugin/helper_test.go
@@ -21,7 +21,6 @@ import (
 )
 
 func TestPluginDeclare(t *testing.T) {
-	t.Parallel()
 	auditRaw := &AuditManifest{Manifest: Manifest{}}
 	auditExport := ExportManifest(auditRaw)
 	audit2 := DeclareAuditManifest(auditExport)
@@ -44,7 +43,6 @@ func TestPluginDeclare(t *testing.T) {
 }
 
 func TestDecode(t *testing.T) {
-	t.Parallel()
 	failID := ID("fail")
 	_, _, err := failID.Decode()
 	require.Error(t, err)
diff --git a/plugin/spi_test.go b/plugin/spi_test.go
index 672656f6a200d..d5f8fbdcd4d25 100644
--- a/plugin/spi_test.go
+++ b/plugin/spi_test.go
@@ -24,7 +24,6 @@ import (
 )
 
 func TestExportManifest(t *testing.T) {
-	t.Parallel()
 	callRecorder := struct {
 		OnInitCalled      bool
 		NotifyEventCalled bool
diff --git a/privilege/privileges/cache_test.go b/privilege/privileges/cache_test.go
index a975d3f4dadac..4d796333664e5 100644
--- a/privilege/privileges/cache_test.go
+++ b/privilege/privileges/cache_test.go
@@ -28,7 +28,6 @@ import (
 )
 
 func TestLoadUserTable(t *testing.T) {
-	t.Parallel()
 	store, clean := newStore(t)
 	defer clean()
 
@@ -63,7 +62,6 @@ func TestLoadUserTable(t *testing.T) {
 }
 
 func TestLoadGlobalPrivTable(t *testing.T) {
-	t.Parallel()
 	store, clean := newStore(t)
 	defer clean()
 
@@ -91,7 +89,6 @@ func TestLoadGlobalPrivTable(t *testing.T) {
 }
 
 func TestLoadDBTable(t *testing.T) {
-	t.Parallel()
 	store, clean := newStore(t)
 	defer clean()
 
@@ -114,7 +111,6 @@ func TestLoadDBTable(t *testing.T) {
 }
 
 func TestLoadTablesPrivTable(t *testing.T) {
-	t.Parallel()
 	store, clean := newStore(t)
 	defer clean()
 
@@ -140,7 +136,6 @@ func TestLoadTablesPrivTable(t *testing.T) {
 }
 
 func TestLoadColumnsPrivTable(t *testing.T) {
-	t.Parallel()
 	store, clean := newStore(t)
 	defer clean()
 
@@ -166,7 +161,6 @@ func TestLoadColumnsPrivTable(t *testing.T) {
 }
 
 func TestLoadDefaultRoleTable(t *testing.T) {
-	t.Parallel()
 	store, clean := newStore(t)
 	defer clean()
 
@@ -189,7 +183,6 @@ func TestLoadDefaultRoleTable(t *testing.T) {
 }
 
 func TestPatternMatch(t *testing.T) {
-	t.Parallel()
 	store, clean := newStore(t)
 	defer clean()
 
@@ -230,7 +223,6 @@ func TestPatternMatch(t *testing.T) {
 }
 
 func TestHostMatch(t *testing.T) {
-	t.Parallel()
 	store, clean := newStore(t)
 	defer clean()
 
@@ -288,7 +280,6 @@ func TestHostMatch(t *testing.T) {
 }
 
 func TestCaseInsensitive(t *testing.T) {
-	t.Parallel()
 	store, clean := newStore(t)
 	defer clean()
 
@@ -310,7 +301,6 @@ func TestCaseInsensitive(t *testing.T) {
 }
 
 func TestLoadRoleGraph(t *testing.T) {
-	t.Parallel()
 	store, clean := newStore(t)
 	defer clean()
 
@@ -344,7 +334,6 @@ func TestLoadRoleGraph(t *testing.T) {
 }
 
 func TestRoleGraphBFS(t *testing.T) {
-	t.Parallel()
 	store, clean := newStore(t)
 	defer clean()
 
@@ -382,7 +371,6 @@ func TestRoleGraphBFS(t *testing.T) {
 }
 
 func TestFindAllUserEffectiveRoles(t *testing.T) {
-	t.Parallel()
 	store, clean := newStore(t)
 	defer clean()
 
@@ -422,7 +410,6 @@ func TestFindAllUserEffectiveRoles(t *testing.T) {
 }
 
 func TestAbnormalMySQLTable(t *testing.T) {
-	t.Parallel()
 	store, clean := newStore(t)
 	defer clean()
 
@@ -501,7 +488,6 @@ func TestAbnormalMySQLTable(t *testing.T) {
 }
 
 func TestSortUserTable(t *testing.T) {
-	t.Parallel()
 	var p privileges.MySQLPrivilege
 	p.User = []privileges.UserRecord{
 		privileges.NewUserRecord(`%`, "root"),
@@ -542,7 +528,6 @@ func TestSortUserTable(t *testing.T) {
 }
 
 func TestGlobalPrivValueRequireStr(t *testing.T) {
-	t.Parallel()
 	var (
 		none  = privileges.GlobalPrivValue{SSLType: privileges.SslTypeNone}
 		tls   = privileges.GlobalPrivValue{SSLType: privileges.SslTypeAny}
@@ -570,7 +555,6 @@ func checkUserRecord(t *testing.T, x, y []privileges.UserRecord) {
 }
 
 func TestDBIsVisible(t *testing.T) {
-	t.Parallel()
 	store, clean := newStore(t)
 	defer clean()
 
diff --git a/privilege/privileges/privileges_test.go b/privilege/privileges/privileges_test.go
index c4cee0cbf1ce2..d9b7d94b64b33 100644
--- a/privilege/privileges/privileges_test.go
+++ b/privilege/privileges/privileges_test.go
@@ -50,7 +50,6 @@ import (
 const dbName = "test"
 
 func TestCheckDBPrivilege(t *testing.T) {
-	t.Parallel()
 	store, clean := newStore(t)
 	defer clean()
 	rootSe := newSession(t, store, dbName)
@@ -80,7 +79,6 @@ func TestCheckDBPrivilege(t *testing.T) {
 }
 
 func TestCheckPointGetDBPrivilege(t *testing.T) {
-	t.Parallel()
 	store, clean := newStore(t)
 	defer clean()
 	rootSe := newSession(t, store, dbName)
@@ -100,7 +98,6 @@ func TestCheckPointGetDBPrivilege(t *testing.T) {
 }
 
 func TestIssue22946(t *testing.T) {
-	t.Parallel()
 	store, clean := newStore(t)
 	defer clean()
 	rootSe := newSession(t, store, dbName)
@@ -127,7 +124,6 @@ func TestIssue22946(t *testing.T) {
 }
 
 func TestCheckTablePrivilege(t *testing.T) {
-	t.Parallel()
 	store, clean := newStore(t)
 	defer clean()
 
@@ -164,7 +160,6 @@ func TestCheckTablePrivilege(t *testing.T) {
 }
 
 func TestCheckViewPrivilege(t *testing.T) {
-	t.Parallel()
 	store, clean := newStore(t)
 	defer clean()
 	rootSe := newSession(t, store, dbName)
@@ -187,7 +182,6 @@ func TestCheckViewPrivilege(t *testing.T) {
 }
 
 func TestCheckPrivilegeWithRoles(t *testing.T) {
-	t.Parallel()
 	store, clean := newStore(t)
 	defer clean()
 	rootSe := newSession(t, store, dbName)
@@ -222,7 +216,6 @@ func TestCheckPrivilegeWithRoles(t *testing.T) {
 }
 
 func TestShowGrants(t *testing.T) {
-	t.Parallel()
 	store, clean := newStore(t)
 	defer clean()
 
@@ -377,7 +370,6 @@ func TestShowGrants(t *testing.T) {
 // identity from mysql.user. In TiDB we now use the identity from mysql.user in error messages
 // for consistency.
 func TestErrorMessage(t *testing.T) {
-	t.Parallel()
 	store, clean := newStore(t)
 	defer clean()
 
@@ -402,7 +394,6 @@ func TestErrorMessage(t *testing.T) {
 }
 
 func TestShowColumnGrants(t *testing.T) {
-	t.Parallel()
 	store, clean := newStore(t)
 	defer clean()
 	se := newSession(t, store, dbName)
@@ -418,7 +409,6 @@ func TestShowColumnGrants(t *testing.T) {
 }
 
 func TestDropTablePrivileges(t *testing.T) {
-	t.Parallel()
 	store, clean := newStore(t)
 	defer clean()
 
@@ -446,7 +436,6 @@ func TestDropTablePrivileges(t *testing.T) {
 }
 
 func TestSetPasswdStmt(t *testing.T) {
-	t.Parallel()
 	store, clean := newStore(t)
 	defer clean()
 	se := newSession(t, store, dbName)
@@ -567,7 +556,6 @@ func TestAlterUserStmt(t *testing.T) {
 }
 
 func TestSelectViewSecurity(t *testing.T) {
-	t.Parallel()
 	store, clean := newStore(t)
 	defer clean()
 
@@ -594,7 +582,6 @@ func TestSelectViewSecurity(t *testing.T) {
 }
 
 func TestShowViewPriv(t *testing.T) {
-	t.Parallel()
 	store, clean := newStore(t)
 	defer clean()
 
@@ -691,7 +678,6 @@ func TestShowViewPriv(t *testing.T) {
 }
 
 func TestRoleAdminSecurity(t *testing.T) {
-	t.Parallel()
 	store, clean := newStore(t)
 	defer clean()
 
@@ -714,7 +700,6 @@ func TestRoleAdminSecurity(t *testing.T) {
 }
 
 func TestCheckCertBasedAuth(t *testing.T) {
-	t.Parallel()
 	store, clean := newStore(t)
 	defer clean()
 
@@ -951,7 +936,6 @@ func connectionState(issuer, subject pkix.Name, cipher uint16, opt ...func(c *x5
 }
 
 func TestCheckAuthenticate(t *testing.T) {
-	t.Parallel()
 	store, clean := newStore(t)
 	defer clean()
 
@@ -994,7 +978,6 @@ func TestCheckAuthenticate(t *testing.T) {
 }
 
 func TestUseDB(t *testing.T) {
-	t.Parallel()
 	store, clean := newStore(t)
 	defer clean()
 
@@ -1041,7 +1024,6 @@ func TestUseDB(t *testing.T) {
 }
 
 func TestRevokePrivileges(t *testing.T) {
-	t.Parallel()
 	store, clean := newStore(t)
 	defer clean()
 
@@ -1069,7 +1051,6 @@ func TestRevokePrivileges(t *testing.T) {
 }
 
 func TestSetGlobal(t *testing.T) {
-	t.Parallel()
 	store, clean := newStore(t)
 	defer clean()
 	se := newSession(t, store, dbName)
@@ -1086,7 +1067,6 @@ func TestSetGlobal(t *testing.T) {
 }
 
 func TestCreateDropUser(t *testing.T) {
-	t.Parallel()
 	store, clean := newStore(t)
 	defer clean()
 
@@ -1115,7 +1095,6 @@ func TestCreateDropUser(t *testing.T) {
 }
 
 func TestConfigPrivilege(t *testing.T) {
-	t.Parallel()
 	store, clean := newStore(t)
 	defer clean()
 
@@ -1142,7 +1121,6 @@ func TestConfigPrivilege(t *testing.T) {
 }
 
 func TestShowCreateTable(t *testing.T) {
-	t.Parallel()
 	store, clean := newStore(t)
 	defer clean()
 
@@ -1161,7 +1139,6 @@ func TestShowCreateTable(t *testing.T) {
 }
 
 func TestReplaceAndInsertOnDuplicate(t *testing.T) {
-	t.Parallel()
 	store, clean := newStore(t)
 	defer clean()
 
@@ -1204,7 +1181,6 @@ func TestReplaceAndInsertOnDuplicate(t *testing.T) {
 }
 
 func TestAnalyzeTable(t *testing.T) {
-	t.Parallel()
 	store, clean := newStore(t)
 	defer clean()
 
@@ -1245,7 +1221,6 @@ func TestAnalyzeTable(t *testing.T) {
 }
 
 func TestSystemSchema(t *testing.T) {
-	t.Parallel()
 	store, clean := newStore(t)
 	defer clean()
 
@@ -1283,7 +1258,6 @@ func TestSystemSchema(t *testing.T) {
 }
 
 func TestPerformanceSchema(t *testing.T) {
-	t.Parallel()
 	store, clean := newStore(t)
 	defer clean()
 
@@ -1318,7 +1292,6 @@ func TestPerformanceSchema(t *testing.T) {
 }
 
 func TestMetricsSchema(t *testing.T) {
-	t.Parallel()
 	store, clean := newStore(t)
 	defer clean()
 
@@ -1430,7 +1403,6 @@ func TestMetricsSchema(t *testing.T) {
 }
 
 func TestAdminCommand(t *testing.T) {
-	t.Parallel()
 	store, clean := newStore(t)
 	defer clean()
 
@@ -1453,7 +1425,6 @@ func TestAdminCommand(t *testing.T) {
 }
 
 func TestTableNotExistNoPermissions(t *testing.T) {
-	t.Parallel()
 	store, clean := newStore(t)
 	defer clean()
 
@@ -1502,7 +1473,6 @@ func TestTableNotExistNoPermissions(t *testing.T) {
 }
 
 func TestLoadDataPrivilege(t *testing.T) {
-	t.Parallel()
 	// Create file.
 	path := "/tmp/load_data_priv.csv"
 	fp, err := os.Create(path)
@@ -1537,7 +1507,6 @@ func TestLoadDataPrivilege(t *testing.T) {
 }
 
 func TestSelectIntoNoPermissions(t *testing.T) {
-	t.Parallel()
 	store, clean := newStore(t)
 	defer clean()
 
@@ -1550,7 +1519,6 @@ func TestSelectIntoNoPermissions(t *testing.T) {
 }
 
 func TestGetEncodedPassword(t *testing.T) {
-	t.Parallel()
 	store, clean := newStore(t)
 	defer clean()
 
@@ -1561,7 +1529,6 @@ func TestGetEncodedPassword(t *testing.T) {
 }
 
 func TestAuthHost(t *testing.T) {
-	t.Parallel()
 	store, clean := newStore(t)
 	defer clean()
 
@@ -1583,7 +1550,6 @@ func TestAuthHost(t *testing.T) {
 }
 
 func TestDefaultRoles(t *testing.T) {
-	t.Parallel()
 	store, clean := newStore(t)
 	defer clean()
 
@@ -1608,7 +1574,6 @@ func TestDefaultRoles(t *testing.T) {
 }
 
 func TestUserTableConsistency(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -1638,7 +1603,6 @@ func TestUserTableConsistency(t *testing.T) {
 }
 
 func TestFieldList(t *testing.T) { // Issue #14237 List fields RPC
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -1681,7 +1645,6 @@ func newSession(t *testing.T, store kv.Storage, dbName string) session.Session {
 }
 
 func TestDynamicPrivs(t *testing.T) {
-	t.Parallel()
 	store, clean := newStore(t)
 	defer clean()
 
@@ -1728,7 +1691,6 @@ func TestDynamicPrivs(t *testing.T) {
 }
 
 func TestDynamicGrantOption(t *testing.T) {
-	t.Parallel()
 	store, clean := newStore(t)
 	defer clean()
 
@@ -1818,7 +1780,6 @@ func TestSecurityEnhancedModeInfoschema(t *testing.T) {
 }
 
 func TestClusterConfigInfoschema(t *testing.T) {
-	t.Parallel()
 	store, clean := newStore(t)
 	defer clean()
 
@@ -1906,7 +1867,6 @@ func TestSecurityEnhancedModeStatusVars(t *testing.T) {
 	// So we can only test that the dynamic privilege is grantable.
 	// We will have to use an integration test to run SHOW STATUS LIKE 'tidb_gc_leader_desc'
 	// and verify if it appears.
-	t.Parallel()
 	store, clean := newStore(t)
 	defer clean()
 	tk := testkit.NewTestKit(t, store)
@@ -1963,7 +1923,6 @@ func TestSecurityEnhancedLocalBackupRestore(t *testing.T) {
 }
 
 func TestRenameUser(t *testing.T) {
-	t.Parallel()
 	store, clean := newStore(t)
 	defer clean()
 
@@ -2075,7 +2034,6 @@ func TestSecurityEnhancedModeSysVars(t *testing.T) {
 // TestViewDefiner tests that default roles are correctly applied in the algorithm definer
 // See: https://github.com/pingcap/tidb/issues/24414
 func TestViewDefiner(t *testing.T) {
-	t.Parallel()
 	store, clean := newStore(t)
 	defer clean()
 
@@ -2153,7 +2111,6 @@ func TestSecurityEnhancedModeRestrictedUsers(t *testing.T) {
 }
 
 func TestDynamicPrivsRegistration(t *testing.T) {
-	t.Parallel()
 	store, clean := newStore(t)
 	defer clean()
 
@@ -2196,7 +2153,6 @@ func TestDynamicPrivsRegistration(t *testing.T) {
 func TestInfoSchemaUserPrivileges(t *testing.T) {
 	// Being able to read all privileges from information_schema.user_privileges requires a very specific set of permissions.
 	// SUPER user is not sufficient. It was observed in MySQL to require SELECT on mysql.*
-	t.Parallel()
 	store, clean := newStore(t)
 	defer clean()
 
@@ -2255,7 +2211,6 @@ func TestInfoSchemaUserPrivileges(t *testing.T) {
 
 // Issues https://github.com/pingcap/tidb/issues/25972 and https://github.com/pingcap/tidb/issues/26451
 func TestGrantOptionAndRevoke(t *testing.T) {
-	t.Parallel()
 	store, clean := newStore(t)
 	defer clean()
 
@@ -2333,7 +2288,6 @@ func tearDownTest(t *testing.T, store kv.Storage, dbName string) {
 }
 
 func TestGrantReferences(t *testing.T) {
-	t.Parallel()
 	store, clean := newStore(t)
 	defer clean()
 
@@ -2359,7 +2313,6 @@ func TestGrantReferences(t *testing.T) {
 }
 
 func TestDashboardClientDynamicPriv(t *testing.T) {
-	t.Parallel()
 	store, clean := newStore(t)
 	defer clean()
 
@@ -2404,8 +2357,6 @@ func TestDashboardClientDynamicPriv(t *testing.T) {
 
 // https://github.com/pingcap/tidb/issues/27213
 func TestShowGrantsWithRolesAndDynamicPrivs(t *testing.T) {
-	t.Parallel()
-
 	store, clean := newStore(t)
 	defer clean()
 
@@ -2494,7 +2445,6 @@ func TestShowGrantsWithRolesAndDynamicPrivs(t *testing.T) {
 }
 
 func TestGrantLockTables(t *testing.T) {
-	t.Parallel()
 	store, clean := newStore(t)
 	defer clean()
 
@@ -2519,8 +2469,6 @@ func TestGrantLockTables(t *testing.T) {
 
 // https://github.com/pingcap/tidb/issues/27560
 func TestShowGrantsForCurrentUserUsingRole(t *testing.T) {
-	t.Parallel()
-
 	store, clean := newStore(t)
 	defer clean()
 
@@ -2572,7 +2520,6 @@ func TestShowGrantsForCurrentUserUsingRole(t *testing.T) {
 }
 
 func TestGrantPlacementAdminDynamicPriv(t *testing.T) {
-	t.Parallel()
 	store, clean := newStore(t)
 	defer clean()
 
@@ -2632,7 +2579,6 @@ func TestDBNameCaseSensitivityInTableLevel(t *testing.T) {
 }
 
 func TestInformationSchemaPlacmentRulesPrivileges(t *testing.T) {
-	t.Parallel()
 	store, clean := newStore(t)
 	defer clean()
 
@@ -2686,7 +2632,6 @@ func TestInformationSchemaPlacmentRulesPrivileges(t *testing.T) {
 }
 
 func TestGrantCreateTmpTables(t *testing.T) {
-	t.Parallel()
 	store, clean := newStore(t)
 	defer clean()
 
@@ -2711,7 +2656,6 @@ func TestGrantCreateTmpTables(t *testing.T) {
 }
 
 func TestCreateTmpTablesPriv(t *testing.T) {
-	t.Parallel()
 	store, clean := newStore(t)
 	defer clean()
 
@@ -2869,7 +2813,6 @@ func TestCreateTmpTablesPriv(t *testing.T) {
 }
 
 func TestRevokeSecondSyntax(t *testing.T) {
-	t.Parallel()
 	store, clean := newStore(t)
 	defer clean()
 
@@ -2886,7 +2829,6 @@ func TestRevokeSecondSyntax(t *testing.T) {
 }
 
 func TestGrantEvent(t *testing.T) {
-	t.Parallel()
 	store, clean := newStore(t)
 	defer clean()
 
@@ -2910,7 +2852,6 @@ func TestGrantEvent(t *testing.T) {
 }
 
 func TestGrantRoutine(t *testing.T) {
-	t.Parallel()
 	store, clean := newStore(t)
 	defer clean()
 
@@ -2936,7 +2877,6 @@ func TestGrantRoutine(t *testing.T) {
 }
 
 func TestIssue28675(t *testing.T) {
-	t.Parallel()
 	store, clean := newStore(t)
 	defer clean()
 
@@ -3002,7 +2942,6 @@ func TestSkipGrantTable(t *testing.T) {
 }
 
 func TestIssue29823(t *testing.T) {
-	t.Parallel()
 	store, clean := newStore(t)
 	defer clean()
 
diff --git a/server/column_test.go b/server/column_test.go
index 7e17c2facb414..9d54a643f7f7b 100644
--- a/server/column_test.go
+++ b/server/column_test.go
@@ -22,8 +22,6 @@ import (
 )
 
 func TestDumpColumn(t *testing.T) {
-	t.Parallel()
-
 	info := ColumnInfo{
 		Schema:             "testSchema",
 		Table:              "testTable",
@@ -52,8 +50,6 @@ func TestDumpColumn(t *testing.T) {
 }
 
 func TestColumnNameLimit(t *testing.T) {
-	t.Parallel()
-
 	aLongName := make([]byte, 0, 300)
 	for i := 0; i < 300; i++ {
 		aLongName = append(aLongName, 'a')
diff --git a/server/conn_test.go b/server/conn_test.go
index cd35257d72454..a599ccee48702 100644
--- a/server/conn_test.go
+++ b/server/conn_test.go
@@ -44,7 +44,6 @@ import (
 )
 
 func TestMalformHandshakeHeader(t *testing.T) {
-	t.Parallel()
 	data := []byte{0x00}
 	var p handshakeResponse41
 	_, err := parseHandshakeResponseHeader(context.Background(), &p, data)
@@ -52,7 +51,6 @@ func TestMalformHandshakeHeader(t *testing.T) {
 }
 
 func TestParseHandshakeResponse(t *testing.T) {
-	t.Parallel()
 	// test data from http://dev.mysql.com/doc/internals/en/connection-phase-packets.html#packet-Protocol::HandshakeResponse41
 	data := []byte{
 		0x85, 0xa2, 0x1e, 0x00, 0x00, 0x00, 0x00, 0x40, 0x08, 0x00, 0x00, 0x00,
@@ -120,7 +118,6 @@ func TestParseHandshakeResponse(t *testing.T) {
 }
 
 func TestIssue1768(t *testing.T) {
-	t.Parallel()
 	// this data is from captured handshake packet, using mysql client.
 	// TiDB should handle authorization correctly, even mysql client set
 	// the ClientPluginAuthLenencClientData capability.
@@ -147,7 +144,6 @@ func TestIssue1768(t *testing.T) {
 }
 
 func TestAuthSwitchRequest(t *testing.T) {
-	t.Parallel()
 	// this data is from a MySQL 8.0 client
 	data := []byte{
 		0x85, 0xa6, 0xff, 0x1, 0x0, 0x0, 0x0, 0x1, 0x21, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0,
@@ -173,8 +169,6 @@ func TestAuthSwitchRequest(t *testing.T) {
 }
 
 func TestInitialHandshake(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -227,8 +221,6 @@ type dispatchInput struct {
 }
 
 func TestDispatch(t *testing.T) {
-	t.Parallel()
-
 	userData := append([]byte("root"), 0x0, 0x0)
 	userData = append(userData, []byte("test")...)
 	userData = append(userData, 0x0)
@@ -348,8 +340,6 @@ func TestDispatch(t *testing.T) {
 }
 
 func TestDispatchClientProtocol41(t *testing.T) {
-	t.Parallel()
-
 	userData := append([]byte("root"), 0x0, 0x0)
 	userData = append(userData, []byte("test")...)
 	userData = append(userData, 0x0)
@@ -524,8 +514,6 @@ func testDispatch(t *testing.T, inputs []dispatchInput, capability uint32) {
 }
 
 func TestGetSessionVarsWaitTimeout(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -560,8 +548,6 @@ func mapBelong(m1, m2 map[string]string) bool {
 }
 
 func TestConnExecutionTimeout(t *testing.T) {
-	t.Parallel()
-
 	store, dom, clean := testkit.CreateMockStoreAndDomain(t)
 	defer clean()
 
@@ -637,8 +623,6 @@ func TestConnExecutionTimeout(t *testing.T) {
 }
 
 func TestShutDown(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -654,8 +638,6 @@ func TestShutDown(t *testing.T) {
 }
 
 func TestShutdownOrNotify(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 	se, err := session.CreateSession4Test(store)
@@ -686,8 +668,6 @@ type snapshotCache interface {
 }
 
 func TestPrefetchPointKeys(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -749,8 +729,6 @@ func testGetTableByName(t *testing.T, ctx sessionctx.Context, db, table string)
 }
 
 func TestTiFlashFallback(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t,
 		mockstore.WithClusterInspector(func(c testutils.Cluster) {
 			mockCluster := c.(*unistore.Cluster)
@@ -881,8 +859,6 @@ func testFallbackWork(t *testing.T, tk *testkit.TestKit, cc *clientConn, sql str
 
 // For issue https://github.com/pingcap/tidb/issues/25069
 func TestShowErrors(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 	cc := &clientConn{
diff --git a/server/driver_tidb_test.go b/server/driver_tidb_test.go
index 4842466cd509d..b7126b31e00b4 100644
--- a/server/driver_tidb_test.go
+++ b/server/driver_tidb_test.go
@@ -42,8 +42,6 @@ func createColumnByTypeAndLen(tp byte, len uint32) *ColumnInfo {
 	}
 }
 func TestConvertColumnInfo(t *testing.T) {
-	t.Parallel()
-
 	// Test "mysql.TypeBit", for: https://github.com/pingcap/tidb/issues/5405.
 	resultField := ast.ResultField{
 		Column: &model.ColumnInfo{
diff --git a/server/http_handler_test.go b/server/http_handler_test.go
index 3278732a0059f..ac57db6425891 100644
--- a/server/http_handler_test.go
+++ b/server/http_handler_test.go
@@ -72,7 +72,6 @@ func createBasicHTTPHandlerTestSuite() *basicHTTPHandlerTestSuite {
 }
 
 func TestRegionIndexRange(t *testing.T) {
-	t.Parallel()
 	sTableID := int64(3)
 	sIndex := int64(11)
 	eTableID := int64(9)
@@ -143,7 +142,6 @@ func TestRegionIndexRange(t *testing.T) {
 }
 
 func TestRegionCommonHandleRange(t *testing.T) {
-	t.Parallel()
 	sTableID := int64(3)
 	indexValues := []types.Datum{
 		types.NewIntDatum(100),
@@ -179,7 +177,6 @@ func TestRegionCommonHandleRange(t *testing.T) {
 }
 
 func TestRegionIndexRangeWithEndNoLimit(t *testing.T) {
-	t.Parallel()
 	sTableID := int64(15)
 	startKey := tablecodec.GenTableRecordPrefix(sTableID)
 	endKey := []byte("z_aaaaafdfd")
@@ -197,7 +194,6 @@ func TestRegionIndexRangeWithEndNoLimit(t *testing.T) {
 }
 
 func TestRegionIndexRangeWithStartNoLimit(t *testing.T) {
-	t.Parallel()
 	eTableID := int64(9)
 	startKey := []byte("m_aaaaafdfd")
 	endKey := tablecodec.GenTableRecordPrefix(eTableID)
@@ -215,7 +211,6 @@ func TestRegionIndexRangeWithStartNoLimit(t *testing.T) {
 }
 
 func TestRegionsAPI(t *testing.T) {
-	t.Parallel()
 	ts := createBasicHTTPHandlerTestSuite()
 	ts.startServer(t)
 	defer ts.stopServer(t)
@@ -238,7 +233,6 @@ func TestRegionsAPI(t *testing.T) {
 }
 
 func TestRegionsAPIForClusterIndex(t *testing.T) {
-	t.Parallel()
 	ts := createBasicHTTPHandlerTestSuite()
 	ts.startServer(t)
 	defer ts.stopServer(t)
@@ -274,7 +268,6 @@ func TestRegionsAPIForClusterIndex(t *testing.T) {
 }
 
 func TestRangesAPI(t *testing.T) {
-	t.Parallel()
 	ts := createBasicHTTPHandlerTestSuite()
 	ts.startServer(t)
 	defer ts.stopServer(t)
@@ -314,7 +307,6 @@ func (ts *basicHTTPHandlerTestSuite) regionContainsTable(t *testing.T, regionID
 }
 
 func TestListTableRegions(t *testing.T) {
-	t.Parallel()
 	ts := createBasicHTTPHandlerTestSuite()
 	ts.startServer(t)
 	defer ts.stopServer(t)
@@ -341,7 +333,6 @@ func TestListTableRegions(t *testing.T) {
 }
 
 func TestListTableRanges(t *testing.T) {
-	t.Parallel()
 	ts := createBasicHTTPHandlerTestSuite()
 	ts.startServer(t)
 	defer ts.stopServer(t)
@@ -367,7 +358,6 @@ func TestListTableRanges(t *testing.T) {
 }
 
 func TestGetRegionByIDWithError(t *testing.T) {
-	t.Parallel()
 	ts := createBasicHTTPHandlerTestSuite()
 	ts.startServer(t)
 	defer ts.stopServer(t)
@@ -378,7 +368,6 @@ func TestGetRegionByIDWithError(t *testing.T) {
 }
 
 func TestBinlogRecover(t *testing.T) {
-	t.Parallel()
 	ts := createBasicHTTPHandlerTestSuite()
 	ts.startServer(t)
 	defer ts.stopServer(t)
@@ -558,7 +547,6 @@ func decodeKeyMvcc(closer io.ReadCloser, t *testing.T, valid bool) {
 }
 
 func TestGetTableMVCC(t *testing.T) {
-	t.Parallel()
 	ts := createBasicHTTPHandlerTestSuite()
 	ts.startServer(t)
 	ts.prepareData(t)
@@ -657,7 +645,6 @@ func TestGetTableMVCC(t *testing.T) {
 }
 
 func TestGetMVCCNotFound(t *testing.T) {
-	t.Parallel()
 	ts := createBasicHTTPHandlerTestSuite()
 	ts.startServer(t)
 	ts.prepareData(t)
@@ -675,7 +662,6 @@ func TestGetMVCCNotFound(t *testing.T) {
 }
 
 func TestDecodeColumnValue(t *testing.T) {
-	t.Parallel()
 	ts := createBasicHTTPHandlerTestSuite()
 	ts.startServer(t)
 	ts.prepareData(t)
@@ -742,7 +728,6 @@ func TestDecodeColumnValue(t *testing.T) {
 }
 
 func TestGetIndexMVCC(t *testing.T) {
-	t.Parallel()
 	ts := createBasicHTTPHandlerTestSuite()
 	ts.startServer(t)
 	ts.prepareData(t)
@@ -821,7 +806,6 @@ func TestGetIndexMVCC(t *testing.T) {
 }
 
 func TestGetSettings(t *testing.T) {
-	t.Parallel()
 	ts := createBasicHTTPHandlerTestSuite()
 	ts.startServer(t)
 	ts.prepareData(t)
@@ -843,7 +827,6 @@ func TestGetSettings(t *testing.T) {
 }
 
 func TestGetSchema(t *testing.T) {
-	t.Parallel()
 	ts := createBasicHTTPHandlerTestSuite()
 	ts.startServer(t)
 	ts.prepareData(t)
@@ -959,7 +942,6 @@ func TestGetSchema(t *testing.T) {
 }
 
 func TestAllHistory(t *testing.T) {
-	t.Parallel()
 	ts := createBasicHTTPHandlerTestSuite()
 	ts.startServer(t)
 	ts.prepareData(t)
@@ -996,7 +978,6 @@ func dummyRecord() *deadlockhistory.DeadlockRecord {
 }
 
 func TestPprof(t *testing.T) {
-	t.Parallel()
 	ts := createBasicHTTPHandlerTestSuite()
 	ts.startServer(t)
 	defer ts.stopServer(t)
@@ -1016,7 +997,6 @@ func TestPprof(t *testing.T) {
 }
 
 func TestHotRegionInfo(t *testing.T) {
-	t.Parallel()
 	ts := createBasicHTTPHandlerTestSuite()
 	ts.startServer(t)
 	defer ts.stopServer(t)
@@ -1027,7 +1007,6 @@ func TestHotRegionInfo(t *testing.T) {
 }
 
 func TestDebugZip(t *testing.T) {
-	t.Parallel()
 	ts := createBasicHTTPHandlerTestSuite()
 	ts.startServer(t)
 	defer ts.stopServer(t)
@@ -1041,7 +1020,6 @@ func TestDebugZip(t *testing.T) {
 }
 
 func TestCheckCN(t *testing.T) {
-	t.Parallel()
 	s := &Server{cfg: &config.Config{Security: config.Security{ClusterVerifyCN: []string{"a ", "b", "c"}}}}
 	tlsConfig := &tls.Config{}
 	s.setCNChecker(tlsConfig)
@@ -1055,7 +1033,6 @@ func TestCheckCN(t *testing.T) {
 }
 
 func TestDDLHookHandler(t *testing.T) {
-	t.Parallel()
 	ts := createBasicHTTPHandlerTestSuite()
 
 	ts.startServer(t)
diff --git a/server/mock_conn_test.go b/server/mock_conn_test.go
index 9eae5ad1003da..8bcadd0da1c06 100644
--- a/server/mock_conn_test.go
+++ b/server/mock_conn_test.go
@@ -24,8 +24,6 @@ import (
 )
 
 func TestMockConn(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 	server := CreateMockServer(t, store)
diff --git a/server/packetio_test.go b/server/packetio_test.go
index fbb5c7c2651eb..3f85059fe4b83 100644
--- a/server/packetio_test.go
+++ b/server/packetio_test.go
@@ -26,8 +26,6 @@ import (
 )
 
 func TestPacketIOWrite(t *testing.T) {
-	t.Parallel()
-
 	// Test write one packet
 	var outBuffer bytes.Buffer
 	pkt := &packetIO{bufWriter: bufio.NewWriter(&outBuffer)}
@@ -53,8 +51,6 @@ func TestPacketIOWrite(t *testing.T) {
 }
 
 func TestPacketIORead(t *testing.T) {
-	t.Parallel()
-
 	var inBuffer bytes.Buffer
 	_, err := inBuffer.Write([]byte{0x01, 0x00, 0x00, 0x00, 0x01})
 	require.NoError(t, err)
diff --git a/server/tidb_test.go b/server/tidb_test.go
index 1b8941c34a49f..5c0c2e9e189e1 100644
--- a/server/tidb_test.go
+++ b/server/tidb_test.go
@@ -140,13 +140,11 @@ func TestRegression(t *testing.T) {
 	ts, cleanup := createTidbTestSuite(t)
 	defer cleanup()
 	if regression {
-		t.Parallel()
 		ts.runTestRegression(t, nil, "Regression")
 	}
 }
 
 func TestUint64(t *testing.T) {
-	t.Parallel()
 	ts, cleanup := createTidbTestSuite(t)
 	defer cleanup()
 
@@ -154,7 +152,6 @@ func TestUint64(t *testing.T) {
 }
 
 func TestSpecialType(t *testing.T) {
-	t.Parallel()
 	ts, cleanup := createTidbTestSuite(t)
 	defer cleanup()
 
@@ -162,7 +159,6 @@ func TestSpecialType(t *testing.T) {
 }
 
 func TestPreparedString(t *testing.T) {
-	t.Parallel()
 	ts, cleanup := createTidbTestSuite(t)
 	defer cleanup()
 
@@ -170,7 +166,6 @@ func TestPreparedString(t *testing.T) {
 }
 
 func TestPreparedTimestamp(t *testing.T) {
-	t.Parallel()
 	ts, cleanup := createTidbTestSuite(t)
 	defer cleanup()
 
@@ -178,7 +173,6 @@ func TestPreparedTimestamp(t *testing.T) {
 }
 
 func TestConcurrentUpdate(t *testing.T) {
-	t.Parallel()
 	ts, cleanup := createTidbTestSuite(t)
 	defer cleanup()
 
@@ -186,7 +180,6 @@ func TestConcurrentUpdate(t *testing.T) {
 }
 
 func TestErrorCode(t *testing.T) {
-	t.Parallel()
 	ts, cleanup := createTidbTestSuite(t)
 	defer cleanup()
 
@@ -194,7 +187,6 @@ func TestErrorCode(t *testing.T) {
 }
 
 func TestAuth(t *testing.T) {
-	t.Parallel()
 	ts, cleanup := createTidbTestSuite(t)
 	defer cleanup()
 
@@ -203,7 +195,6 @@ func TestAuth(t *testing.T) {
 }
 
 func TestIssues(t *testing.T) {
-	t.Parallel()
 	ts, cleanup := createTidbTestSuite(t)
 	defer cleanup()
 
@@ -213,14 +204,12 @@ func TestIssues(t *testing.T) {
 }
 
 func TestDBNameEscape(t *testing.T) {
-	t.Parallel()
 	ts, cleanup := createTidbTestSuite(t)
 	defer cleanup()
 	ts.runTestDBNameEscape(t)
 }
 
 func TestResultFieldTableIsNull(t *testing.T) {
-	t.Parallel()
 	ts, cleanup := createTidbTestSuite(t)
 	defer cleanup()
 
@@ -228,7 +217,6 @@ func TestResultFieldTableIsNull(t *testing.T) {
 }
 
 func TestStatusAPI(t *testing.T) {
-	t.Parallel()
 	ts, cleanup := createTidbTestSuite(t)
 	defer cleanup()
 
@@ -236,7 +224,6 @@ func TestStatusAPI(t *testing.T) {
 }
 
 func TestStatusPort(t *testing.T) {
-	t.Parallel()
 	ts, cleanup := createTidbTestSuite(t)
 	defer cleanup()
 
@@ -252,7 +239,6 @@ func TestStatusPort(t *testing.T) {
 }
 
 func TestStatusAPIWithTLS(t *testing.T) {
-	t.Parallel()
 	ts, cleanup := createTidbTestSuite(t)
 	defer cleanup()
 
@@ -298,7 +284,6 @@ func TestStatusAPIWithTLS(t *testing.T) {
 }
 
 func TestStatusAPIWithTLSCNCheck(t *testing.T) {
-	t.Parallel()
 	ts, cleanup := createTidbTestSuite(t)
 	defer cleanup()
 
@@ -377,7 +362,6 @@ func newTLSHttpClient(t *testing.T, caFile, certFile, keyFile string) *http.Clie
 }
 
 func TestMultiStatements(t *testing.T) {
-	t.Parallel()
 	ts, cleanup := createTidbTestSuite(t)
 	defer cleanup()
 
@@ -386,7 +370,6 @@ func TestMultiStatements(t *testing.T) {
 }
 
 func TestSocketForwarding(t *testing.T) {
-	t.Parallel()
 	osTempDir := os.TempDir()
 	tempDir, err := os.MkdirTemp(osTempDir, "tidb-test.*.socket")
 	require.NoError(t, err)
@@ -423,7 +406,6 @@ func TestSocketForwarding(t *testing.T) {
 }
 
 func TestSocket(t *testing.T) {
-	t.Parallel()
 	osTempDir := os.TempDir()
 	tempDir, err := os.MkdirTemp(osTempDir, "tidb-test.*.socket")
 	require.NoError(t, err)
@@ -463,7 +445,6 @@ func TestSocket(t *testing.T) {
 }
 
 func TestSocketAndIp(t *testing.T) {
-	t.Parallel()
 	osTempDir := os.TempDir()
 	tempDir, err := os.MkdirTemp(osTempDir, "tidb-test.*.socket")
 	require.NoError(t, err)
@@ -633,7 +614,6 @@ func TestSocketAndIp(t *testing.T) {
 
 // TestOnlySocket for server configuration without network interface for mysql clients
 func TestOnlySocket(t *testing.T) {
-	t.Parallel()
 	osTempDir := os.TempDir()
 	tempDir, err := os.MkdirTemp(osTempDir, "tidb-test.*.socket")
 	require.NoError(t, err)
@@ -895,7 +875,6 @@ func registerTLSConfig(configName string, caCertPath string, clientCertPath stri
 }
 
 func TestSystemTimeZone(t *testing.T) {
-	t.Parallel()
 	ts, cleanup := createTidbTestSuite(t)
 	defer cleanup()
 
@@ -912,7 +891,6 @@ func TestSystemTimeZone(t *testing.T) {
 }
 
 func TestClientWithCollation(t *testing.T) {
-	t.Parallel()
 	ts, cleanup := createTidbTestSuite(t)
 	defer cleanup()
 
@@ -920,7 +898,6 @@ func TestClientWithCollation(t *testing.T) {
 }
 
 func TestCreateTableFlen(t *testing.T) {
-	t.Parallel()
 	ts, cleanup := createTidbTestSuite(t)
 	defer cleanup()
 
@@ -994,7 +971,6 @@ func Execute(ctx context.Context, qc *TiDBContext, sql string) (ResultSet, error
 }
 
 func TestShowTablesFlen(t *testing.T) {
-	t.Parallel()
 	ts, cleanup := createTidbTestSuite(t)
 	defer cleanup()
 
@@ -1026,7 +1002,6 @@ func checkColNames(t *testing.T, columns []*ColumnInfo, names ...string) {
 }
 
 func TestFieldList(t *testing.T) {
-	t.Parallel()
 	ts, cleanup := createTidbTestSuite(t)
 	defer cleanup()
 
@@ -1109,28 +1084,24 @@ func TestFieldList(t *testing.T) {
 }
 
 func TestClientErrors(t *testing.T) {
-	t.Parallel()
 	ts, cleanup := createTidbTestSuite(t)
 	defer cleanup()
 	ts.runTestInfoschemaClientErrors(t)
 }
 
 func TestInitConnect(t *testing.T) {
-	t.Parallel()
 	ts, cleanup := createTidbTestSuite(t)
 	defer cleanup()
 	ts.runTestInitConnect(t)
 }
 
 func TestSumAvg(t *testing.T) {
-	t.Parallel()
 	ts, cleanup := createTidbTestSuite(t)
 	defer cleanup()
 	ts.runTestSumAvg(t)
 }
 
 func TestNullFlag(t *testing.T) {
-	t.Parallel()
 	ts, cleanup := createTidbTestSuite(t)
 	defer cleanup()
 
@@ -1199,7 +1170,6 @@ func TestNullFlag(t *testing.T) {
 }
 
 func TestNO_DEFAULT_VALUEFlag(t *testing.T) {
-	t.Parallel()
 	ts, cleanup := createTidbTestSuite(t)
 	defer cleanup()
 
@@ -1223,7 +1193,6 @@ func TestNO_DEFAULT_VALUEFlag(t *testing.T) {
 }
 
 func TestGracefulShutdown(t *testing.T) {
-	t.Parallel()
 	ts, cleanup := createTidbTestSuite(t)
 	defer cleanup()
 
@@ -1265,7 +1234,6 @@ func TestGracefulShutdown(t *testing.T) {
 }
 
 func TestPessimisticInsertSelectForUpdate(t *testing.T) {
-	t.Parallel()
 	ts, cleanup := createTidbTestSuite(t)
 	defer cleanup()
 
@@ -1568,7 +1536,7 @@ func TestTopSQLAgent(t *testing.T) {
 	dbt.MustExec("set @@global.tidb_top_sql_report_interval_seconds=2;")
 	dbt.MustExec("set @@global.tidb_top_sql_max_statement_count=5;")
 
-	r := reporter.NewRemoteTopSQLReporter(reporter.NewGRPCReportClient(plancodec.DecodeNormalizedPlan))
+	r := reporter.NewRemoteTopSQLReporter(reporter.NewSingleTargetDataSink(plancodec.DecodeNormalizedPlan))
 	tracecpu.GlobalSQLCPUProfiler.SetCollector(&collectorWrapper{r})
 
 	// TODO: change to ensure that the right sql statements are reported, not just counts
@@ -1692,7 +1660,6 @@ func (ts *tidbTestTopSQLSuite) loopExec(ctx context.Context, t *testing.T, fn fu
 }
 
 func TestLocalhostClientMapping(t *testing.T) {
-	t.Parallel()
 	osTempDir := os.TempDir()
 	tempDir, err := os.MkdirTemp(osTempDir, "tidb-test.*.socket")
 	require.NoError(t, err)
diff --git a/server/util.go b/server/util.go
index 2a45dce017dc2..f5518f0396a9a 100644
--- a/server/util.go
+++ b/server/util.go
@@ -179,16 +179,16 @@ func dumpBinaryTime(dur time.Duration) (data []byte) {
 		dur = -dur
 	}
 	days := dur / (24 * time.Hour)
-	dur -= days * 24 * time.Hour
+	dur -= days * 24 * time.Hour //nolint:durationcheck
 	data[2] = byte(days)
 	hours := dur / time.Hour
-	dur -= hours * time.Hour
+	dur -= hours * time.Hour //nolint:durationcheck
 	data[6] = byte(hours)
 	minutes := dur / time.Minute
-	dur -= minutes * time.Minute
+	dur -= minutes * time.Minute //nolint:durationcheck
 	data[7] = byte(minutes)
 	seconds := dur / time.Second
-	dur -= seconds * time.Second
+	dur -= seconds * time.Second //nolint:durationcheck
 	data[8] = byte(seconds)
 	if dur == 0 {
 		data[0] = 8
diff --git a/server/util_test.go b/server/util_test.go
index c60f00bdf4e51..889c2512eacad 100644
--- a/server/util_test.go
+++ b/server/util_test.go
@@ -31,8 +31,6 @@ import (
 )
 
 func TestDumpBinaryTime(t *testing.T) {
-	t.Parallel()
-
 	sc := &stmtctx.StatementContext{TimeZone: time.UTC}
 	parsedTime, err := types.ParseTimestamp(sc, "0000-00-00 00:00:00.000000")
 	require.NoError(t, err)
@@ -88,7 +86,6 @@ func TestDumpBinaryTime(t *testing.T) {
 }
 
 func TestResultEncoder(t *testing.T) {
-	t.Parallel()
 	// Encode bytes to utf-8.
 	d := newResultEncoder("utf-8")
 	src := []byte("test_string")
@@ -107,8 +104,6 @@ func TestResultEncoder(t *testing.T) {
 }
 
 func TestDumpTextValue(t *testing.T) {
-	t.Parallel()
-
 	columns := []*ColumnInfo{{
 		Type:    mysql.TypeLonglong,
 		Decimal: mysql.NotFixedDec,
@@ -256,8 +251,6 @@ func mustDecodeStr(t *testing.T, b []byte) string {
 }
 
 func TestAppendFormatFloat(t *testing.T) {
-	t.Parallel()
-
 	infVal, _ := strconv.ParseFloat("+Inf", 64)
 	tests := []struct {
 		fVal    float64
@@ -440,8 +433,6 @@ func TestAppendFormatFloat(t *testing.T) {
 }
 
 func TestDumpLengthEncodedInt(t *testing.T) {
-	t.Parallel()
-
 	testCases := []struct {
 		num    uint64
 		buffer []byte
@@ -470,8 +461,6 @@ func TestDumpLengthEncodedInt(t *testing.T) {
 }
 
 func TestParseLengthEncodedInt(t *testing.T) {
-	t.Parallel()
-
 	testCases := []struct {
 		buffer []byte
 		num    uint64
@@ -520,8 +509,6 @@ func TestParseLengthEncodedInt(t *testing.T) {
 }
 
 func TestDumpUint(t *testing.T) {
-	t.Parallel()
-
 	testCases := []uint64{
 		0,
 		1,
@@ -540,8 +527,6 @@ func TestDumpUint(t *testing.T) {
 }
 
 func TestParseLengthEncodedBytes(t *testing.T) {
-	t.Parallel()
-
 	buffer := []byte{'\xfb'}
 	b, isNull, n, err := parseLengthEncodedBytes(buffer)
 	require.Nil(t, b)
@@ -565,8 +550,6 @@ func TestParseLengthEncodedBytes(t *testing.T) {
 }
 
 func TestParseNullTermString(t *testing.T) {
-	t.Parallel()
-
 	for _, tc := range []struct {
 		input  string
 		str    string
diff --git a/session/clustered_index_test.go b/session/clustered_index_test.go
index 5d69c02acf076..b993bd3405a6d 100644
--- a/session/clustered_index_test.go
+++ b/session/clustered_index_test.go
@@ -34,8 +34,6 @@ func createTestKit(t *testing.T, store kv.Storage) *testkit.TestKit {
 }
 
 func TestClusteredUnionScan(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -59,8 +57,6 @@ func TestClusteredUnionScan(t *testing.T) {
 }
 
 func TestClusteredPrefixColumn(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -134,8 +130,6 @@ func TestClusteredPrefixColumn(t *testing.T) {
 }
 
 func TestClusteredUnionScanIndexLookup(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -155,8 +149,6 @@ func TestClusteredUnionScanIndexLookup(t *testing.T) {
 }
 
 func TestClusteredIndexLookUp(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -169,8 +161,6 @@ func TestClusteredIndexLookUp(t *testing.T) {
 }
 
 func TestClusteredIndexLookUp2(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -197,8 +187,6 @@ SELECT c_balance, c_first, c_middle, c_id FROM c3 use index (idx) WHERE c_w_id =
 }
 
 func TestClusteredTopN(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -219,8 +207,6 @@ func TestClusteredTopN(t *testing.T) {
 }
 
 func TestClusteredHint(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -231,8 +217,6 @@ func TestClusteredHint(t *testing.T) {
 }
 
 func TestClusteredBatchPointGet(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -249,8 +233,6 @@ type SnapCacheSizeGetter interface {
 }
 
 func TestClusteredInsertIgnoreBatchGetKeyCount(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -270,8 +252,6 @@ func TestClusteredInsertIgnoreBatchGetKeyCount(t *testing.T) {
 }
 
 func TestClusteredPrefixingPrimaryKey(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -350,8 +330,6 @@ func TestClusteredPrefixingPrimaryKey(t *testing.T) {
 }
 
 func TestClusteredWithOldRowFormat(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -405,8 +383,6 @@ func TestClusteredWithOldRowFormat(t *testing.T) {
 }
 
 func TestIssue20002(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -423,8 +399,6 @@ func TestIssue20002(t *testing.T) {
 
 // https://github.com/pingcap/tidb/issues/20727
 func TestClusteredIndexSplitAndAddIndex(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -439,8 +413,6 @@ func TestClusteredIndexSplitAndAddIndex(t *testing.T) {
 }
 
 func TestClusteredIndexSelectWhereInNull(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
diff --git a/session/session.go b/session/session.go
index 8a2b61e50e6db..bfc5288a7ff4f 100644
--- a/session/session.go
+++ b/session/session.go
@@ -1549,7 +1549,8 @@ func (s *session) ExecuteStmt(ctx context.Context, stmtNode ast.StmtNode) (sqlex
 
 	failpoint.Inject("mockStmtSlow", func(val failpoint.Value) {
 		if strings.Contains(stmtNode.Text(), "/* sleep */") {
-			time.Sleep(time.Duration(val.(int)) * time.Millisecond)
+			v, _ := val.(int)
+			time.Sleep(time.Duration(v) * time.Millisecond)
 		}
 	})
 
diff --git a/session/tidb_test.go b/session/tidb_test.go
index 4c854b4b66354..661a8f19d5f47 100644
--- a/session/tidb_test.go
+++ b/session/tidb_test.go
@@ -27,8 +27,6 @@ import (
 )
 
 func TestSysSessionPoolGoroutineLeak(t *testing.T) {
-	t.Parallel()
-
 	store, dom := createStoreAndBootstrap(t)
 	defer func() { require.NoError(t, store.Close()) }()
 	defer dom.Close()
@@ -58,8 +56,6 @@ func TestSysSessionPoolGoroutineLeak(t *testing.T) {
 }
 
 func TestParseErrorWarn(t *testing.T) {
-	t.Parallel()
-
 	ctx := core.MockContext()
 
 	nodes, err := Parse(ctx, "select /*+ adf */ 1")
@@ -72,8 +68,6 @@ func TestParseErrorWarn(t *testing.T) {
 }
 
 func TestKeysNeedLock(t *testing.T) {
-	t.Parallel()
-
 	rowKey := tablecodec.EncodeRowKeyWithHandle(1, kv.IntHandle(1))
 	indexKey := tablecodec.EncodeIndexSeekKey(1, 1, []byte{1})
 	uniqueValue := make([]byte, 8)
diff --git a/sessionctx/variable/session_test.go b/sessionctx/variable/session_test.go
index 2d122d26dfb98..abcf79ca49158 100644
--- a/sessionctx/variable/session_test.go
+++ b/sessionctx/variable/session_test.go
@@ -61,7 +61,6 @@ func TestSetSystemVariable(t *testing.T) {
 		// copy iterator variable into a new variable, see issue #27779
 		tc := tc
 		t.Run(tc.key, func(t *testing.T) {
-			t.Parallel()
 			mtx.Lock()
 			err := variable.SetSessionSystemVar(v, tc.key, tc.value)
 			mtx.Unlock()
diff --git a/sessionctx/variable/sysvar.go b/sessionctx/variable/sysvar.go
index ebd1eed637ddd..60543c00d334e 100644
--- a/sessionctx/variable/sysvar.go
+++ b/sessionctx/variable/sysvar.go
@@ -1205,7 +1205,11 @@ var defaultSysVars = []*SysVar{
 	{Scope: ScopeSession, Name: PluginDir, Value: "/data/deploy/plugin", GetSession: func(s *SessionVars) (string, error) {
 		return config.GetGlobalConfig().Plugin.Dir, nil
 	}},
-
+	{Scope: ScopeGlobal, Name: TiDBEnableHistoricalStats, Value: Off, Type: TypeBool, GetGlobal: func(s *SessionVars) (string, error) {
+		return getTiDBTableValue(s, "tidb_enable_historical_stats", Off)
+	}, SetGlobal: func(s *SessionVars, val string) error {
+		return setTiDBTableValue(s, "tidb_enable_historical_stats", val, "Current historical statistics enable status")
+	}},
 	/* tikv gc metrics */
 	{Scope: ScopeGlobal, Name: TiDBGCEnable, Value: On, Type: TypeBool, GetGlobal: func(s *SessionVars) (string, error) {
 		return getTiDBTableValue(s, "tikv_gc_enable", On)
diff --git a/sessionctx/variable/tidb_vars.go b/sessionctx/variable/tidb_vars.go
index 518b88e45de80..ee01348a76441 100644
--- a/sessionctx/variable/tidb_vars.go
+++ b/sessionctx/variable/tidb_vars.go
@@ -620,6 +620,8 @@ const (
 	TiDBGCScanLockMode = "tidb_gc_scan_lock_mode"
 	// TiDBEnableEnhancedSecurity restricts SUPER users from certain operations.
 	TiDBEnableEnhancedSecurity = "tidb_enable_enhanced_security"
+	// TiDBEnableHistoricalStats enables the historical statistics feature (default off)
+	TiDBEnableHistoricalStats = "tidb_enable_historical_stats"
 )
 
 // TiDB intentional limits
diff --git a/sessionctx/variable/varsutil_test.go b/sessionctx/variable/varsutil_test.go
index e746d1407b305..b50399cf851a8 100644
--- a/sessionctx/variable/varsutil_test.go
+++ b/sessionctx/variable/varsutil_test.go
@@ -593,7 +593,6 @@ func TestValidate(t *testing.T) {
 
 	for _, tc := range testCases {
 		t.Run(tc.key, func(t *testing.T) {
-			t.Parallel()
 			_, err := GetSysVar(tc.key).Validate(v, tc.value, ScopeGlobal)
 			if tc.error {
 				require.Errorf(t, err, "%v got err=%v", tc, err)
@@ -622,7 +621,6 @@ func TestValidate(t *testing.T) {
 		// copy iterator variable into a new variable, see issue #27779
 		tc := tc
 		t.Run(tc.key, func(t *testing.T) {
-			t.Parallel()
 			_, err := GetSysVar(tc.key).Validate(v, tc.value, ScopeSession)
 			if tc.error {
 				require.Errorf(t, err, "%v got err=%v", tc, err)
@@ -681,7 +679,6 @@ func TestValidateStmtSummary(t *testing.T) {
 		// copy iterator variable into a new variable, see issue #27779
 		tc := tc
 		t.Run(tc.key, func(t *testing.T) {
-			t.Parallel()
 			_, err := GetSysVar(tc.key).Validate(v, tc.value, tc.scope)
 			if tc.error {
 				require.Errorf(t, err, "%v got err=%v", tc, err)
diff --git a/statistics/cmsketch_test.go b/statistics/cmsketch_test.go
index 3929fc610aed0..19400d1199aa0 100644
--- a/statistics/cmsketch_test.go
+++ b/statistics/cmsketch_test.go
@@ -107,7 +107,6 @@ func averageAbsoluteError(cms *CMSketch, topN *TopN, mp map[int64]uint32) (uint6
 }
 
 func TestCMSketch(t *testing.T) {
-	t.Parallel()
 	tests := []struct {
 		zipfFactor float64
 		avgError   uint64
@@ -152,7 +151,6 @@ func TestCMSketch(t *testing.T) {
 }
 
 func TestCMSketchCoding(t *testing.T) {
-	t.Parallel()
 	lSketch := NewCMSketch(5, 2048)
 	lSketch.count = 2048 * math.MaxUint32
 	for i := range lSketch.table {
@@ -169,7 +167,6 @@ func TestCMSketchCoding(t *testing.T) {
 }
 
 func TestCMSketchTopN(t *testing.T) {
-	t.Parallel()
 	tests := []struct {
 		zipfFactor float64
 		avgError   uint64
@@ -208,7 +205,6 @@ func TestCMSketchTopN(t *testing.T) {
 }
 
 func TestMergeCMSketch4IncrementalAnalyze(t *testing.T) {
-	t.Parallel()
 	tests := []struct {
 		zipfFactor float64
 		avgError   uint64
@@ -259,7 +255,6 @@ func TestMergeCMSketch4IncrementalAnalyze(t *testing.T) {
 }
 
 func TestCMSketchTopNUniqueData(t *testing.T) {
-	t.Parallel()
 	d, w := int32(5), int32(2048)
 	total := uint64(1000000)
 	mp := make(map[int64]uint32)
@@ -281,7 +276,6 @@ func TestCMSketchTopNUniqueData(t *testing.T) {
 }
 
 func TestCMSketchCodingTopN(t *testing.T) {
-	t.Parallel()
 	lSketch := NewCMSketch(5, 2048)
 	lSketch.count = 2048 * (math.MaxUint32)
 	for i := range lSketch.table {
diff --git a/statistics/feedback.go b/statistics/feedback.go
index 88824afae0e08..12e986f95bff5 100644
--- a/statistics/feedback.go
+++ b/statistics/feedback.go
@@ -130,6 +130,25 @@ func (m *QueryFeedbackMap) append(k QueryFeedbackKey, qs []*QueryFeedback) bool
 	return true
 }
 
+// SiftFeedbacks eliminates feedbacks which are overlapped with others. It is a tradeoff between
+// feedback accuracy and its overhead.
+func (m *QueryFeedbackMap) SiftFeedbacks() {
+	sc := &stmtctx.StatementContext{TimeZone: time.UTC}
+	for k, qs := range m.Feedbacks {
+		fbs := make([]Feedback, 0, len(qs)*2)
+		for _, q := range qs {
+			fbs = append(fbs, q.Feedback...)
+		}
+		if len(fbs) == 0 {
+			delete(m.Feedbacks, k)
+			continue
+		}
+		m.Feedbacks[k] = m.Feedbacks[k][:1]
+		m.Feedbacks[k][0].Feedback, _ = NonOverlappedFeedbacks(sc, fbs)
+	}
+	m.Size = len(m.Feedbacks)
+}
+
 // Merge combines 2 collections of feedbacks.
 func (m *QueryFeedbackMap) Merge(r *QueryFeedbackMap) {
 	for k, qs := range r.Feedbacks {
diff --git a/statistics/feedback_test.go b/statistics/feedback_test.go
index f79a8b3126084..33366f2805e7e 100644
--- a/statistics/feedback_test.go
+++ b/statistics/feedback_test.go
@@ -55,7 +55,6 @@ func genHistogram() *Histogram {
 }
 
 func TestUpdateHistogram(t *testing.T) {
-	t.Parallel()
 	feedbacks := []Feedback{
 		newFeedback(0, 1, 10000, 1),
 		newFeedback(1, 2, 1, 1),
@@ -80,7 +79,6 @@ func TestUpdateHistogram(t *testing.T) {
 }
 
 func TestSplitBuckets(t *testing.T) {
-	t.Parallel()
 	// test bucket split
 	feedbacks := []Feedback{newFeedback(0, 1, 1, 1)}
 	for i := 0; i < 100; i++ {
@@ -190,7 +188,6 @@ func TestSplitBuckets(t *testing.T) {
 }
 
 func TestMergeBuckets(t *testing.T) {
-	t.Parallel()
 	tests := []struct {
 		points       []int64
 		counts       []int64
@@ -252,7 +249,6 @@ func encodeInt(v int64) *types.Datum {
 }
 
 func TestFeedbackEncoding(t *testing.T) {
-	t.Parallel()
 	hist := NewHistogram(0, 0, 0, 0, types.NewFieldType(mysql.TypeLong), 0, 0)
 	q := &QueryFeedback{Hist: hist, Tp: PkType}
 	q.Feedback = append(q.Feedback, Feedback{encodeInt(0), encodeInt(3), 1, 0, 1})
diff --git a/statistics/fmsketch_test.go b/statistics/fmsketch_test.go
index 9bf5ec35033f7..768db16fb913d 100644
--- a/statistics/fmsketch_test.go
+++ b/statistics/fmsketch_test.go
@@ -35,7 +35,6 @@ func extractSampleItemsDatums(items []*SampleItem) []types.Datum {
 
 func SubTestSketch() func(*testing.T) {
 	return func(t *testing.T) {
-		t.Parallel()
 		s := createTestStatisticsSamples(t)
 		sc := &stmtctx.StatementContext{TimeZone: time.Local}
 		maxSize := 1000
@@ -67,7 +66,6 @@ func SubTestSketch() func(*testing.T) {
 
 func SubTestSketchProtoConversion() func(*testing.T) {
 	return func(t *testing.T) {
-		t.Parallel()
 		s := createTestStatisticsSamples(t)
 		sc := &stmtctx.StatementContext{TimeZone: time.Local}
 		maxSize := 1000
@@ -86,7 +84,6 @@ func SubTestSketchProtoConversion() func(*testing.T) {
 
 func SubTestFMSketchCoding() func(*testing.T) {
 	return func(t *testing.T) {
-		t.Parallel()
 		s := createTestStatisticsSamples(t)
 		sc := &stmtctx.StatementContext{TimeZone: time.Local}
 		maxSize := 1000
diff --git a/statistics/handle/ddl_serial_test.go b/statistics/handle/ddl_serial_test.go
index 76121694338df..91a3a244cb17d 100644
--- a/statistics/handle/ddl_serial_test.go
+++ b/statistics/handle/ddl_serial_test.go
@@ -18,10 +18,10 @@ import (
 	"testing"
 
 	"github.com/pingcap/tidb/parser/model"
-	"github.com/pingcap/tidb/sessionctx/stmtctx"
 	"github.com/pingcap/tidb/sessionctx/variable"
 	"github.com/pingcap/tidb/testkit"
 	"github.com/pingcap/tidb/types"
+	"github.com/pingcap/tidb/util/mock"
 	"github.com/stretchr/testify/require"
 )
 
@@ -51,10 +51,10 @@ func TestDDLAfterLoad(t *testing.T) {
 	require.NoError(t, err)
 	tableInfo = tbl.Meta()
 
-	sc := new(stmtctx.StatementContext)
-	count := statsTbl.ColumnGreaterRowCount(sc, types.NewDatum(recordCount+1), tableInfo.Columns[0].ID)
+	sctx := mock.NewContext()
+	count := statsTbl.ColumnGreaterRowCount(sctx, types.NewDatum(recordCount+1), tableInfo.Columns[0].ID)
 	require.Equal(t, 0.0, count)
-	count = statsTbl.ColumnGreaterRowCount(sc, types.NewDatum(recordCount+1), tableInfo.Columns[2].ID)
+	count = statsTbl.ColumnGreaterRowCount(sctx, types.NewDatum(recordCount+1), tableInfo.Columns[2].ID)
 	require.Equal(t, 333, int(count))
 }
 
@@ -131,11 +131,11 @@ func TestDDLHistogram(t *testing.T) {
 	tableInfo = tbl.Meta()
 	statsTbl = do.StatsHandle().GetTableStats(tableInfo)
 	require.False(t, statsTbl.Pseudo)
-	sc := new(stmtctx.StatementContext)
-	count, err := statsTbl.ColumnEqualRowCount(sc, types.NewIntDatum(0), tableInfo.Columns[3].ID)
+	sctx := mock.NewContext()
+	count, err := statsTbl.ColumnEqualRowCount(sctx, types.NewIntDatum(0), tableInfo.Columns[3].ID)
 	require.NoError(t, err)
 	require.Equal(t, float64(2), count)
-	count, err = statsTbl.ColumnEqualRowCount(sc, types.NewIntDatum(1), tableInfo.Columns[3].ID)
+	count, err = statsTbl.ColumnEqualRowCount(sctx, types.NewIntDatum(1), tableInfo.Columns[3].ID)
 	require.NoError(t, err)
 	require.Equal(t, float64(0), count)
 
diff --git a/statistics/handle/handle.go b/statistics/handle/handle.go
index 872cdc3daf16f..15d90c6ed5204 100644
--- a/statistics/handle/handle.go
+++ b/statistics/handle/handle.go
@@ -99,9 +99,15 @@ type Handle struct {
 	// listHead contains all the stats collector required by session.
 	listHead *SessionStatsCollector
 	// globalMap contains all the delta map from collectors when we dump them to KV.
-	globalMap tableDeltaMap
+	globalMap struct {
+		sync.Mutex
+		data tableDeltaMap
+	}
 	// feedback is used to store query feedback info.
-	feedback *statistics.QueryFeedbackMap
+	feedback struct {
+		sync.Mutex
+		data *statistics.QueryFeedbackMap
+	}
 
 	lease atomic2.Duration
 
@@ -159,6 +165,7 @@ func (h *Handle) execRestrictedSQLWithSnapshot(ctx context.Context, sql string,
 
 // Clear the statsCache, only for test.
 func (h *Handle) Clear() {
+	// TODO: Here h.mu seems to protect all the fields of Handle. Is is reasonable?
 	h.mu.Lock()
 	h.statsCache.Lock()
 	h.statsCache.Store(statsCache{tables: make(map[int64]*statistics.Table)})
@@ -167,13 +174,17 @@ func (h *Handle) Clear() {
 	for len(h.ddlEventCh) > 0 {
 		<-h.ddlEventCh
 	}
-	h.feedback = statistics.NewQueryFeedbackMap()
+	h.feedback.Lock()
+	h.feedback.data = statistics.NewQueryFeedbackMap()
+	h.feedback.Unlock()
 	h.mu.ctx.GetSessionVars().InitChunkSize = 1
 	h.mu.ctx.GetSessionVars().MaxChunkSize = 1
 	h.mu.ctx.GetSessionVars().EnableChunkRPC = false
 	h.mu.ctx.GetSessionVars().SetProjectionConcurrency(0)
 	h.listHead = &SessionStatsCollector{mapper: make(tableDeltaMap), rateMap: make(errorRateDeltaMap)}
-	h.globalMap = make(tableDeltaMap)
+	h.globalMap.Lock()
+	h.globalMap.data = make(tableDeltaMap)
+	h.globalMap.Unlock()
 	h.mu.rateMap = make(errorRateDeltaMap)
 	h.mu.Unlock()
 }
@@ -188,8 +199,6 @@ func NewHandle(ctx sessionctx.Context, lease time.Duration, pool sessionPool) (*
 	handle := &Handle{
 		ddlEventCh:       make(chan *util.Event, 100),
 		listHead:         &SessionStatsCollector{mapper: make(tableDeltaMap), rateMap: make(errorRateDeltaMap)},
-		globalMap:        make(tableDeltaMap),
-		feedback:         statistics.NewQueryFeedbackMap(),
 		idxUsageListHead: &SessionIndexUsageCollector{mapper: make(indexUsageMap)},
 		pool:             pool,
 	}
@@ -199,6 +208,8 @@ func NewHandle(ctx sessionctx.Context, lease time.Duration, pool sessionPool) (*
 	handle.mu.ctx = ctx
 	handle.mu.rateMap = make(errorRateDeltaMap)
 	handle.statsCache.Store(statsCache{tables: make(map[int64]*statistics.Table)})
+	handle.globalMap.data = make(tableDeltaMap)
+	handle.feedback.data = statistics.NewQueryFeedbackMap()
 	err := handle.RefreshVars()
 	if err != nil {
 		return nil, err
@@ -218,10 +229,12 @@ func (h *Handle) SetLease(lease time.Duration) {
 
 // GetQueryFeedback gets the query feedback. It is only used in test.
 func (h *Handle) GetQueryFeedback() *statistics.QueryFeedbackMap {
+	h.feedback.Lock()
 	defer func() {
-		h.feedback = statistics.NewQueryFeedbackMap()
+		h.feedback.data = statistics.NewQueryFeedbackMap()
+		h.feedback.Unlock()
 	}()
-	return h.feedback
+	return h.feedback.data
 }
 
 // DurationToTS converts duration to timestamp.
diff --git a/statistics/handle/handle_test.go b/statistics/handle/handle_test.go
index 23b2de4333af8..70ec989f7bca6 100644
--- a/statistics/handle/handle_test.go
+++ b/statistics/handle/handle_test.go
@@ -32,7 +32,6 @@ import (
 	"github.com/pingcap/tidb/parser/model"
 	"github.com/pingcap/tidb/parser/terror"
 	"github.com/pingcap/tidb/session"
-	"github.com/pingcap/tidb/sessionctx/stmtctx"
 	"github.com/pingcap/tidb/sessionctx/variable"
 	"github.com/pingcap/tidb/statistics"
 	"github.com/pingcap/tidb/statistics/handle"
@@ -40,6 +39,7 @@ import (
 	"github.com/pingcap/tidb/types"
 	"github.com/pingcap/tidb/util/collate"
 	"github.com/pingcap/tidb/util/israce"
+	"github.com/pingcap/tidb/util/mock"
 	"github.com/pingcap/tidb/util/ranger"
 	"github.com/pingcap/tidb/util/testkit"
 	"github.com/tikv/client-go/v2/oracle"
@@ -267,8 +267,7 @@ func (s *testStatsSuite) TestEmptyTable(c *C) {
 	c.Assert(err, IsNil)
 	tableInfo := tbl.Meta()
 	statsTbl := do.StatsHandle().GetTableStats(tableInfo)
-	sc := new(stmtctx.StatementContext)
-	count := statsTbl.ColumnGreaterRowCount(sc, types.NewDatum(1), tableInfo.Columns[0].ID)
+	count := statsTbl.ColumnGreaterRowCount(mock.NewContext(), types.NewDatum(1), tableInfo.Columns[0].ID)
 	c.Assert(count, Equals, 0.0)
 }
 
@@ -285,14 +284,14 @@ func (s *testStatsSuite) TestColumnIDs(c *C) {
 	c.Assert(err, IsNil)
 	tableInfo := tbl.Meta()
 	statsTbl := do.StatsHandle().GetTableStats(tableInfo)
-	sc := new(stmtctx.StatementContext)
+	sctx := mock.NewContext()
 	ran := &ranger.Range{
 		LowVal:      []types.Datum{types.MinNotNullDatum()},
 		HighVal:     []types.Datum{types.NewIntDatum(2)},
 		LowExclude:  false,
 		HighExclude: true,
 	}
-	count, err := statsTbl.GetRowCountByColumnRanges(sc, tableInfo.Columns[0].ID, []*ranger.Range{ran})
+	count, err := statsTbl.GetRowCountByColumnRanges(sctx, tableInfo.Columns[0].ID, []*ranger.Range{ran})
 	c.Assert(err, IsNil)
 	c.Assert(count, Equals, float64(1))
 
@@ -307,7 +306,7 @@ func (s *testStatsSuite) TestColumnIDs(c *C) {
 	tableInfo = tbl.Meta()
 	statsTbl = do.StatsHandle().GetTableStats(tableInfo)
 	// At that time, we should get c2's stats instead of c1's.
-	count, err = statsTbl.GetRowCountByColumnRanges(sc, tableInfo.Columns[0].ID, []*ranger.Range{ran})
+	count, err = statsTbl.GetRowCountByColumnRanges(sctx, tableInfo.Columns[0].ID, []*ranger.Range{ran})
 	c.Assert(err, IsNil)
 	c.Assert(count, Equals, 0.0)
 }
@@ -614,7 +613,7 @@ func (s *testStatsSuite) TestLoadStats(c *C) {
 	c.Assert(hg.Len(), Equals, 0)
 	cms = stat.Columns[tableInfo.Columns[2].ID].CMSketch
 	c.Assert(cms, IsNil)
-	_, err = stat.ColumnEqualRowCount(testKit.Se.GetSessionVars().StmtCtx, types.NewIntDatum(1), tableInfo.Columns[2].ID)
+	_, err = stat.ColumnEqualRowCount(testKit.Se, types.NewIntDatum(1), tableInfo.Columns[2].ID)
 	c.Assert(err, IsNil)
 	c.Assert(h.LoadNeededHistograms(), IsNil)
 	stat = h.GetTableStats(tableInfo)
diff --git a/statistics/handle/update.go b/statistics/handle/update.go
index e8672794a2509..a36f12bbdd7d2 100644
--- a/statistics/handle/update.go
+++ b/statistics/handle/update.go
@@ -32,6 +32,7 @@ import (
 	"github.com/pingcap/tidb/parser/model"
 	"github.com/pingcap/tidb/parser/mysql"
 	"github.com/pingcap/tidb/parser/terror"
+	"github.com/pingcap/tidb/sessionctx"
 	"github.com/pingcap/tidb/sessionctx/stmtctx"
 	"github.com/pingcap/tidb/sessionctx/variable"
 	"github.com/pingcap/tidb/statistics"
@@ -64,6 +65,12 @@ func (m tableDeltaMap) update(id int64, delta int64, count int64, colSize *map[i
 	m[id] = item
 }
 
+func (m tableDeltaMap) merge(deltaMap tableDeltaMap) {
+	for id, item := range deltaMap {
+		m.update(id, item.Delta, item.Count, &item.ColSize)
+	}
+}
+
 type errorRateDelta struct {
 	PkID         int64
 	PkErrorRate  *statistics.ErrorRate
@@ -125,14 +132,12 @@ func (m errorRateDeltaMap) clear(tableID int64, histID int64, isIndex bool) {
 	m[tableID] = item
 }
 
-func (h *Handle) merge(s *SessionStatsCollector, rateMap errorRateDeltaMap) {
-	for id, item := range s.mapper {
-		h.globalMap.update(id, item.Delta, item.Count, &item.ColSize)
-	}
+func merge(s *SessionStatsCollector, deltaMap tableDeltaMap, rateMap errorRateDeltaMap, feedback *statistics.QueryFeedbackMap) {
+	deltaMap.merge(s.mapper)
 	s.mapper = make(tableDeltaMap)
 	rateMap.merge(s.rateMap)
 	s.rateMap = make(errorRateDeltaMap)
-	h.feedback.Merge(s.feedback)
+	feedback.Merge(s.feedback)
 	s.feedback = statistics.NewQueryFeedbackMap()
 }
 
@@ -375,13 +380,15 @@ const (
 // sweepList will loop over the list, merge each session's local stats into handle
 // and remove closed session's collector.
 func (h *Handle) sweepList() {
+	deltaMap := make(tableDeltaMap)
+	errorRateMap := make(errorRateDeltaMap)
+	feedback := statistics.NewQueryFeedbackMap()
 	prev := h.listHead
 	prev.Lock()
-	errorRateMap := make(errorRateDeltaMap)
 	for curr := prev.next; curr != nil; curr = curr.next {
 		curr.Lock()
-		// Merge the session stats into handle and error rate map.
-		h.merge(curr, errorRateMap)
+		// Merge the session stats into deltaMap, errorRateMap and feedback respectively.
+		merge(curr, deltaMap, errorRateMap, feedback)
 		if curr.deleted {
 			prev.next = curr.next
 			// Since the session is already closed, we can safely unlock it here.
@@ -393,37 +400,34 @@ func (h *Handle) sweepList() {
 		}
 	}
 	prev.Unlock()
+	h.globalMap.Lock()
+	h.globalMap.data.merge(deltaMap)
+	h.globalMap.Unlock()
 	h.mu.Lock()
 	h.mu.rateMap.merge(errorRateMap)
 	h.mu.Unlock()
-	h.siftFeedbacks()
-}
-
-// siftFeedbacks eliminates feedbacks which are overlapped with others. It is a tradeoff between
-// feedback accuracy and its overhead.
-func (h *Handle) siftFeedbacks() {
-	sc := &stmtctx.StatementContext{TimeZone: time.UTC}
-	for k, qs := range h.feedback.Feedbacks {
-		fbs := make([]statistics.Feedback, 0, len(qs)*2)
-		for _, q := range qs {
-			fbs = append(fbs, q.Feedback...)
-		}
-		if len(fbs) == 0 {
-			delete(h.feedback.Feedbacks, k)
-			continue
-		}
-		h.feedback.Feedbacks[k] = h.feedback.Feedbacks[k][:1]
-		h.feedback.Feedbacks[k][0].Feedback, _ = statistics.NonOverlappedFeedbacks(sc, fbs)
-	}
-	h.feedback.Size = len(h.feedback.Feedbacks)
+	h.feedback.Lock()
+	h.feedback.data.Merge(feedback)
+	h.feedback.data.SiftFeedbacks()
+	h.feedback.Unlock()
 }
 
 // DumpStatsDeltaToKV sweeps the whole list and updates the global map, then we dumps every table that held in map to KV.
 // If the mode is `DumpDelta`, it will only dump that delta info that `Modify Count / Table Count` greater than a ratio.
 func (h *Handle) DumpStatsDeltaToKV(mode dumpMode) error {
 	h.sweepList()
+	h.globalMap.Lock()
+	deltaMap := h.globalMap.data
+	h.globalMap.data = make(tableDeltaMap)
+	h.globalMap.Unlock()
+	defer func() {
+		h.globalMap.Lock()
+		deltaMap.merge(h.globalMap.data)
+		h.globalMap.data = deltaMap
+		h.globalMap.Unlock()
+	}()
 	currentTime := time.Now()
-	for id, item := range h.globalMap {
+	for id, item := range deltaMap {
 		if mode == DumpDelta && !needDumpStatsDelta(h, id, item, currentTime) {
 			continue
 		}
@@ -432,17 +436,17 @@ func (h *Handle) DumpStatsDeltaToKV(mode dumpMode) error {
 			return errors.Trace(err)
 		}
 		if updated {
-			h.globalMap.update(id, -item.Delta, -item.Count, nil)
+			deltaMap.update(id, -item.Delta, -item.Count, nil)
 		}
 		if err = h.dumpTableStatColSizeToKV(id, item); err != nil {
 			return errors.Trace(err)
 		}
 		if updated {
-			delete(h.globalMap, id)
+			delete(deltaMap, id)
 		} else {
-			m := h.globalMap[id]
+			m := deltaMap[id]
 			m.ColSize = nil
-			h.globalMap[id] = m
+			deltaMap[id] = m
 		}
 	}
 	return nil
@@ -522,8 +526,12 @@ func (h *Handle) dumpTableStatColSizeToKV(id int64, delta variable.TableDelta) e
 
 // DumpStatsFeedbackToKV dumps the stats feedback to KV.
 func (h *Handle) DumpStatsFeedbackToKV() error {
+	h.feedback.Lock()
+	feedback := h.feedback.data
+	h.feedback.data = statistics.NewQueryFeedbackMap()
+	h.feedback.Unlock()
 	var err error
-	for _, fbs := range h.feedback.Feedbacks {
+	for _, fbs := range feedback.Feedbacks {
 		for _, fb := range fbs {
 			if fb.Tp == statistics.PkType {
 				err = h.DumpFeedbackToKV(fb)
@@ -548,7 +556,6 @@ func (h *Handle) DumpStatsFeedbackToKV() error {
 			}
 		}
 	}
-	h.feedback = statistics.NewQueryFeedbackMap()
 	return errors.Trace(err)
 }
 
@@ -581,8 +588,12 @@ func (h *Handle) DumpFeedbackToKV(fb *statistics.QueryFeedback) error {
 // feedback locally on this tidb-server, so it could be used more timely.
 func (h *Handle) UpdateStatsByLocalFeedback(is infoschema.InfoSchema) {
 	h.sweepList()
+	h.feedback.Lock()
+	feedback := h.feedback.data
+	h.feedback.data = statistics.NewQueryFeedbackMap()
+	h.feedback.Unlock()
 OUTER:
-	for _, fbs := range h.feedback.Feedbacks {
+	for _, fbs := range feedback.Feedbacks {
 		for _, fb := range fbs {
 			h.mu.Lock()
 			table, ok := h.getTableByPhysicalID(is, fb.PhysicalID)
@@ -1256,7 +1267,18 @@ func (h *Handle) RecalculateExpectCount(q *statistics.QueryFeedback) error {
 		return nil
 	}
 
-	sc := &stmtctx.StatementContext{TimeZone: time.UTC}
+	se, err := h.pool.Get()
+	if err != nil {
+		return err
+	}
+	sctx := se.(sessionctx.Context)
+	timeZone := sctx.GetSessionVars().StmtCtx.TimeZone
+	defer func() {
+		sctx.GetSessionVars().StmtCtx.TimeZone = timeZone
+		h.pool.Put(se)
+	}()
+	sctx.GetSessionVars().StmtCtx.TimeZone = time.UTC
+
 	ranges, err := q.DecodeToRanges(isIndex)
 	if err != nil {
 		return errors.Trace(err)
@@ -1264,10 +1286,10 @@ func (h *Handle) RecalculateExpectCount(q *statistics.QueryFeedback) error {
 	expected := 0.0
 	if isIndex {
 		idx := t.Indices[id]
-		expected, err = idx.GetRowCount(sc, nil, ranges, t.Count)
+		expected, err = idx.GetRowCount(sctx, nil, ranges, t.Count)
 	} else {
 		c := t.Columns[id]
-		expected, err = c.GetColumnRowCount(sc, ranges, t.Count, true)
+		expected, err = c.GetColumnRowCount(sctx, ranges, t.Count, true)
 	}
 	q.Expected = int64(expected)
 	return err
@@ -1344,7 +1366,20 @@ func (h *Handle) DumpFeedbackForIndex(q *statistics.QueryFeedback, t *statistics
 	if !ok {
 		return nil
 	}
-	sc := &stmtctx.StatementContext{TimeZone: time.UTC}
+
+	se, err := h.pool.Get()
+	if err != nil {
+		return err
+	}
+	sctx := se.(sessionctx.Context)
+	sc := sctx.GetSessionVars().StmtCtx
+	timeZone := sc.TimeZone
+	defer func() {
+		sctx.GetSessionVars().StmtCtx.TimeZone = timeZone
+		h.pool.Put(se)
+	}()
+	sc.TimeZone = time.UTC
+
 	if idx.CMSketch == nil || idx.StatsVer < statistics.Version1 {
 		return h.DumpFeedbackToKV(q)
 	}
@@ -1359,7 +1394,6 @@ func (h *Handle) DumpFeedbackForIndex(q *statistics.QueryFeedback, t *statistics
 		if rangePosition == 0 || rangePosition == len(ran.LowVal) {
 			continue
 		}
-
 		bytes, err := codec.EncodeKey(sc, nil, ran.LowVal[:rangePosition]...)
 		if err != nil {
 			logutil.BgLogger().Debug("encode keys fail", zap.Error(err))
@@ -1375,12 +1409,12 @@ func (h *Handle) DumpFeedbackForIndex(q *statistics.QueryFeedback, t *statistics
 		rangeFB := &statistics.QueryFeedback{PhysicalID: q.PhysicalID}
 		// prefer index stats over column stats
 		if idx := t.IndexStartWithColumn(colName); idx != nil && idx.Histogram.Len() != 0 {
-			rangeCount, err = t.GetRowCountByIndexRanges(sc, idx.ID, []*ranger.Range{rang})
+			rangeCount, err = t.GetRowCountByIndexRanges(sctx, idx.ID, []*ranger.Range{rang})
 			rangeFB.Tp, rangeFB.Hist = statistics.IndexType, &idx.Histogram
 		} else if col := t.ColumnByName(colName); col != nil && col.Histogram.Len() != 0 {
 			err = convertRangeType(rang, col.Tp, time.UTC)
 			if err == nil {
-				rangeCount, err = t.GetRowCountByColumnRanges(sc, col.ID, []*ranger.Range{rang})
+				rangeCount, err = t.GetRowCountByColumnRanges(sctx, col.ID, []*ranger.Range{rang})
 				rangeFB.Tp, rangeFB.Hist = statistics.ColType, &col.Histogram
 			}
 		} else {
diff --git a/statistics/handle/update_list_test.go b/statistics/handle/update_list_test.go
index 8c67c4fa0a8d4..cbedae29c9bc3 100644
--- a/statistics/handle/update_list_test.go
+++ b/statistics/handle/update_list_test.go
@@ -22,11 +22,10 @@ import (
 )
 
 func TestInsertAndDelete(t *testing.T) {
-	t.Parallel()
 	h := Handle{
 		listHead: &SessionStatsCollector{mapper: make(tableDeltaMap)},
-		feedback: statistics.NewQueryFeedbackMap(),
 	}
+	h.feedback.data = statistics.NewQueryFeedbackMap()
 	var items []*SessionStatsCollector
 	for i := 0; i < 5; i++ {
 		items = append(items, h.NewSessionStatsCollector())
diff --git a/statistics/handle/update_test.go b/statistics/handle/update_test.go
index fe4904e254be5..3d41f92701593 100644
--- a/statistics/handle/update_test.go
+++ b/statistics/handle/update_test.go
@@ -149,7 +149,7 @@ func (s *testStatsSuite) TestSingleSessionInsert(c *C) {
 	c.Assert(stats1.Count, Equals, int64(rowCount1*2))
 
 	// Test IncreaseFactor.
-	count, err := stats1.ColumnEqualRowCount(testKit.Se.GetSessionVars().StmtCtx, types.NewIntDatum(1), tableInfo1.Columns[0].ID)
+	count, err := stats1.ColumnEqualRowCount(testKit.Se, types.NewIntDatum(1), tableInfo1.Columns[0].ID)
 	c.Assert(err, IsNil)
 	c.Assert(count, Equals, float64(rowCount1*2))
 
diff --git a/statistics/histogram.go b/statistics/histogram.go
index a61f1d1405f59..5e1788da7a1ac 100644
--- a/statistics/histogram.go
+++ b/statistics/histogram.go
@@ -30,6 +30,7 @@ import (
 	"github.com/pingcap/tidb/parser/model"
 	"github.com/pingcap/tidb/parser/mysql"
 	"github.com/pingcap/tidb/parser/terror"
+	"github.com/pingcap/tidb/sessionctx"
 	"github.com/pingcap/tidb/sessionctx/stmtctx"
 	"github.com/pingcap/tidb/sessionctx/variable"
 	"github.com/pingcap/tidb/tablecodec"
@@ -506,7 +507,7 @@ func (hg *Histogram) BetweenRowCount(a, b types.Datum) float64 {
 }
 
 // BetweenRowCount estimates the row count for interval [l, r).
-func (c *Column) BetweenRowCount(sc *stmtctx.StatementContext, l, r types.Datum, lowEncoded, highEncoded []byte) float64 {
+func (c *Column) BetweenRowCount(sctx sessionctx.Context, l, r types.Datum, lowEncoded, highEncoded []byte) float64 {
 	histBetweenCnt := c.Histogram.BetweenRowCount(l, r)
 	if c.StatsVer <= Version1 {
 		return histBetweenCnt
@@ -1067,17 +1068,17 @@ var HistogramNeededColumns = neededColumnMap{cols: map[tableColumnID]struct{}{}}
 
 // IsInvalid checks if this column is invalid. If this column has histogram but not loaded yet, then we mark it
 // as need histogram.
-func (c *Column) IsInvalid(sc *stmtctx.StatementContext, collPseudo bool) bool {
+func (c *Column) IsInvalid(sctx sessionctx.Context, collPseudo bool) bool {
 	if collPseudo && c.NotAccurate() {
 		return true
 	}
-	if c.Histogram.NDV > 0 && c.notNullCount() == 0 && sc != nil {
+	if c.Histogram.NDV > 0 && c.notNullCount() == 0 && sctx != nil && sctx.GetSessionVars().StmtCtx != nil {
 		HistogramNeededColumns.insert(tableColumnID{TableID: c.PhysicalID, ColumnID: c.Info.ID})
 	}
 	return c.TotalRowCount() == 0 || (c.Histogram.NDV > 0 && c.notNullCount() == 0)
 }
 
-func (c *Column) equalRowCount(sc *stmtctx.StatementContext, val types.Datum, encodedVal []byte, realtimeRowCount int64) (float64, error) {
+func (c *Column) equalRowCount(sctx sessionctx.Context, val types.Datum, encodedVal []byte, realtimeRowCount int64) (float64, error) {
 	if val.IsNull() {
 		return float64(c.NullCount), nil
 	}
@@ -1090,7 +1091,7 @@ func (c *Column) equalRowCount(sc *stmtctx.StatementContext, val types.Datum, en
 			return outOfRangeEQSelectivity(c.Histogram.NDV, realtimeRowCount, int64(c.TotalRowCount())) * c.TotalRowCount(), nil
 		}
 		if c.CMSketch != nil {
-			count, err := queryValue(sc, c.CMSketch, c.TopN, val)
+			count, err := queryValue(sctx.GetSessionVars().StmtCtx, c.CMSketch, c.TopN, val)
 			return float64(count), errors.Trace(err)
 		}
 		histRowCount, _ := c.Histogram.equalRowCount(val, false)
@@ -1123,7 +1124,8 @@ func (c *Column) equalRowCount(sc *stmtctx.StatementContext, val types.Datum, en
 }
 
 // GetColumnRowCount estimates the row count by a slice of Range.
-func (c *Column) GetColumnRowCount(sc *stmtctx.StatementContext, ranges []*ranger.Range, realtimeRowCount int64, pkIsHandle bool) (float64, error) {
+func (c *Column) GetColumnRowCount(sctx sessionctx.Context, ranges []*ranger.Range, realtimeRowCount int64, pkIsHandle bool) (float64, error) {
+	sc := sctx.GetSessionVars().StmtCtx
 	var rowCount float64
 	for _, rg := range ranges {
 		highVal := *rg.HighVal[0].Clone()
@@ -1155,7 +1157,7 @@ func (c *Column) GetColumnRowCount(sc *stmtctx.StatementContext, ranges []*range
 					continue
 				}
 				var cnt float64
-				cnt, err = c.equalRowCount(sc, lowVal, lowEncoded, realtimeRowCount)
+				cnt, err = c.equalRowCount(sctx, lowVal, lowEncoded, realtimeRowCount)
 				if err != nil {
 					return 0, errors.Trace(err)
 				}
@@ -1173,7 +1175,7 @@ func (c *Column) GetColumnRowCount(sc *stmtctx.StatementContext, ranges []*range
 			// case 2: it's a small range && using ver1 stats
 			if rangeVals != nil {
 				for _, val := range rangeVals {
-					cnt, err := c.equalRowCount(sc, val, lowEncoded, realtimeRowCount)
+					cnt, err := c.equalRowCount(sctx, val, lowEncoded, realtimeRowCount)
 					if err != nil {
 						return 0, err
 					}
@@ -1187,12 +1189,12 @@ func (c *Column) GetColumnRowCount(sc *stmtctx.StatementContext, ranges []*range
 		}
 
 		// case 3: it's an interval
-		cnt := c.BetweenRowCount(sc, lowVal, highVal, lowEncoded, highEncoded)
+		cnt := c.BetweenRowCount(sctx, lowVal, highVal, lowEncoded, highEncoded)
 		// `betweenRowCount` returns count for [l, h) range, we adjust cnt for boundaries here.
 		// Note that, `cnt` does not include null values, we need specially handle cases
 		// where null is the lower bound.
 		if rg.LowExclude && !lowVal.IsNull() {
-			lowCnt, err := c.equalRowCount(sc, lowVal, lowEncoded, realtimeRowCount)
+			lowCnt, err := c.equalRowCount(sctx, lowVal, lowEncoded, realtimeRowCount)
 			if err != nil {
 				return 0, errors.Trace(err)
 			}
@@ -1202,7 +1204,7 @@ func (c *Column) GetColumnRowCount(sc *stmtctx.StatementContext, ranges []*range
 			cnt += float64(c.NullCount)
 		}
 		if !rg.HighExclude {
-			highCnt, err := c.equalRowCount(sc, highVal, highEncoded, realtimeRowCount)
+			highCnt, err := c.equalRowCount(sctx, highVal, highEncoded, realtimeRowCount)
 			if err != nil {
 				return 0, errors.Trace(err)
 			}
@@ -1326,7 +1328,8 @@ func (idx *Index) QueryBytes(d []byte) uint64 {
 
 // GetRowCount returns the row count of the given ranges.
 // It uses the modifyCount to adjust the influence of modifications on the table.
-func (idx *Index) GetRowCount(sc *stmtctx.StatementContext, coll *HistColl, indexRanges []*ranger.Range, realtimeRowCount int64) (float64, error) {
+func (idx *Index) GetRowCount(sctx sessionctx.Context, coll *HistColl, indexRanges []*ranger.Range, realtimeRowCount int64) (float64, error) {
+	sc := sctx.GetSessionVars().StmtCtx
 	totalCount := float64(0)
 	isSingleCol := len(idx.Info.Columns) == 1
 	for _, indexRange := range indexRanges {
@@ -1377,7 +1380,7 @@ func (idx *Index) GetRowCount(sc *stmtctx.StatementContext, coll *HistColl, inde
 		// If the first column's range is point.
 		if rangePosition := GetOrdinalOfRangeCond(sc, indexRange); rangePosition > 0 && idx.StatsVer >= Version2 && coll != nil {
 			var expBackoffSel float64
-			expBackoffSel, expBackoffSuccess, err = idx.expBackoffEstimation(sc, coll, indexRange)
+			expBackoffSel, expBackoffSuccess, err = idx.expBackoffEstimation(sctx, coll, indexRange)
 			if err != nil {
 				return 0, err
 			}
@@ -1408,7 +1411,7 @@ func (idx *Index) GetRowCount(sc *stmtctx.StatementContext, coll *HistColl, inde
 }
 
 // expBackoffEstimation estimate the multi-col cases following the Exponential Backoff. See comment below for details.
-func (idx *Index) expBackoffEstimation(sc *stmtctx.StatementContext, coll *HistColl, indexRange *ranger.Range) (float64, bool, error) {
+func (idx *Index) expBackoffEstimation(sctx sessionctx.Context, coll *HistColl, indexRange *ranger.Range) (float64, bool, error) {
 	tmpRan := []*ranger.Range{
 		{
 			LowVal:  make([]types.Datum, 1),
@@ -1435,9 +1438,9 @@ func (idx *Index) expBackoffEstimation(sc *stmtctx.StatementContext, coll *HistC
 			err   error
 		)
 		if anotherIdxID, ok := coll.ColID2IdxID[colID]; ok && anotherIdxID != idx.ID {
-			count, err = coll.GetRowCountByIndexRanges(sc, anotherIdxID, tmpRan)
-		} else if col, ok := coll.Columns[colID]; ok && !col.IsInvalid(sc, coll.Pseudo) {
-			count, err = coll.GetRowCountByColumnRanges(sc, colID, tmpRan)
+			count, err = coll.GetRowCountByIndexRanges(sctx, anotherIdxID, tmpRan)
+		} else if col, ok := coll.Columns[colID]; ok && !col.IsInvalid(sctx, coll.Pseudo) {
+			count, err = coll.GetRowCountByColumnRanges(sctx, colID, tmpRan)
 		} else {
 			continue
 		}
@@ -1471,12 +1474,12 @@ func (idx *Index) expBackoffEstimation(sc *stmtctx.StatementContext, coll *HistC
 	return singleColumnEstResults[0] * math.Sqrt(singleColumnEstResults[1]) * math.Sqrt(math.Sqrt(singleColumnEstResults[2])) * math.Sqrt(math.Sqrt(math.Sqrt(singleColumnEstResults[3]))), true, nil
 }
 
-type countByRangeFunc = func(*stmtctx.StatementContext, int64, []*ranger.Range) (float64, error)
+type countByRangeFunc = func(sessionctx.Context, int64, []*ranger.Range) (float64, error)
 
 // newHistogramBySelectivity fulfills the content of new histogram by the given selectivity result.
 // TODO: Datum is not efficient, try to avoid using it here.
 //  Also, there're redundant calculation with Selectivity(). We need to reduce it too.
-func newHistogramBySelectivity(sc *stmtctx.StatementContext, histID int64, oldHist, newHist *Histogram, ranges []*ranger.Range, cntByRangeFunc countByRangeFunc) error {
+func newHistogramBySelectivity(sctx sessionctx.Context, histID int64, oldHist, newHist *Histogram, ranges []*ranger.Range, cntByRangeFunc countByRangeFunc) error {
 	cntPerVal := int64(oldHist.AvgCountPerNotNullValue(int64(oldHist.TotalRowCount())))
 	var totCnt int64
 	for boundIdx, ranIdx, highRangeIdx := 0, 0, 0; boundIdx < oldHist.Bounds.NumRows() && ranIdx < len(ranges); boundIdx, ranIdx = boundIdx+2, highRangeIdx {
@@ -1489,7 +1492,7 @@ func newHistogramBySelectivity(sc *stmtctx.StatementContext, histID int64, oldHi
 		if ranIdx == highRangeIdx {
 			continue
 		}
-		cnt, err := cntByRangeFunc(sc, histID, ranges[ranIdx:highRangeIdx])
+		cnt, err := cntByRangeFunc(sctx, histID, ranges[ranIdx:highRangeIdx])
 		// This should not happen.
 		if err != nil {
 			return err
@@ -1565,7 +1568,7 @@ func (idx *Index) newIndexBySelectivity(sc *stmtctx.StatementContext, statsNode
 }
 
 // NewHistCollBySelectivity creates new HistColl by the given statsNodes.
-func (coll *HistColl) NewHistCollBySelectivity(sc *stmtctx.StatementContext, statsNodes []*StatsNode) *HistColl {
+func (coll *HistColl) NewHistCollBySelectivity(sctx sessionctx.Context, statsNodes []*StatsNode) *HistColl {
 	newColl := &HistColl{
 		Columns:       make(map[int64]*Column),
 		Indices:       make(map[int64]*Index),
@@ -1579,7 +1582,7 @@ func (coll *HistColl) NewHistCollBySelectivity(sc *stmtctx.StatementContext, sta
 			if !ok {
 				continue
 			}
-			newIdxHist, err := idxHist.newIndexBySelectivity(sc, node)
+			newIdxHist, err := idxHist.newIndexBySelectivity(sctx.GetSessionVars().StmtCtx, node)
 			if err != nil {
 				logutil.BgLogger().Warn("[Histogram-in-plan]: something wrong happened when calculating row count, "+
 					"failed to build histogram for index %v of table %v",
@@ -1601,7 +1604,7 @@ func (coll *HistColl) NewHistCollBySelectivity(sc *stmtctx.StatementContext, sta
 		}
 		newCol.Histogram = *NewHistogram(oldCol.ID, int64(float64(oldCol.Histogram.NDV)*node.Selectivity), 0, 0, oldCol.Tp, chunk.InitialCapacity, 0)
 		var err error
-		splitRanges, ok := oldCol.Histogram.SplitRange(sc, node.Ranges, false)
+		splitRanges, ok := oldCol.Histogram.SplitRange(sctx.GetSessionVars().StmtCtx, node.Ranges, false)
 		if !ok {
 			logutil.BgLogger().Warn("[Histogram-in-plan]: the type of histogram and ranges mismatch")
 			continue
@@ -1619,9 +1622,9 @@ func (coll *HistColl) NewHistCollBySelectivity(sc *stmtctx.StatementContext, sta
 			}
 		}
 		if oldCol.IsHandle {
-			err = newHistogramBySelectivity(sc, node.ID, &oldCol.Histogram, &newCol.Histogram, splitRanges, coll.GetRowCountByIntColumnRanges)
+			err = newHistogramBySelectivity(sctx, node.ID, &oldCol.Histogram, &newCol.Histogram, splitRanges, coll.GetRowCountByIntColumnRanges)
 		} else {
-			err = newHistogramBySelectivity(sc, node.ID, &oldCol.Histogram, &newCol.Histogram, splitRanges, coll.GetRowCountByColumnRanges)
+			err = newHistogramBySelectivity(sctx, node.ID, &oldCol.Histogram, &newCol.Histogram, splitRanges, coll.GetRowCountByColumnRanges)
 		}
 		if err != nil {
 			logutil.BgLogger().Warn("[Histogram-in-plan]: something wrong happened when calculating row count",
diff --git a/statistics/histogram_test.go b/statistics/histogram_test.go
index 9a0698133711e..15e4d696de1ee 100644
--- a/statistics/histogram_test.go
+++ b/statistics/histogram_test.go
@@ -29,7 +29,6 @@ import (
 )
 
 func TestNewHistogramBySelectivity(t *testing.T) {
-	t.Parallel()
 	coll := &HistColl{
 		Count:   330,
 		Columns: make(map[int64]*Column),
@@ -93,7 +92,7 @@ num: 54 lower_bound: kkkkk upper_bound: ooooo repeats: 0 ndv: 0
 num: 60 lower_bound: oooooo upper_bound: sssss repeats: 0 ndv: 0
 num: 60 lower_bound: ssssssu upper_bound: yyyyy repeats: 0 ndv: 0`
 
-	newColl := coll.NewHistCollBySelectivity(sc, []*StatsNode{node, node2})
+	newColl := coll.NewHistCollBySelectivity(ctx, []*StatsNode{node, node2})
 	require.Equal(t, intColResult, newColl.Columns[1].String())
 	require.Equal(t, stringColResult, newColl.Columns[2].String())
 
@@ -120,12 +119,11 @@ num: 30 lower_bound: 3 upper_bound: 5 repeats: 10 ndv: 0
 num: 30 lower_bound: 9 upper_bound: 11 repeats: 10 ndv: 0
 num: 30 lower_bound: 12 upper_bound: 14 repeats: 10 ndv: 0`
 
-	newColl = coll.NewHistCollBySelectivity(sc, []*StatsNode{node3})
+	newColl = coll.NewHistCollBySelectivity(ctx, []*StatsNode{node3})
 	require.Equal(t, idxResult, newColl.Indices[0].String())
 }
 
 func TestTruncateHistogram(t *testing.T) {
-	t.Parallel()
 	hist := NewHistogram(0, 0, 0, 0, types.NewFieldType(mysql.TypeLonglong), 1, 0)
 	low, high := types.NewIntDatum(0), types.NewIntDatum(1)
 	hist.AppendBucket(&low, &high, 0, 1)
@@ -136,7 +134,6 @@ func TestTruncateHistogram(t *testing.T) {
 }
 
 func TestValueToString4InvalidKey(t *testing.T) {
-	t.Parallel()
 	bytes, err := codec.EncodeKey(nil, nil, types.NewDatum(1), types.NewDatum(0.5))
 	require.NoError(t, err)
 	// Append invalid flag.
@@ -174,7 +171,6 @@ func genHist4Test(t *testing.T, buckets []*bucket4Test, totColSize int64) *Histo
 }
 
 func TestMergePartitionLevelHist(t *testing.T) {
-	t.Parallel()
 	type testCase struct {
 		partitionHists  [][]*bucket4Test
 		totColSize      []int64
@@ -428,7 +424,6 @@ func genBucket4Merging4Test(lower, upper, ndv, disjointNDV int64) bucket4Merging
 }
 
 func TestMergeBucketNDV(t *testing.T) {
-	t.Parallel()
 	type testData struct {
 		left   bucket4Merging
 		right  bucket4Merging
diff --git a/statistics/integration_test.go b/statistics/integration_test.go
index 5ecdabd2fe7e8..47148c7daffe1 100644
--- a/statistics/integration_test.go
+++ b/statistics/integration_test.go
@@ -28,7 +28,6 @@ import (
 )
 
 func TestChangeVerTo2Behavior(t *testing.T) {
-	t.Parallel()
 	store, dom, clean := testkit.CreateMockStoreAndDomain(t)
 	defer clean()
 	tk := testkit.NewTestKit(t, store)
@@ -103,7 +102,6 @@ func TestChangeVerTo2Behavior(t *testing.T) {
 }
 
 func TestFastAnalyzeOnVer2(t *testing.T) {
-	t.Parallel()
 	store, dom, clean := testkit.CreateMockStoreAndDomain(t)
 	defer clean()
 	tk := testkit.NewTestKit(t, store)
@@ -152,7 +150,6 @@ func TestFastAnalyzeOnVer2(t *testing.T) {
 }
 
 func TestIncAnalyzeOnVer2(t *testing.T) {
-	t.Parallel()
 	store, dom, clean := testkit.CreateMockStoreAndDomain(t)
 	defer clean()
 	tk := testkit.NewTestKit(t, store)
@@ -180,7 +177,6 @@ func TestIncAnalyzeOnVer2(t *testing.T) {
 }
 
 func TestExpBackoffEstimation(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 	tk := testkit.NewTestKit(t, store)
@@ -217,7 +213,6 @@ func TestExpBackoffEstimation(t *testing.T) {
 }
 
 func TestGlobalStats(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 	tk := testkit.NewTestKit(t, store)
@@ -314,7 +309,6 @@ func TestGlobalStats(t *testing.T) {
 }
 
 func TestNULLOnFullSampling(t *testing.T) {
-	t.Parallel()
 	store, dom, clean := testkit.CreateMockStoreAndDomain(t)
 	defer clean()
 	tk := testkit.NewTestKit(t, store)
@@ -350,7 +344,6 @@ func TestNULLOnFullSampling(t *testing.T) {
 }
 
 func TestAnalyzeSnapshot(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 	tk := testkit.NewTestKit(t, store)
@@ -380,7 +373,6 @@ func TestAnalyzeSnapshot(t *testing.T) {
 }
 
 func TestHistogramsWithSameTxnTS(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 	tk := testkit.NewTestKit(t, store)
@@ -402,7 +394,6 @@ func TestHistogramsWithSameTxnTS(t *testing.T) {
 }
 
 func TestAnalyzeLongString(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 	tk := testkit.NewTestKit(t, store)
diff --git a/statistics/sample_test.go b/statistics/sample_test.go
index e22311ec7b298..97a00e55dfa8e 100644
--- a/statistics/sample_test.go
+++ b/statistics/sample_test.go
@@ -56,7 +56,6 @@ func recordSetForDistributedSamplingTest(size, batch int) []*recordSet {
 }
 
 func TestWeightedSampling(t *testing.T) {
-	t.Parallel()
 	sampleNum := int64(20)
 	rowNum := 100
 	loopCnt := 1000
@@ -95,7 +94,6 @@ func TestWeightedSampling(t *testing.T) {
 }
 
 func TestDistributedWeightedSampling(t *testing.T) {
-	t.Parallel()
 	sampleNum := int64(10)
 	rowNum := 100
 	loopCnt := 1500
@@ -139,7 +137,6 @@ func TestDistributedWeightedSampling(t *testing.T) {
 }
 
 func TestBuildStatsOnRowSample(t *testing.T) {
-	t.Parallel()
 	ctx := mock.NewContext()
 	sketch := NewFMSketch(1000)
 	data := make([]*SampleItem, 0, 8)
diff --git a/statistics/scalar_test.go b/statistics/scalar_test.go
index 9eeeec0184ac2..260716d121365 100644
--- a/statistics/scalar_test.go
+++ b/statistics/scalar_test.go
@@ -61,8 +61,6 @@ func getUnsignedFieldType() *types.FieldType {
 }
 
 func TestCalcFraction(t *testing.T) {
-	t.Parallel()
-
 	tests := []struct {
 		lower    types.Datum
 		upper    types.Datum
@@ -179,8 +177,6 @@ func TestCalcFraction(t *testing.T) {
 }
 
 func TestEnumRangeValues(t *testing.T) {
-	t.Parallel()
-
 	tests := []struct {
 		low         types.Datum
 		high        types.Datum
diff --git a/statistics/selectivity.go b/statistics/selectivity.go
index 86321d561e954..45db1cebf9b1c 100644
--- a/statistics/selectivity.go
+++ b/statistics/selectivity.go
@@ -27,7 +27,6 @@ import (
 	"github.com/pingcap/tidb/parser/mysql"
 	planutil "github.com/pingcap/tidb/planner/util"
 	"github.com/pingcap/tidb/sessionctx"
-	"github.com/pingcap/tidb/sessionctx/stmtctx"
 	"github.com/pingcap/tidb/types"
 	driver "github.com/pingcap/tidb/types/parser_driver"
 	"github.com/pingcap/tidb/util/chunk"
@@ -193,7 +192,7 @@ func (coll *HistColl) Selectivity(ctx sessionctx.Context, exprs []expression.Exp
 	if len(exprs) > 63 || (len(coll.Columns) == 0 && len(coll.Indices) == 0) {
 		ret = pseudoSelectivity(coll, exprs)
 		if sc.EnableOptimizerCETrace {
-			CETraceExpr(sc, tableID, "Table Stats-Pseudo-Expression", expression.ComposeCNFCondition(ctx, exprs...), ret*float64(coll.Count))
+			CETraceExpr(ctx, tableID, "Table Stats-Pseudo-Expression", expression.ComposeCNFCondition(ctx, exprs...), ret*float64(coll.Count))
 		}
 		return ret, nil, nil
 	}
@@ -210,7 +209,7 @@ func (coll *HistColl) Selectivity(ctx sessionctx.Context, exprs []expression.Exp
 			continue
 		}
 
-		if colHist := coll.Columns[c.UniqueID]; colHist == nil || colHist.IsInvalid(sc, coll.Pseudo) {
+		if colHist := coll.Columns[c.UniqueID]; colHist == nil || colHist.IsInvalid(ctx, coll.Pseudo) {
 			ret *= 1.0 / pseudoEqualRate
 			continue
 		}
@@ -236,14 +235,14 @@ func (coll *HistColl) Selectivity(ctx sessionctx.Context, exprs []expression.Exp
 			if colInfo.IsHandle {
 				nodes[len(nodes)-1].Tp = PkType
 				var cnt float64
-				cnt, err = coll.GetRowCountByIntColumnRanges(sc, id, ranges)
+				cnt, err = coll.GetRowCountByIntColumnRanges(ctx, id, ranges)
 				if err != nil {
 					return 0, nil, errors.Trace(err)
 				}
 				nodes[len(nodes)-1].Selectivity = cnt / float64(coll.Count)
 				continue
 			}
-			cnt, err := coll.GetRowCountByColumnRanges(sc, id, ranges)
+			cnt, err := coll.GetRowCountByColumnRanges(ctx, id, ranges)
 			if err != nil {
 				return 0, nil, errors.Trace(err)
 			}
@@ -274,7 +273,7 @@ func (coll *HistColl) Selectivity(ctx sessionctx.Context, exprs []expression.Exp
 			if err != nil {
 				return 0, nil, errors.Trace(err)
 			}
-			cnt, err := coll.GetRowCountByIndexRanges(sc, id, ranges)
+			cnt, err := coll.GetRowCountByIndexRanges(ctx, id, ranges)
 			if err != nil {
 				return 0, nil, errors.Trace(err)
 			}
@@ -314,7 +313,7 @@ func (coll *HistColl) Selectivity(ctx sessionctx.Context, exprs []expression.Exp
 				}
 			}
 			expr := expression.ComposeCNFCondition(ctx, curExpr...)
-			CETraceExpr(sc, tableID, "Table Stats-Expression-CNF", expr, ret*float64(coll.Count))
+			CETraceExpr(ctx, tableID, "Table Stats-Expression-CNF", expr, ret*float64(coll.Count))
 		}
 	}
 
@@ -372,7 +371,7 @@ func (coll *HistColl) Selectivity(ctx sessionctx.Context, exprs []expression.Exp
 				selectivity = selectivity + curSelectivity - selectivity*curSelectivity
 				if sc.EnableOptimizerCETrace {
 					// Tracing for the expression estimation results of this DNF.
-					CETraceExpr(sc, tableID, "Table Stats-Expression-DNF", scalarCond, selectivity*float64(coll.Count))
+					CETraceExpr(ctx, tableID, "Table Stats-Expression-DNF", scalarCond, selectivity*float64(coll.Count))
 				}
 			}
 
@@ -384,7 +383,7 @@ func (coll *HistColl) Selectivity(ctx sessionctx.Context, exprs []expression.Exp
 				// Tracing for the expression estimation results after applying the DNF estimation result.
 				curExpr = append(curExpr, remainedExprs[i])
 				expr := expression.ComposeCNFCondition(ctx, curExpr...)
-				CETraceExpr(sc, tableID, "Table Stats-Expression-CNF", expr, ret*float64(coll.Count))
+				CETraceExpr(ctx, tableID, "Table Stats-Expression-CNF", expr, ret*float64(coll.Count))
 			}
 		}
 	}
@@ -396,7 +395,7 @@ func (coll *HistColl) Selectivity(ctx sessionctx.Context, exprs []expression.Exp
 	if sc.EnableOptimizerCETrace {
 		// Tracing for the expression estimation results after applying the default selectivity.
 		totalExpr := expression.ComposeCNFCondition(ctx, remainedExprs...)
-		CETraceExpr(sc, tableID, "Table Stats-Expression-CNF", totalExpr, ret*float64(coll.Count))
+		CETraceExpr(ctx, tableID, "Table Stats-Expression-CNF", totalExpr, ret*float64(coll.Count))
 	}
 	return ret, nodes, nil
 }
@@ -520,7 +519,7 @@ func FindPrefixOfIndexByCol(cols []*expression.Column, idxColIDs []int64, cached
 }
 
 // CETraceExpr appends an expression and related information into CE trace
-func CETraceExpr(sc *stmtctx.StatementContext, tableID int64, tp string, expr expression.Expression, rowCount float64) {
+func CETraceExpr(sctx sessionctx.Context, tableID int64, tp string, expr expression.Expression, rowCount float64) {
 	exprStr, err := ExprToString(expr)
 	if err != nil {
 		logutil.BgLogger().Debug("[OptimizerTrace] Failed to trace CE of an expression",
@@ -533,6 +532,7 @@ func CETraceExpr(sc *stmtctx.StatementContext, tableID int64, tp string, expr ex
 		Expr:     exprStr,
 		RowCount: uint64(rowCount),
 	}
+	sc := sctx.GetSessionVars().StmtCtx
 	sc.OptimizerCETrace = append(sc.OptimizerCETrace, &rec)
 }
 
diff --git a/statistics/selectivity_serial_test.go b/statistics/selectivity_serial_test.go
index 7fdbf09c757dc..a128be3850049 100644
--- a/statistics/selectivity_serial_test.go
+++ b/statistics/selectivity_serial_test.go
@@ -28,13 +28,13 @@ import (
 	plannercore "github.com/pingcap/tidb/planner/core"
 	"github.com/pingcap/tidb/session"
 	"github.com/pingcap/tidb/sessionctx"
-	"github.com/pingcap/tidb/sessionctx/stmtctx"
 	"github.com/pingcap/tidb/sessionctx/variable"
 	"github.com/pingcap/tidb/statistics"
 	"github.com/pingcap/tidb/statistics/handle"
 	"github.com/pingcap/tidb/testkit"
 	"github.com/pingcap/tidb/testkit/testdata"
 	"github.com/pingcap/tidb/util/collate"
+	"github.com/pingcap/tidb/util/mock"
 	"github.com/stretchr/testify/require"
 )
 
@@ -125,9 +125,9 @@ func TestOutOfRangeEstimation(t *testing.T) {
 	table, err := dom.InfoSchema().TableByName(model.NewCIStr("test"), model.NewCIStr("t"))
 	require.NoError(t, err)
 	statsTbl := h.GetTableStats(table.Meta())
-	sc := &stmtctx.StatementContext{}
+	sctx := mock.NewContext()
 	col := statsTbl.Columns[table.Meta().Columns[0].ID]
-	count, err := col.GetColumnRowCount(sc, getRange(900, 900), statsTbl.Count, false)
+	count, err := col.GetColumnRowCount(sctx, getRange(900, 900), statsTbl.Count, false)
 	require.NoError(t, err)
 	// Because the ANALYZE collect data by random sampling, so the result is not an accurate value.
 	// so we use a range here.
@@ -147,7 +147,7 @@ func TestOutOfRangeEstimation(t *testing.T) {
 	statsSuiteData.GetTestCases(t, &input, &output)
 	increasedTblRowCount := int64(float64(statsTbl.Count) * 1.5)
 	for i, ran := range input {
-		count, err = col.GetColumnRowCount(sc, getRange(ran.Start, ran.End), increasedTblRowCount, false)
+		count, err = col.GetColumnRowCount(sctx, getRange(ran.Start, ran.End), increasedTblRowCount, false)
 		require.NoError(t, err)
 		testdata.OnRecord(func() {
 			output[i].Start = ran.Start
@@ -184,26 +184,26 @@ func TestEstimationForUnknownValues(t *testing.T) {
 	require.NoError(t, err)
 	statsTbl := h.GetTableStats(table.Meta())
 
-	sc := &stmtctx.StatementContext{}
+	sctx := mock.NewContext()
 	colID := table.Meta().Columns[0].ID
-	count, err := statsTbl.GetRowCountByColumnRanges(sc, colID, getRange(30, 30))
+	count, err := statsTbl.GetRowCountByColumnRanges(sctx, colID, getRange(30, 30))
 	require.NoError(t, err)
 	require.Equal(t, 0.2, count)
 
-	count, err = statsTbl.GetRowCountByColumnRanges(sc, colID, getRange(9, 30))
+	count, err = statsTbl.GetRowCountByColumnRanges(sctx, colID, getRange(9, 30))
 	require.NoError(t, err)
 	require.Equal(t, 7.2, count)
 
-	count, err = statsTbl.GetRowCountByColumnRanges(sc, colID, getRange(9, math.MaxInt64))
+	count, err = statsTbl.GetRowCountByColumnRanges(sctx, colID, getRange(9, math.MaxInt64))
 	require.NoError(t, err)
 	require.Equal(t, 7.2, count)
 
 	idxID := table.Meta().Indices[0].ID
-	count, err = statsTbl.GetRowCountByIndexRanges(sc, idxID, getRange(30, 30))
+	count, err = statsTbl.GetRowCountByIndexRanges(sctx, idxID, getRange(30, 30))
 	require.NoError(t, err)
 	require.Equal(t, 0.1, count)
 
-	count, err = statsTbl.GetRowCountByIndexRanges(sc, idxID, getRange(9, 30))
+	count, err = statsTbl.GetRowCountByIndexRanges(sctx, idxID, getRange(9, 30))
 	require.NoError(t, err)
 	require.Equal(t, 7.0, count)
 
@@ -215,7 +215,7 @@ func TestEstimationForUnknownValues(t *testing.T) {
 	statsTbl = h.GetTableStats(table.Meta())
 
 	colID = table.Meta().Columns[0].ID
-	count, err = statsTbl.GetRowCountByColumnRanges(sc, colID, getRange(1, 30))
+	count, err = statsTbl.GetRowCountByColumnRanges(sctx, colID, getRange(1, 30))
 	require.NoError(t, err)
 	require.Equal(t, 0.0, count)
 
@@ -228,12 +228,12 @@ func TestEstimationForUnknownValues(t *testing.T) {
 	statsTbl = h.GetTableStats(table.Meta())
 
 	colID = table.Meta().Columns[0].ID
-	count, err = statsTbl.GetRowCountByColumnRanges(sc, colID, getRange(2, 2))
+	count, err = statsTbl.GetRowCountByColumnRanges(sctx, colID, getRange(2, 2))
 	require.NoError(t, err)
 	require.Equal(t, 0.0, count)
 
 	idxID = table.Meta().Indices[0].ID
-	count, err = statsTbl.GetRowCountByIndexRanges(sc, idxID, getRange(2, 2))
+	count, err = statsTbl.GetRowCountByIndexRanges(sctx, idxID, getRange(2, 2))
 	require.NoError(t, err)
 	require.Equal(t, 0.0, count)
 }
@@ -252,22 +252,22 @@ func TestEstimationUniqueKeyEqualConds(t *testing.T) {
 	require.NoError(t, err)
 	statsTbl := dom.StatsHandle().GetTableStats(table.Meta())
 
-	sc := &stmtctx.StatementContext{}
+	sctx := mock.NewContext()
 	idxID := table.Meta().Indices[0].ID
-	count, err := statsTbl.GetRowCountByIndexRanges(sc, idxID, getRange(7, 7))
+	count, err := statsTbl.GetRowCountByIndexRanges(sctx, idxID, getRange(7, 7))
 	require.NoError(t, err)
 	require.Equal(t, 1.0, count)
 
-	count, err = statsTbl.GetRowCountByIndexRanges(sc, idxID, getRange(6, 6))
+	count, err = statsTbl.GetRowCountByIndexRanges(sctx, idxID, getRange(6, 6))
 	require.NoError(t, err)
 	require.Equal(t, 1.0, count)
 
 	colID := table.Meta().Columns[0].ID
-	count, err = statsTbl.GetRowCountByIntColumnRanges(sc, colID, getRange(7, 7))
+	count, err = statsTbl.GetRowCountByIntColumnRanges(sctx, colID, getRange(7, 7))
 	require.NoError(t, err)
 	require.Equal(t, 1.0, count)
 
-	count, err = statsTbl.GetRowCountByIntColumnRanges(sc, colID, getRange(6, 6))
+	count, err = statsTbl.GetRowCountByIntColumnRanges(sctx, colID, getRange(6, 6))
 	require.NoError(t, err)
 	require.Equal(t, 1.0, count)
 }
@@ -760,7 +760,7 @@ func TestSmallRangeEstimation(t *testing.T) {
 	table, err := dom.InfoSchema().TableByName(model.NewCIStr("test"), model.NewCIStr("t"))
 	require.NoError(t, err)
 	statsTbl := h.GetTableStats(table.Meta())
-	sc := &stmtctx.StatementContext{}
+	sctx := mock.NewContext()
 	col := statsTbl.Columns[table.Meta().Columns[0].ID]
 
 	var input []struct {
@@ -775,7 +775,7 @@ func TestSmallRangeEstimation(t *testing.T) {
 	statsSuiteData := statistics.GetStatsSuiteData()
 	statsSuiteData.GetTestCases(t, &input, &output)
 	for i, ran := range input {
-		count, err := col.GetColumnRowCount(sc, getRange(ran.Start, ran.End), statsTbl.Count, false)
+		count, err := col.GetColumnRowCount(sctx, getRange(ran.Start, ran.End), statsTbl.Count, false)
 		require.NoError(t, err)
 		testdata.OnRecord(func() {
 			output[i].Start = ran.Start
diff --git a/statistics/selectivity_test.go b/statistics/selectivity_test.go
index d77bfa2d397ef..3a2e73777f54d 100644
--- a/statistics/selectivity_test.go
+++ b/statistics/selectivity_test.go
@@ -130,7 +130,6 @@ func getRange(start, end int64) []*ranger.Range {
 }
 
 func TestSelectivityGreedyAlgo(t *testing.T) {
-	t.Parallel()
 	nodes := make([]*statistics.StatsNode, 3)
 	nodes[0] = statistics.MockStatsNode(1, 3, 2)
 	nodes[1] = statistics.MockStatsNode(2, 5, 2)
diff --git a/statistics/statistics_test.go b/statistics/statistics_test.go
index 53df0e04bd7be..c99802bd0314e 100644
--- a/statistics/statistics_test.go
+++ b/statistics/statistics_test.go
@@ -24,7 +24,6 @@ import (
 	"github.com/pingcap/tidb/parser/model"
 	"github.com/pingcap/tidb/parser/mysql"
 	"github.com/pingcap/tidb/sessionctx"
-	"github.com/pingcap/tidb/sessionctx/stmtctx"
 	"github.com/pingcap/tidb/types"
 	"github.com/pingcap/tidb/util/chunk"
 	"github.com/pingcap/tidb/util/collate"
@@ -134,7 +133,6 @@ func mockHistogram(lower, num int64) *Histogram {
 }
 
 func TestMergeHistogram(t *testing.T) {
-	t.Parallel()
 	tests := []struct {
 		leftLower  int64
 		leftNum    int64
@@ -190,7 +188,6 @@ func TestMergeHistogram(t *testing.T) {
 }
 
 func TestPseudoTable(t *testing.T) {
-	t.Parallel()
 	ti := &model.TableInfo{}
 	colInfo := &model.ColumnInfo{
 		ID:        1,
@@ -201,13 +198,13 @@ func TestPseudoTable(t *testing.T) {
 	tbl := PseudoTable(ti)
 	require.Equal(t, len(tbl.Columns), 1)
 	require.Greater(t, tbl.Count, int64(0))
-	sc := new(stmtctx.StatementContext)
-	count := tbl.ColumnLessRowCount(sc, types.NewIntDatum(100), colInfo.ID)
+	sctx := mock.NewContext()
+	count := tbl.ColumnLessRowCount(sctx, types.NewIntDatum(100), colInfo.ID)
 	require.Equal(t, 3333, int(count))
-	count, err := tbl.ColumnEqualRowCount(sc, types.NewIntDatum(1000), colInfo.ID)
+	count, err := tbl.ColumnEqualRowCount(sctx, types.NewIntDatum(1000), colInfo.ID)
 	require.NoError(t, err)
 	require.Equal(t, 10, int(count))
-	count, _ = tbl.ColumnBetweenRowCount(sc, types.NewIntDatum(1000), types.NewIntDatum(5000), colInfo.ID)
+	count, _ = tbl.ColumnBetweenRowCount(sctx, types.NewIntDatum(1000), types.NewIntDatum(5000), colInfo.ID)
 	require.Equal(t, 250, int(count))
 	ti.Columns = append(ti.Columns, &model.ColumnInfo{
 		ID:        2,
@@ -233,7 +230,6 @@ func buildCMSketch(values []types.Datum) *CMSketch {
 
 func SubTestColumnRange() func(*testing.T) {
 	return func(t *testing.T) {
-		t.Parallel()
 		s := createTestStatisticsSamples(t)
 		bucketCount := int64(256)
 		ctx := mock.NewContext()
@@ -261,50 +257,50 @@ func SubTestColumnRange() func(*testing.T) {
 			LowVal:  []types.Datum{{}},
 			HighVal: []types.Datum{types.MaxValueDatum()},
 		}}
-		count, err := tbl.GetRowCountByColumnRanges(sc, 0, ran)
+		count, err := tbl.GetRowCountByColumnRanges(ctx, 0, ran)
 		require.NoError(t, err)
 		require.Equal(t, 100000, int(count))
 		ran[0].LowVal[0] = types.MinNotNullDatum()
-		count, err = tbl.GetRowCountByColumnRanges(sc, 0, ran)
+		count, err = tbl.GetRowCountByColumnRanges(ctx, 0, ran)
 		require.NoError(t, err)
 		require.Equal(t, 99900, int(count))
 		ran[0].LowVal[0] = types.NewIntDatum(1000)
 		ran[0].LowExclude = true
 		ran[0].HighVal[0] = types.NewIntDatum(2000)
 		ran[0].HighExclude = true
-		count, err = tbl.GetRowCountByColumnRanges(sc, 0, ran)
+		count, err = tbl.GetRowCountByColumnRanges(ctx, 0, ran)
 		require.NoError(t, err)
 		require.Equal(t, 2500, int(count))
 		ran[0].LowExclude = false
 		ran[0].HighExclude = false
-		count, err = tbl.GetRowCountByColumnRanges(sc, 0, ran)
+		count, err = tbl.GetRowCountByColumnRanges(ctx, 0, ran)
 		require.NoError(t, err)
 		require.Equal(t, 2500, int(count))
 		ran[0].LowVal[0] = ran[0].HighVal[0]
-		count, err = tbl.GetRowCountByColumnRanges(sc, 0, ran)
+		count, err = tbl.GetRowCountByColumnRanges(ctx, 0, ran)
 		require.NoError(t, err)
 		require.Equal(t, 100, int(count))
 
 		tbl.Columns[0] = col
 		ran[0].LowVal[0] = types.Datum{}
 		ran[0].HighVal[0] = types.MaxValueDatum()
-		count, err = tbl.GetRowCountByColumnRanges(sc, 0, ran)
+		count, err = tbl.GetRowCountByColumnRanges(ctx, 0, ran)
 		require.NoError(t, err)
 		require.Equal(t, 100000, int(count))
 		ran[0].LowVal[0] = types.NewIntDatum(1000)
 		ran[0].LowExclude = true
 		ran[0].HighVal[0] = types.NewIntDatum(2000)
 		ran[0].HighExclude = true
-		count, err = tbl.GetRowCountByColumnRanges(sc, 0, ran)
+		count, err = tbl.GetRowCountByColumnRanges(ctx, 0, ran)
 		require.NoError(t, err)
 		require.Equal(t, 9998, int(count))
 		ran[0].LowExclude = false
 		ran[0].HighExclude = false
-		count, err = tbl.GetRowCountByColumnRanges(sc, 0, ran)
+		count, err = tbl.GetRowCountByColumnRanges(ctx, 0, ran)
 		require.NoError(t, err)
 		require.Equal(t, 10000, int(count))
 		ran[0].LowVal[0] = ran[0].HighVal[0]
-		count, err = tbl.GetRowCountByColumnRanges(sc, 0, ran)
+		count, err = tbl.GetRowCountByColumnRanges(ctx, 0, ran)
 		require.NoError(t, err)
 		require.Equal(t, 1, int(count))
 	}
@@ -312,11 +308,9 @@ func SubTestColumnRange() func(*testing.T) {
 
 func SubTestIntColumnRanges() func(*testing.T) {
 	return func(t *testing.T) {
-		t.Parallel()
 		s := createTestStatisticsSamples(t)
 		bucketCount := int64(256)
 		ctx := mock.NewContext()
-		sc := ctx.GetSessionVars().StmtCtx
 
 		s.pk.(*recordSet).cursor = 0
 		rowCount, hg, err := buildPK(ctx, bucketCount, 0, s.pk)
@@ -334,22 +328,22 @@ func SubTestIntColumnRanges() func(*testing.T) {
 			LowVal:  []types.Datum{types.NewIntDatum(math.MinInt64)},
 			HighVal: []types.Datum{types.NewIntDatum(math.MaxInt64)},
 		}}
-		count, err := tbl.GetRowCountByIntColumnRanges(sc, 0, ran)
+		count, err := tbl.GetRowCountByIntColumnRanges(ctx, 0, ran)
 		require.NoError(t, err)
 		require.Equal(t, 100000, int(count))
 		ran[0].LowVal[0].SetInt64(1000)
 		ran[0].HighVal[0].SetInt64(2000)
-		count, err = tbl.GetRowCountByIntColumnRanges(sc, 0, ran)
+		count, err = tbl.GetRowCountByIntColumnRanges(ctx, 0, ran)
 		require.NoError(t, err)
 		require.Equal(t, 1000, int(count))
 		ran[0].LowVal[0].SetInt64(1001)
 		ran[0].HighVal[0].SetInt64(1999)
-		count, err = tbl.GetRowCountByIntColumnRanges(sc, 0, ran)
+		count, err = tbl.GetRowCountByIntColumnRanges(ctx, 0, ran)
 		require.NoError(t, err)
 		require.Equal(t, 998, int(count))
 		ran[0].LowVal[0].SetInt64(1000)
 		ran[0].HighVal[0].SetInt64(1000)
-		count, err = tbl.GetRowCountByIntColumnRanges(sc, 0, ran)
+		count, err = tbl.GetRowCountByIntColumnRanges(ctx, 0, ran)
 		require.NoError(t, err)
 		require.Equal(t, 1, int(count))
 
@@ -357,49 +351,49 @@ func SubTestIntColumnRanges() func(*testing.T) {
 			LowVal:  []types.Datum{types.NewUintDatum(0)},
 			HighVal: []types.Datum{types.NewUintDatum(math.MaxUint64)},
 		}}
-		count, err = tbl.GetRowCountByIntColumnRanges(sc, 0, ran)
+		count, err = tbl.GetRowCountByIntColumnRanges(ctx, 0, ran)
 		require.NoError(t, err)
 		require.Equal(t, 100000, int(count))
 		ran[0].LowVal[0].SetUint64(1000)
 		ran[0].HighVal[0].SetUint64(2000)
-		count, err = tbl.GetRowCountByIntColumnRanges(sc, 0, ran)
+		count, err = tbl.GetRowCountByIntColumnRanges(ctx, 0, ran)
 		require.NoError(t, err)
 		require.Equal(t, 1000, int(count))
 		ran[0].LowVal[0].SetUint64(1001)
 		ran[0].HighVal[0].SetUint64(1999)
-		count, err = tbl.GetRowCountByIntColumnRanges(sc, 0, ran)
+		count, err = tbl.GetRowCountByIntColumnRanges(ctx, 0, ran)
 		require.NoError(t, err)
 		require.Equal(t, 998, int(count))
 		ran[0].LowVal[0].SetUint64(1000)
 		ran[0].HighVal[0].SetUint64(1000)
-		count, err = tbl.GetRowCountByIntColumnRanges(sc, 0, ran)
+		count, err = tbl.GetRowCountByIntColumnRanges(ctx, 0, ran)
 		require.NoError(t, err)
 		require.Equal(t, 1, int(count))
 
 		tbl.Columns[0] = col
 		ran[0].LowVal[0].SetInt64(math.MinInt64)
 		ran[0].HighVal[0].SetInt64(math.MaxInt64)
-		count, err = tbl.GetRowCountByIntColumnRanges(sc, 0, ran)
+		count, err = tbl.GetRowCountByIntColumnRanges(ctx, 0, ran)
 		require.NoError(t, err)
 		require.Equal(t, 100000, int(count))
 		ran[0].LowVal[0].SetInt64(1000)
 		ran[0].HighVal[0].SetInt64(2000)
-		count, err = tbl.GetRowCountByIntColumnRanges(sc, 0, ran)
+		count, err = tbl.GetRowCountByIntColumnRanges(ctx, 0, ran)
 		require.NoError(t, err)
 		require.Equal(t, 1001, int(count))
 		ran[0].LowVal[0].SetInt64(1001)
 		ran[0].HighVal[0].SetInt64(1999)
-		count, err = tbl.GetRowCountByIntColumnRanges(sc, 0, ran)
+		count, err = tbl.GetRowCountByIntColumnRanges(ctx, 0, ran)
 		require.NoError(t, err)
 		require.Equal(t, 999, int(count))
 		ran[0].LowVal[0].SetInt64(1000)
 		ran[0].HighVal[0].SetInt64(1000)
-		count, err = tbl.GetRowCountByIntColumnRanges(sc, 0, ran)
+		count, err = tbl.GetRowCountByIntColumnRanges(ctx, 0, ran)
 		require.NoError(t, err)
 		require.Equal(t, 1, int(count))
 
 		tbl.Count *= 10
-		count, err = tbl.GetRowCountByIntColumnRanges(sc, 0, ran)
+		count, err = tbl.GetRowCountByIntColumnRanges(ctx, 0, ran)
 		require.NoError(t, err)
 		require.Equal(t, 1, int(count))
 	}
@@ -407,11 +401,9 @@ func SubTestIntColumnRanges() func(*testing.T) {
 
 func SubTestIndexRanges() func(*testing.T) {
 	return func(t *testing.T) {
-		t.Parallel()
 		s := createTestStatisticsSamples(t)
 		bucketCount := int64(256)
 		ctx := mock.NewContext()
-		sc := ctx.GetSessionVars().StmtCtx
 
 		s.rc.(*recordSet).cursor = 0
 		rowCount, hg, cms, err := buildIndex(ctx, bucketCount, 0, s.rc)
@@ -430,51 +422,51 @@ func SubTestIndexRanges() func(*testing.T) {
 			LowVal:  []types.Datum{types.MinNotNullDatum()},
 			HighVal: []types.Datum{types.MaxValueDatum()},
 		}}
-		count, err := tbl.GetRowCountByIndexRanges(sc, 0, ran)
+		count, err := tbl.GetRowCountByIndexRanges(ctx, 0, ran)
 		require.NoError(t, err)
 		require.Equal(t, 99900, int(count))
 		ran[0].LowVal[0] = types.NewIntDatum(1000)
 		ran[0].HighVal[0] = types.NewIntDatum(2000)
-		count, err = tbl.GetRowCountByIndexRanges(sc, 0, ran)
+		count, err = tbl.GetRowCountByIndexRanges(ctx, 0, ran)
 		require.NoError(t, err)
 		require.Equal(t, 2500, int(count))
 		ran[0].LowVal[0] = types.NewIntDatum(1001)
 		ran[0].HighVal[0] = types.NewIntDatum(1999)
-		count, err = tbl.GetRowCountByIndexRanges(sc, 0, ran)
+		count, err = tbl.GetRowCountByIndexRanges(ctx, 0, ran)
 		require.NoError(t, err)
 		require.Equal(t, 2500, int(count))
 		ran[0].LowVal[0] = types.NewIntDatum(1000)
 		ran[0].HighVal[0] = types.NewIntDatum(1000)
-		count, err = tbl.GetRowCountByIndexRanges(sc, 0, ran)
+		count, err = tbl.GetRowCountByIndexRanges(ctx, 0, ran)
 		require.NoError(t, err)
 		require.Equal(t, 100, int(count))
 
 		tbl.Indices[0] = &Index{Info: &model.IndexInfo{Columns: []*model.IndexColumn{{Offset: 0}}, Unique: true}}
 		ran[0].LowVal[0] = types.NewIntDatum(1000)
 		ran[0].HighVal[0] = types.NewIntDatum(1000)
-		count, err = tbl.GetRowCountByIndexRanges(sc, 0, ran)
+		count, err = tbl.GetRowCountByIndexRanges(ctx, 0, ran)
 		require.NoError(t, err)
 		require.Equal(t, 1, int(count))
 
 		tbl.Indices[0] = idx
 		ran[0].LowVal[0] = types.MinNotNullDatum()
 		ran[0].HighVal[0] = types.MaxValueDatum()
-		count, err = tbl.GetRowCountByIndexRanges(sc, 0, ran)
+		count, err = tbl.GetRowCountByIndexRanges(ctx, 0, ran)
 		require.NoError(t, err)
 		require.Equal(t, 100000, int(count))
 		ran[0].LowVal[0] = types.NewIntDatum(1000)
 		ran[0].HighVal[0] = types.NewIntDatum(2000)
-		count, err = tbl.GetRowCountByIndexRanges(sc, 0, ran)
+		count, err = tbl.GetRowCountByIndexRanges(ctx, 0, ran)
 		require.NoError(t, err)
 		require.Equal(t, 1000, int(count))
 		ran[0].LowVal[0] = types.NewIntDatum(1001)
 		ran[0].HighVal[0] = types.NewIntDatum(1990)
-		count, err = tbl.GetRowCountByIndexRanges(sc, 0, ran)
+		count, err = tbl.GetRowCountByIndexRanges(ctx, 0, ran)
 		require.NoError(t, err)
 		require.Equal(t, 989, int(count))
 		ran[0].LowVal[0] = types.NewIntDatum(1000)
 		ran[0].HighVal[0] = types.NewIntDatum(1000)
-		count, err = tbl.GetRowCountByIndexRanges(sc, 0, ran)
+		count, err = tbl.GetRowCountByIndexRanges(ctx, 0, ran)
 		require.NoError(t, err)
 		require.Equal(t, 0, int(count))
 	}
diff --git a/statistics/table.go b/statistics/table.go
index 358744716525b..10e08001c7528 100644
--- a/statistics/table.go
+++ b/statistics/table.go
@@ -285,27 +285,28 @@ func (t *Table) IsOutdated() bool {
 }
 
 // ColumnGreaterRowCount estimates the row count where the column greater than value.
-func (t *Table) ColumnGreaterRowCount(sc *stmtctx.StatementContext, value types.Datum, colID int64) float64 {
+func (t *Table) ColumnGreaterRowCount(sctx sessionctx.Context, value types.Datum, colID int64) float64 {
 	c, ok := t.Columns[colID]
-	if !ok || c.IsInvalid(sc, t.Pseudo) {
+	if !ok || c.IsInvalid(sctx, t.Pseudo) {
 		return float64(t.Count) / pseudoLessRate
 	}
 	return c.greaterRowCount(value) * c.GetIncreaseFactor(t.Count)
 }
 
 // ColumnLessRowCount estimates the row count where the column less than value. Note that null values are not counted.
-func (t *Table) ColumnLessRowCount(sc *stmtctx.StatementContext, value types.Datum, colID int64) float64 {
+func (t *Table) ColumnLessRowCount(sctx sessionctx.Context, value types.Datum, colID int64) float64 {
 	c, ok := t.Columns[colID]
-	if !ok || c.IsInvalid(sc, t.Pseudo) {
+	if !ok || c.IsInvalid(sctx, t.Pseudo) {
 		return float64(t.Count) / pseudoLessRate
 	}
 	return c.lessRowCount(value) * c.GetIncreaseFactor(t.Count)
 }
 
 // ColumnBetweenRowCount estimates the row count where column greater or equal to a and less than b.
-func (t *Table) ColumnBetweenRowCount(sc *stmtctx.StatementContext, a, b types.Datum, colID int64) (float64, error) {
+func (t *Table) ColumnBetweenRowCount(sctx sessionctx.Context, a, b types.Datum, colID int64) (float64, error) {
+	sc := sctx.GetSessionVars().StmtCtx
 	c, ok := t.Columns[colID]
-	if !ok || c.IsInvalid(sc, t.Pseudo) {
+	if !ok || c.IsInvalid(sctx, t.Pseudo) {
 		return float64(t.Count) / pseudoBetweenRate, nil
 	}
 	aEncoded, err := codec.EncodeKey(sc, nil, a)
@@ -316,7 +317,7 @@ func (t *Table) ColumnBetweenRowCount(sc *stmtctx.StatementContext, a, b types.D
 	if err != nil {
 		return 0, err
 	}
-	count := c.BetweenRowCount(sc, a, b, aEncoded, bEncoded)
+	count := c.BetweenRowCount(sctx, a, b, aEncoded, bEncoded)
 	if a.IsNull() {
 		count += float64(c.NullCount)
 	}
@@ -324,25 +325,26 @@ func (t *Table) ColumnBetweenRowCount(sc *stmtctx.StatementContext, a, b types.D
 }
 
 // ColumnEqualRowCount estimates the row count where the column equals to value.
-func (t *Table) ColumnEqualRowCount(sc *stmtctx.StatementContext, value types.Datum, colID int64) (float64, error) {
+func (t *Table) ColumnEqualRowCount(sctx sessionctx.Context, value types.Datum, colID int64) (float64, error) {
 	c, ok := t.Columns[colID]
-	if !ok || c.IsInvalid(sc, t.Pseudo) {
+	if !ok || c.IsInvalid(sctx, t.Pseudo) {
 		return float64(t.Count) / pseudoEqualRate, nil
 	}
-	encodedVal, err := codec.EncodeKey(sc, nil, value)
+	encodedVal, err := codec.EncodeKey(sctx.GetSessionVars().StmtCtx, nil, value)
 	if err != nil {
 		return 0, err
 	}
-	result, err := c.equalRowCount(sc, value, encodedVal, t.ModifyCount)
+	result, err := c.equalRowCount(sctx, value, encodedVal, t.ModifyCount)
 	result *= c.GetIncreaseFactor(t.Count)
 	return result, errors.Trace(err)
 }
 
 // GetRowCountByIntColumnRanges estimates the row count by a slice of IntColumnRange.
-func (coll *HistColl) GetRowCountByIntColumnRanges(sc *stmtctx.StatementContext, colID int64, intRanges []*ranger.Range) (float64, error) {
+func (coll *HistColl) GetRowCountByIntColumnRanges(sctx sessionctx.Context, colID int64, intRanges []*ranger.Range) (float64, error) {
+	sc := sctx.GetSessionVars().StmtCtx
 	var result float64
 	c, ok := coll.Columns[colID]
-	if !ok || c.IsInvalid(sc, coll.Pseudo) {
+	if !ok || c.IsInvalid(sctx, coll.Pseudo) {
 		if len(intRanges) == 0 {
 			return 0, nil
 		}
@@ -352,36 +354,38 @@ func (coll *HistColl) GetRowCountByIntColumnRanges(sc *stmtctx.StatementContext,
 			result = getPseudoRowCountByUnsignedIntRanges(intRanges, float64(coll.Count))
 		}
 		if sc.EnableOptimizerCETrace && ok {
-			CETraceRange(sc, coll.PhysicalID, []string{c.Info.Name.O}, intRanges, "Column Stats-Pseudo", uint64(result))
+			CETraceRange(sctx, coll.PhysicalID, []string{c.Info.Name.O}, intRanges, "Column Stats-Pseudo", uint64(result))
 		}
 		return result, nil
 	}
-	result, err := c.GetColumnRowCount(sc, intRanges, coll.Count, true)
+	result, err := c.GetColumnRowCount(sctx, intRanges, coll.Count, true)
 	if sc.EnableOptimizerCETrace {
-		CETraceRange(sc, coll.PhysicalID, []string{c.Info.Name.O}, intRanges, "Column Stats", uint64(result))
+		CETraceRange(sctx, coll.PhysicalID, []string{c.Info.Name.O}, intRanges, "Column Stats", uint64(result))
 	}
 	return result, errors.Trace(err)
 }
 
 // GetRowCountByColumnRanges estimates the row count by a slice of Range.
-func (coll *HistColl) GetRowCountByColumnRanges(sc *stmtctx.StatementContext, colID int64, colRanges []*ranger.Range) (float64, error) {
+func (coll *HistColl) GetRowCountByColumnRanges(sctx sessionctx.Context, colID int64, colRanges []*ranger.Range) (float64, error) {
+	sc := sctx.GetSessionVars().StmtCtx
 	c, ok := coll.Columns[colID]
-	if !ok || c.IsInvalid(sc, coll.Pseudo) {
+	if !ok || c.IsInvalid(sctx, coll.Pseudo) {
 		result, err := GetPseudoRowCountByColumnRanges(sc, float64(coll.Count), colRanges, 0)
 		if err == nil && sc.EnableOptimizerCETrace && ok {
-			CETraceRange(sc, coll.PhysicalID, []string{c.Info.Name.O}, colRanges, "Column Stats-Pseudo", uint64(result))
+			CETraceRange(sctx, coll.PhysicalID, []string{c.Info.Name.O}, colRanges, "Column Stats-Pseudo", uint64(result))
 		}
 		return result, err
 	}
-	result, err := c.GetColumnRowCount(sc, colRanges, coll.Count, false)
+	result, err := c.GetColumnRowCount(sctx, colRanges, coll.Count, false)
 	if sc.EnableOptimizerCETrace {
-		CETraceRange(sc, coll.PhysicalID, []string{c.Info.Name.O}, colRanges, "Column Stats", uint64(result))
+		CETraceRange(sctx, coll.PhysicalID, []string{c.Info.Name.O}, colRanges, "Column Stats", uint64(result))
 	}
 	return result, errors.Trace(err)
 }
 
 // GetRowCountByIndexRanges estimates the row count by a slice of Range.
-func (coll *HistColl) GetRowCountByIndexRanges(sc *stmtctx.StatementContext, idxID int64, indexRanges []*ranger.Range) (float64, error) {
+func (coll *HistColl) GetRowCountByIndexRanges(sctx sessionctx.Context, idxID int64, indexRanges []*ranger.Range) (float64, error) {
+	sc := sctx.GetSessionVars().StmtCtx
 	idx, ok := coll.Indices[idxID]
 	colNames := make([]string, 0, 8)
 	if ok {
@@ -396,28 +400,29 @@ func (coll *HistColl) GetRowCountByIndexRanges(sc *stmtctx.StatementContext, idx
 		}
 		result, err := getPseudoRowCountByIndexRanges(sc, indexRanges, float64(coll.Count), colsLen)
 		if err == nil && sc.EnableOptimizerCETrace && ok {
-			CETraceRange(sc, coll.PhysicalID, colNames, indexRanges, "Index Stats-Pseudo", uint64(result))
+			CETraceRange(sctx, coll.PhysicalID, colNames, indexRanges, "Index Stats-Pseudo", uint64(result))
 		}
 		return result, err
 	}
 	var result float64
 	var err error
 	if idx.CMSketch != nil && idx.StatsVer == Version1 {
-		result, err = coll.getIndexRowCount(sc, idxID, indexRanges)
+		result, err = coll.getIndexRowCount(sctx, idxID, indexRanges)
 	} else {
-		result, err = idx.GetRowCount(sc, coll, indexRanges, coll.Count)
+		result, err = idx.GetRowCount(sctx, coll, indexRanges, coll.Count)
 	}
 	if sc.EnableOptimizerCETrace {
-		CETraceRange(sc, coll.PhysicalID, colNames, indexRanges, "Index Stats", uint64(result))
+		CETraceRange(sctx, coll.PhysicalID, colNames, indexRanges, "Index Stats", uint64(result))
 	}
 	return result, errors.Trace(err)
 }
 
 // CETraceRange appends a list of ranges and related information into CE trace
-func CETraceRange(sc *stmtctx.StatementContext, tableID int64, colNames []string, ranges []*ranger.Range, tp string, rowCount uint64) {
+func CETraceRange(sctx sessionctx.Context, tableID int64, colNames []string, ranges []*ranger.Range, tp string, rowCount uint64) {
+	sc := sctx.GetSessionVars().StmtCtx
 	allPoint := true
 	for _, ran := range ranges {
-		if !ran.IsPointNullable(sc) {
+		if !ran.IsPointNullable(sctx) {
 			allPoint = false
 			break
 		}
@@ -572,7 +577,7 @@ func outOfRangeEQSelectivity(ndv, realtimeRowCount, columnRowCount int64) float6
 }
 
 // crossValidationSelectivity gets the selectivity of multi-column equal conditions by cross validation.
-func (coll *HistColl) crossValidationSelectivity(sc *stmtctx.StatementContext, idx *Index, usedColsLen int, idxPointRange *ranger.Range) (float64, float64, error) {
+func (coll *HistColl) crossValidationSelectivity(sctx sessionctx.Context, idx *Index, usedColsLen int, idxPointRange *ranger.Range) (float64, float64, error) {
 	minRowCount := math.MaxFloat64
 	cols := coll.Idx2ColumnIDs[idx.ID]
 	crossValidationSelectivity := 1.0
@@ -582,7 +587,7 @@ func (coll *HistColl) crossValidationSelectivity(sc *stmtctx.StatementContext, i
 			break
 		}
 		if col, ok := coll.Columns[colID]; ok {
-			if col.IsInvalid(sc, coll.Pseudo) {
+			if col.IsInvalid(sctx, coll.Pseudo) {
 				continue
 			}
 			lowExclude := idxPointRange.LowExclude
@@ -604,7 +609,7 @@ func (coll *HistColl) crossValidationSelectivity(sc *stmtctx.StatementContext, i
 				HighExclude: highExclude,
 			}
 
-			rowCount, err := col.GetColumnRowCount(sc, []*ranger.Range{&rang}, coll.Count, col.IsHandle)
+			rowCount, err := col.GetColumnRowCount(sctx, []*ranger.Range{&rang}, coll.Count, col.IsHandle)
 			if err != nil {
 				return 0, 0, err
 			}
@@ -619,7 +624,7 @@ func (coll *HistColl) crossValidationSelectivity(sc *stmtctx.StatementContext, i
 }
 
 // getEqualCondSelectivity gets the selectivity of the equal conditions.
-func (coll *HistColl) getEqualCondSelectivity(sc *stmtctx.StatementContext, idx *Index, bytes []byte, usedColsLen int, idxPointRange *ranger.Range) (float64, error) {
+func (coll *HistColl) getEqualCondSelectivity(sctx sessionctx.Context, idx *Index, bytes []byte, usedColsLen int, idxPointRange *ranger.Range) (float64, error) {
 	coverAll := len(idx.Info.Columns) == usedColsLen
 	// In this case, the row count is at most 1.
 	if idx.Info.Unique && coverAll {
@@ -646,7 +651,7 @@ func (coll *HistColl) getEqualCondSelectivity(sc *stmtctx.StatementContext, idx
 		return outOfRangeEQSelectivity(ndv, coll.Count, int64(idx.TotalRowCount())), nil
 	}
 
-	minRowCount, crossValidationSelectivity, err := coll.crossValidationSelectivity(sc, idx, usedColsLen, idxPointRange)
+	minRowCount, crossValidationSelectivity, err := coll.crossValidationSelectivity(sctx, idx, usedColsLen, idxPointRange)
 	if err != nil {
 		return 0, nil
 	}
@@ -658,7 +663,8 @@ func (coll *HistColl) getEqualCondSelectivity(sc *stmtctx.StatementContext, idx
 	return idxCount / idx.TotalRowCount(), nil
 }
 
-func (coll *HistColl) getIndexRowCount(sc *stmtctx.StatementContext, idxID int64, indexRanges []*ranger.Range) (float64, error) {
+func (coll *HistColl) getIndexRowCount(sctx sessionctx.Context, idxID int64, indexRanges []*ranger.Range) (float64, error) {
+	sc := sctx.GetSessionVars().StmtCtx
 	idx := coll.Indices[idxID]
 	totalCount := float64(0)
 	for _, ran := range indexRanges {
@@ -675,7 +681,7 @@ func (coll *HistColl) getIndexRowCount(sc *stmtctx.StatementContext, idxID int64
 		// on single-column index, use previous way as well, because CMSketch does not contain null
 		// values in this case.
 		if rangePosition == 0 || isSingleColIdxNullRange(idx, ran) {
-			count, err := idx.GetRowCount(sc, nil, []*ranger.Range{ran}, coll.Count)
+			count, err := idx.GetRowCount(sctx, nil, []*ranger.Range{ran}, coll.Count)
 			if err != nil {
 				return 0, errors.Trace(err)
 			}
@@ -689,7 +695,7 @@ func (coll *HistColl) getIndexRowCount(sc *stmtctx.StatementContext, idxID int64
 			if err != nil {
 				return 0, errors.Trace(err)
 			}
-			selectivity, err = coll.getEqualCondSelectivity(sc, idx, bytes, rangePosition, ran)
+			selectivity, err = coll.getEqualCondSelectivity(sctx, idx, bytes, rangePosition, ran)
 			if err != nil {
 				return 0, errors.Trace(err)
 			}
@@ -705,7 +711,7 @@ func (coll *HistColl) getIndexRowCount(sc *stmtctx.StatementContext, idxID int64
 				if err != nil {
 					return 0, err
 				}
-				res, err := coll.getEqualCondSelectivity(sc, idx, bytes, rangePosition, ran)
+				res, err := coll.getEqualCondSelectivity(sctx, idx, bytes, rangePosition, ran)
 				if err != nil {
 					return 0, errors.Trace(err)
 				}
@@ -731,9 +737,9 @@ func (coll *HistColl) getIndexRowCount(sc *stmtctx.StatementContext, idxID int64
 			}
 			// prefer index stats over column stats
 			if idx, ok := coll.ColID2IdxID[colID]; ok {
-				count, err = coll.GetRowCountByIndexRanges(sc, idx, []*ranger.Range{&rang})
+				count, err = coll.GetRowCountByIndexRanges(sctx, idx, []*ranger.Range{&rang})
 			} else {
-				count, err = coll.GetRowCountByColumnRanges(sc, colID, []*ranger.Range{&rang})
+				count, err = coll.GetRowCountByColumnRanges(sctx, colID, []*ranger.Range{&rang})
 			}
 			if err != nil {
 				return 0, errors.Trace(err)
diff --git a/store/copr/batch_coprocessor_test.go b/store/copr/batch_coprocessor_test.go
index 360cb54238685..97428319ab2b1 100644
--- a/store/copr/batch_coprocessor_test.go
+++ b/store/copr/batch_coprocessor_test.go
@@ -94,8 +94,6 @@ func calcReginCount(tasks []*batchCopTask) int {
 }
 
 func TestBalanceBatchCopTaskWithContinuity(t *testing.T) {
-	t.Parallel()
-
 	for replicaNum := 1; replicaNum < 6; replicaNum++ {
 		storeCount := 10
 		regionCount := 100000
diff --git a/store/copr/coprocessor_cache_test.go b/store/copr/coprocessor_cache_test.go
index 712d7b2e25ecf..8c68888ee61a8 100644
--- a/store/copr/coprocessor_cache_test.go
+++ b/store/copr/coprocessor_cache_test.go
@@ -25,7 +25,6 @@ import (
 )
 
 func TestBuildCacheKey(t *testing.T) {
-	t.Parallel()
 	req := coprocessor.Request{
 		Tp:      0xAB,
 		StartTs: 0xAABBCC,
@@ -70,7 +69,6 @@ func TestBuildCacheKey(t *testing.T) {
 }
 
 func TestDisable(t *testing.T) {
-	t.Parallel()
 	cache, err := newCoprCache(&config.CoprocessorCache{CapacityMB: 0})
 	require.NoError(t, err)
 	require.Nil(t, cache)
@@ -95,7 +93,6 @@ func TestDisable(t *testing.T) {
 }
 
 func TestAdmission(t *testing.T) {
-	t.Parallel()
 	cache, err := newCoprCache(&config.CoprocessorCache{AdmissionMinProcessMs: 5, AdmissionMaxResultMB: 1, CapacityMB: 1})
 	require.NoError(t, err)
 	require.NotNil(t, cache)
@@ -153,7 +150,6 @@ func TestAdmission(t *testing.T) {
 }
 
 func TestCacheValueLen(t *testing.T) {
-	t.Parallel()
 	v := coprCacheValue{
 		TimeStamp:         0x123,
 		RegionID:          0x1,
@@ -173,7 +169,6 @@ func TestCacheValueLen(t *testing.T) {
 }
 
 func TestGetSet(t *testing.T) {
-	t.Parallel()
 	cache, err := newCoprCache(&config.CoprocessorCache{AdmissionMinProcessMs: 5, AdmissionMaxResultMB: 1, CapacityMB: 1})
 	require.NoError(t, err)
 	require.NotNil(t, cache)
@@ -200,7 +195,6 @@ func TestGetSet(t *testing.T) {
 }
 
 func TestIssue24118(t *testing.T) {
-	t.Parallel()
 	_, err := newCoprCache(&config.CoprocessorCache{AdmissionMinProcessMs: 5, AdmissionMaxResultMB: 1, CapacityMB: -1})
 	require.EqualError(t, err, "Capacity must be > 0 to enable the cache")
 }
diff --git a/store/copr/coprocessor_test.go b/store/copr/coprocessor_test.go
index 15d8ac069dd5e..88ad5568f68eb 100644
--- a/store/copr/coprocessor_test.go
+++ b/store/copr/coprocessor_test.go
@@ -27,7 +27,6 @@ import (
 )
 
 func TestBuildTasks(t *testing.T) {
-	t.Parallel()
 	// nil --- 'g' --- 'n' --- 't' --- nil
 	// <-  0  -> <- 1 -> <- 2 -> <- 3 ->
 	mockClient, cluster, pdClient, err := testutils.NewMockTiKV("", nil)
@@ -155,7 +154,6 @@ func TestBuildTasks(t *testing.T) {
 }
 
 func TestSplitRegionRanges(t *testing.T) {
-	t.Parallel()
 	// nil --- 'g' --- 'n' --- 't' --- nil
 	// <-  0  -> <- 1 -> <- 2 -> <- 3 ->
 	mockClient, cluster, pdClient, err := testutils.NewMockTiKV("", nil)
@@ -218,7 +216,6 @@ func TestSplitRegionRanges(t *testing.T) {
 }
 
 func TestRebuild(t *testing.T) {
-	t.Parallel()
 	// nil --- 'm' --- nil
 	// <-  0  -> <- 1 ->
 	mockClient, cluster, pdClient, err := testutils.NewMockTiKV("", nil)
@@ -292,7 +289,6 @@ func rangeEqual(t *testing.T, ranges []kv.KeyRange, keys ...string) {
 }
 
 func TestBuildPagingTasks(t *testing.T) {
-	t.Parallel()
 	// nil --- 'g' --- 'n' --- 't' --- nil
 	// <-  0  -> <- 1 -> <- 2 -> <- 3 ->
 	mockClient, cluster, pdClient, err := testutils.NewMockTiKV("", nil)
@@ -345,7 +341,6 @@ func toRange(r *KeyRanges) []kv.KeyRange {
 }
 
 func TestCalculateRetry(t *testing.T) {
-	t.Parallel()
 	worker := copIteratorWorker{}
 
 	// split in one range
@@ -404,7 +399,6 @@ func TestCalculateRetry(t *testing.T) {
 }
 
 func TestCalculateRemain(t *testing.T) {
-	t.Parallel()
 	worker := copIteratorWorker{}
 
 	// split in one range
diff --git a/store/copr/key_ranges_test.go b/store/copr/key_ranges_test.go
index f26652c87175f..d2be4676dd589 100644
--- a/store/copr/key_ranges_test.go
+++ b/store/copr/key_ranges_test.go
@@ -22,7 +22,6 @@ import (
 )
 
 func TestCopRanges(t *testing.T) {
-	t.Parallel()
 	ranges := []kv.KeyRange{
 		{StartKey: []byte("a"), EndKey: []byte("b")},
 		{StartKey: []byte("c"), EndKey: []byte("d")},
@@ -36,7 +35,6 @@ func TestCopRanges(t *testing.T) {
 }
 
 func TestCopRangeSplit(t *testing.T) {
-	t.Parallel()
 	first := &kv.KeyRange{StartKey: []byte("a"), EndKey: []byte("b")}
 	mid := []kv.KeyRange{
 		{StartKey: []byte("c"), EndKey: []byte("d")},
diff --git a/store/driver/txn/batch_getter_test.go b/store/driver/txn/batch_getter_test.go
index d9e7b66d3c65a..2da439a49ed5c 100644
--- a/store/driver/txn/batch_getter_test.go
+++ b/store/driver/txn/batch_getter_test.go
@@ -22,8 +22,6 @@ import (
 )
 
 func TestBufferBatchGetter(t *testing.T) {
-	t.Parallel()
-
 	snap := newMockStore()
 	ka := []byte("a")
 	kb := []byte("b")
diff --git a/store/driver/txn/driver_test.go b/store/driver/txn/driver_test.go
index c60558ce11778..2a820e07bc03a 100644
--- a/store/driver/txn/driver_test.go
+++ b/store/driver/txn/driver_test.go
@@ -22,7 +22,6 @@ import (
 )
 
 func TestLockNotFoundPrint(t *testing.T) {
-	t.Parallel()
 	msg := "Txn(Mvcc(TxnLockNotFound { start_ts: 408090278408224772, commit_ts: 408090279311835140, " +
 		"key: [116, 128, 0, 0, 0, 0, 0, 50, 137, 95, 105, 128, 0, 0, 0, 0,0 ,0, 1, 1, 67, 49, 57, 48, 57, 50, 57, 48, 255, 48, 48, 48, 48, 48, 52, 56, 54, 255, 50, 53, 53, 50, 51, 0, 0, 0, 252] }))"
 	key := prettyLockNotFoundKey(msg)
@@ -31,7 +30,6 @@ func TestLockNotFoundPrint(t *testing.T) {
 }
 
 func TestWriteConflictPrettyFormat(t *testing.T) {
-	t.Parallel()
 	conflict := &kvrpcpb.WriteConflict{
 		StartTs:          399402937522847774,
 		ConflictTs:       399402937719455772,
diff --git a/store/driver/txn/union_iter_test.go b/store/driver/txn/union_iter_test.go
index ee0df5f596edd..abbe6031e6bdb 100644
--- a/store/driver/txn/union_iter_test.go
+++ b/store/driver/txn/union_iter_test.go
@@ -34,7 +34,6 @@ func r(key, value string) *kv.Entry {
 }
 
 func TestUnionIter(t *testing.T) {
-	t.Parallel()
 	// test iter normal cases, snap iter become invalid before dirty iter
 	snapRecords := []*kv.Entry{
 		r("k00", "v0"),
@@ -115,7 +114,6 @@ func TestUnionIter(t *testing.T) {
 }
 
 func TestUnionIterErrors(t *testing.T) {
-	t.Parallel()
 	cases := []struct {
 		dirty                     []*kv.Entry
 		snap                      []*kv.Entry
diff --git a/store/helper/helper_test.go b/store/helper/helper_test.go
index 7237b0b815db5..3640b4f479cef 100644
--- a/store/helper/helper_test.go
+++ b/store/helper/helper_test.go
@@ -34,8 +34,6 @@ import (
 )
 
 func TestHotRegion(t *testing.T) {
-	t.Parallel()
-
 	store, clean := createMockStore(t)
 	defer clean()
 
@@ -71,8 +69,6 @@ func TestHotRegion(t *testing.T) {
 }
 
 func TestGetRegionsTableInfo(t *testing.T) {
-	t.Parallel()
-
 	store, clean := createMockStore(t)
 	defer clean()
 
@@ -84,8 +80,6 @@ func TestGetRegionsTableInfo(t *testing.T) {
 }
 
 func TestTiKVRegionsInfo(t *testing.T) {
-	t.Parallel()
-
 	store, clean := createMockStore(t)
 	defer clean()
 
@@ -99,8 +93,6 @@ func TestTiKVRegionsInfo(t *testing.T) {
 }
 
 func TestTiKVStoresStat(t *testing.T) {
-	t.Parallel()
-
 	store, clean := createMockStore(t)
 	defer clean()
 
diff --git a/store/mockstore/mockcopr/cop_handler_dag_test.go b/store/mockstore/mockcopr/cop_handler_dag_test.go
index 1ce9922091966..5b11a668b854c 100644
--- a/store/mockstore/mockcopr/cop_handler_dag_test.go
+++ b/store/mockstore/mockcopr/cop_handler_dag_test.go
@@ -22,8 +22,6 @@ import (
 )
 
 func TestConstructTimezone(t *testing.T) {
-	t.Parallel()
-
 	secondsEastOfUTC := int((8 * time.Hour).Seconds())
 	loc, err := constructTimeZone("", secondsEastOfUTC)
 	require.NoError(t, err)
diff --git a/store/mockstore/mockcopr/executor_test.go b/store/mockstore/mockcopr/executor_test.go
index 2fe82a996357b..af75c322e6fd6 100644
--- a/store/mockstore/mockcopr/executor_test.go
+++ b/store/mockstore/mockcopr/executor_test.go
@@ -37,8 +37,6 @@ import (
 // This test checks the resolve lock functionality. When a txn meets the lock of a large transaction,
 // it should not block by the lock.
 func TestResolvedLargeTxnLocks(t *testing.T) {
-	t.Parallel()
-
 	rpcClient, cluster, pdClient, err := testutils.NewMockTiKV("", mockcopr.NewCoprRPCHandler())
 	require.NoError(t, err)
 
@@ -105,8 +103,6 @@ func TestResolvedLargeTxnLocks(t *testing.T) {
 }
 
 func TestIssue15662(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 	tk := testkit.NewTestKit(t, store)
diff --git a/store/mockstore/unistore/cophandler/cop_handler_test.go b/store/mockstore/unistore/cophandler/cop_handler_test.go
index 4e8462c8be651..fd4e244344f6f 100644
--- a/store/mockstore/unistore/cophandler/cop_handler_test.go
+++ b/store/mockstore/unistore/cophandler/cop_handler_test.go
@@ -279,8 +279,6 @@ func (dagBuilder *dagBuilder) build() *tipb.DAGRequest {
 
 // see tikv/src/coprocessor/util.rs for more detail
 func TestIsPrefixNext(t *testing.T) {
-	t.Parallel()
-
 	require.True(t, isPrefixNext([]byte{}, []byte{0}))
 	require.True(t, isPrefixNext([]byte{0}, []byte{1}))
 	require.True(t, isPrefixNext([]byte{1}, []byte{2}))
@@ -295,8 +293,6 @@ func TestIsPrefixNext(t *testing.T) {
 }
 
 func TestPointGet(t *testing.T) {
-	t.Parallel()
-
 	// here would build mvccStore and server, and prepare
 	// three rows data, just like the test data of table_scan.rs.
 	// then init the store with the generated data.
@@ -349,8 +345,6 @@ func TestPointGet(t *testing.T) {
 }
 
 func TestClosureExecutor(t *testing.T) {
-	t.Parallel()
-
 	data := prepareTestTableData(t, keyNumber, tableID)
 	store, clean := newTestStore(t, "cop_handler_test_db", "cop_handler_test_log")
 	defer clean()
diff --git a/store/mockstore/unistore/lockstore/lockstore_test.go b/store/mockstore/unistore/lockstore/lockstore_test.go
index 8161f7eef1c1f..44a271f070653 100644
--- a/store/mockstore/unistore/lockstore/lockstore_test.go
+++ b/store/mockstore/unistore/lockstore/lockstore_test.go
@@ -26,8 +26,6 @@ import (
 )
 
 func TestMemStore(t *testing.T) {
-	t.Parallel()
-
 	prefix := "ls"
 	n := 30000
 	ls := NewMemStore(1 << 10)
@@ -80,8 +78,6 @@ func deleteMemStore(t *testing.T, ls *MemStore, prefix string, n int) {
 }
 
 func TestIterator(t *testing.T) {
-	t.Parallel()
-
 	_ = checkKey
 	t.Skip("Skip this unstable test(#26235) and bring it back before 2021-07-29.")
 	ls := NewMemStore(1 << 10)
@@ -133,8 +129,6 @@ func numToKey(n int) []byte {
 }
 
 func TestReplace(t *testing.T) {
-	t.Parallel()
-
 	prefix := "ls"
 	n := 30000
 	ls := NewMemStore(1 << 10)
diff --git a/store/mockstore/unistore/raw_handler_test.go b/store/mockstore/unistore/raw_handler_test.go
index 0f56a8d499bff..a235331500240 100644
--- a/store/mockstore/unistore/raw_handler_test.go
+++ b/store/mockstore/unistore/raw_handler_test.go
@@ -25,8 +25,6 @@ import (
 )
 
 func TestRawHandler(t *testing.T) {
-	t.Parallel()
-
 	h := newRawHandler()
 	ctx := context.Background()
 	keys := make([][]byte, 10)
diff --git a/store/mockstore/unistore/tikv/detector_test.go b/store/mockstore/unistore/tikv/detector_test.go
index 0ccbf3ec450bf..e44b5ca1fc0f1 100644
--- a/store/mockstore/unistore/tikv/detector_test.go
+++ b/store/mockstore/unistore/tikv/detector_test.go
@@ -36,8 +36,6 @@ import (
 )
 
 func TestDeadlock(t *testing.T) {
-	t.Parallel()
-
 	makeDiagCtx := func(key string, resourceGroupTag string) diagnosticContext {
 		return diagnosticContext{
 			key:              []byte(key),
diff --git a/store/mockstore/unistore/tikv/mvcc_test.go b/store/mockstore/unistore/tikv/mvcc_test.go
index f9d681511ced4..b08162437ab6c 100644
--- a/store/mockstore/unistore/tikv/mvcc_test.go
+++ b/store/mockstore/unistore/tikv/mvcc_test.go
@@ -483,7 +483,6 @@ func MustGetRollback(key []byte, ts uint64, store *TestStore) {
 }
 
 func TestBasicOptimistic(t *testing.T) {
-	t.Parallel()
 	store, close := NewTestStore("basic_optimistic_db", "basic_optimistic_log", t)
 	defer close()
 
@@ -498,7 +497,6 @@ func TestBasicOptimistic(t *testing.T) {
 }
 
 func TestPessimiticTxnTTL(t *testing.T) {
-	t.Parallel()
 	var err error
 	store, close := NewTestStore("basic_optimistic_db", "basic_optimistic_log", t)
 	defer close()
@@ -528,7 +526,6 @@ func TestPessimiticTxnTTL(t *testing.T) {
 }
 
 func TestRollback(t *testing.T) {
-	t.Parallel()
 	store, close := NewTestStore("basic_optimistic_db", "basic_optimistic_log", t)
 	defer close()
 
@@ -563,7 +560,6 @@ func TestRollback(t *testing.T) {
 }
 
 func TestOverwritePessimisitcLock(t *testing.T) {
-	t.Parallel()
 	var err error
 	store, close := NewTestStore("basic_optimistic_db", "basic_optimistic_log", t)
 	defer close()
@@ -592,7 +588,6 @@ func TestOverwritePessimisitcLock(t *testing.T) {
 }
 
 func TestCheckTxnStatus(t *testing.T) {
-	t.Parallel()
 	var err error
 	store, close := NewTestStore("basic_optimistic_db", "basic_optimistic_log", t)
 	defer close()
@@ -695,7 +690,6 @@ func TestCheckTxnStatus(t *testing.T) {
 }
 
 func TestCheckSecondaryLocksStatus(t *testing.T) {
-	t.Parallel()
 	store, close := NewTestStore("basic_optimistic_db", "basic_optimistic_log", t)
 	defer close()
 
@@ -762,7 +756,6 @@ func TestCheckSecondaryLocksStatus(t *testing.T) {
 }
 
 func TestMvccGet(t *testing.T) {
-	t.Parallel()
 	var err error
 	store, close := NewTestStore("basic_optimistic_db", "basic_optimistic_log", t)
 	defer close()
@@ -877,7 +870,6 @@ func TestMvccGet(t *testing.T) {
 }
 
 func TestPrimaryKeyOpLock(t *testing.T) {
-	t.Parallel()
 	store, close := NewTestStore("basic_optimistic_db", "basic_optimistic_log", t)
 	defer close()
 
@@ -929,7 +921,6 @@ func TestPrimaryKeyOpLock(t *testing.T) {
 }
 
 func TestMvccTxnRead(t *testing.T) {
-	t.Parallel()
 	store, close := NewTestStore("basic_optimistic_db", "basic_optimistic_log", t)
 	defer close()
 
@@ -1001,7 +992,6 @@ func TestMvccTxnRead(t *testing.T) {
 }
 
 func TestTxnPrewrite(t *testing.T) {
-	t.Parallel()
 	store, close := NewTestStore("basic_optimistic_db", "basic_optimistic_log", t)
 	defer close()
 
@@ -1037,7 +1027,6 @@ func TestTxnPrewrite(t *testing.T) {
 }
 
 func TestPrewriteInsert(t *testing.T) {
-	t.Parallel()
 	store, close := NewTestStore("basic_optimistic_db", "basic_optimistic_log", t)
 	defer close()
 
@@ -1074,7 +1063,6 @@ func TestPrewriteInsert(t *testing.T) {
 }
 
 func TestRollbackKey(t *testing.T) {
-	t.Parallel()
 	store, close := NewTestStore("basic_optimistic_db", "basic_optimistic_log", t)
 	defer close()
 
@@ -1100,7 +1088,6 @@ func TestRollbackKey(t *testing.T) {
 }
 
 func TestCleanup(t *testing.T) {
-	t.Parallel()
 	store, close := NewTestStore("basic_optimistic_db", "basic_optimistic_log", t)
 	defer close()
 
@@ -1123,7 +1110,6 @@ func TestCleanup(t *testing.T) {
 }
 
 func TestCommit(t *testing.T) {
-	t.Parallel()
 	store, close := NewTestStore("basic_optimistic_db", "basic_optimistic_log", t)
 	defer close()
 
@@ -1175,7 +1161,6 @@ func TestCommit(t *testing.T) {
 }
 
 func TestMinCommitTs(t *testing.T) {
-	t.Parallel()
 	store, close := NewTestStore("basic_optimistic_db", "basic_optimistic_log", t)
 	defer close()
 
@@ -1197,7 +1182,6 @@ func TestMinCommitTs(t *testing.T) {
 }
 
 func TestPessimisticLock(t *testing.T) {
-	t.Parallel()
 	store, close := NewTestStore("basic_optimistic_db", "basic_optimistic_log", t)
 	defer close()
 
@@ -1363,7 +1347,6 @@ func TestPessimisticLock(t *testing.T) {
 }
 
 func TestResolveCommit(t *testing.T) {
-	t.Parallel()
 	store, close := NewTestStore("basic_optimistic_db", "basic_optimistic_log", t)
 	defer close()
 
@@ -1429,7 +1412,6 @@ func MustLoad(startTS, commitTS uint64, store *TestStore, pairs ...string) {
 }
 
 func TestBatchGet(t *testing.T) {
-	t.Parallel()
 	store, close := NewTestStore("basic_optimistic_db", "basic_optimistic_log", t)
 	defer close()
 	MustLoad(100, 101, store, "ta:1", "tb:2", "tc:3")
@@ -1443,7 +1425,6 @@ func TestBatchGet(t *testing.T) {
 }
 
 func TestCommitPessimisticLock(t *testing.T) {
-	t.Parallel()
 	store, close := NewTestStore("basic_optimistic_db", "basic_optimistic_log", t)
 	defer close()
 	k := []byte("ta")
@@ -1454,7 +1435,6 @@ func TestCommitPessimisticLock(t *testing.T) {
 }
 
 func TestOpCheckNotExist(t *testing.T) {
-	t.Parallel()
 	store, close := NewTestStore("basic_optimistic_db", "basic_optimistic_log", t)
 	defer close()
 
@@ -1472,7 +1452,6 @@ func TestOpCheckNotExist(t *testing.T) {
 }
 
 func TestPessimisticLockForce(t *testing.T) {
-	t.Parallel()
 	store, close := NewTestStore("basic_optimistic_db", "basic_optimistic_log", t)
 	defer close()
 
@@ -1490,7 +1469,6 @@ func TestPessimisticLockForce(t *testing.T) {
 }
 
 func TestScanSampleStep(t *testing.T) {
-	t.Parallel()
 	store, close := NewTestStore("basic_optimistic_db", "basic_optimistic_log", t)
 	defer close()
 	for i := 0; i < 1000; i++ {
@@ -1524,7 +1502,6 @@ func genScanSampleStepKey(i int) []byte {
 }
 
 func TestAsyncCommitPrewrite(t *testing.T) {
-	t.Parallel()
 	store, close := NewTestStore("basic_optimistic_db", "basic_optimistic_log", t)
 	defer close()
 
@@ -1554,7 +1531,6 @@ func TestAsyncCommitPrewrite(t *testing.T) {
 }
 
 func TestAccessCommittedLocks(t *testing.T) {
-	t.Parallel()
 	store, close := NewTestStore("basic_optimistic_db", "basic_optimistic_log", t)
 	defer close()
 
diff --git a/store/mockstore/unistore/util/lockwaiter/lockwaiter_test.go b/store/mockstore/unistore/util/lockwaiter/lockwaiter_test.go
index be89f8184bc64..96fb02d8cf6c1 100644
--- a/store/mockstore/unistore/util/lockwaiter/lockwaiter_test.go
+++ b/store/mockstore/unistore/util/lockwaiter/lockwaiter_test.go
@@ -26,8 +26,6 @@ import (
 )
 
 func TestLockwaiterBasic(t *testing.T) {
-	t.Parallel()
-
 	mgr := NewManager(&config.DefaultConf)
 
 	keyHash := uint64(100)
diff --git a/store/store_test.go b/store/store_test.go
index c02f87f312d93..2bad71202729b 100644
--- a/store/store_test.go
+++ b/store/store_test.go
@@ -141,8 +141,6 @@ func TestNew(t *testing.T) {
 }
 
 func TestGetSet(t *testing.T) {
-	t.Parallel()
-
 	store, err := mockstore.NewMockStore()
 	require.NoError(t, err)
 	defer func() {
@@ -198,8 +196,6 @@ func TestSeek(t *testing.T) {
 }
 
 func TestInc(t *testing.T) {
-	t.Parallel()
-
 	store, err := mockstore.NewMockStore()
 	require.NoError(t, err)
 	defer func() {
@@ -240,8 +236,6 @@ func TestInc(t *testing.T) {
 }
 
 func TestDelete(t *testing.T) {
-	t.Parallel()
-
 	store, err := mockstore.NewMockStore()
 	require.NoError(t, err)
 	defer func() {
@@ -287,8 +281,6 @@ func TestDelete(t *testing.T) {
 }
 
 func TestDelete2(t *testing.T) {
-	t.Parallel()
-
 	store, err := mockstore.NewMockStore()
 	require.NoError(t, err)
 	defer func() {
@@ -329,8 +321,6 @@ func TestDelete2(t *testing.T) {
 }
 
 func TestSetNil(t *testing.T) {
-	t.Parallel()
-
 	store, err := mockstore.NewMockStore()
 	require.NoError(t, err)
 	defer func() {
@@ -347,8 +337,6 @@ func TestSetNil(t *testing.T) {
 }
 
 func TestBasicSeek(t *testing.T) {
-	t.Parallel()
-
 	store, err := mockstore.NewMockStore()
 	require.NoError(t, err)
 	defer func() {
@@ -373,8 +361,6 @@ func TestBasicSeek(t *testing.T) {
 }
 
 func TestBasicTable(t *testing.T) {
-	t.Parallel()
-
 	store, err := mockstore.NewMockStore()
 	require.NoError(t, err)
 	defer func() {
@@ -431,8 +417,6 @@ func TestBasicTable(t *testing.T) {
 }
 
 func TestRollback(t *testing.T) {
-	t.Parallel()
-
 	store, err := mockstore.NewMockStore()
 	require.NoError(t, err)
 	defer func() {
@@ -468,8 +452,6 @@ func TestRollback(t *testing.T) {
 }
 
 func TestSeekMin(t *testing.T) {
-	t.Parallel()
-
 	store, err := mockstore.NewMockStore()
 	require.NoError(t, err)
 	defer func() {
@@ -510,8 +492,6 @@ func TestSeekMin(t *testing.T) {
 }
 
 func TestConditionIfNotExist(t *testing.T) {
-	t.Parallel()
-
 	store, err := mockstore.NewMockStore()
 	require.NoError(t, err)
 	defer func() {
@@ -552,8 +532,6 @@ func TestConditionIfNotExist(t *testing.T) {
 }
 
 func TestConditionIfEqual(t *testing.T) {
-	t.Parallel()
-
 	store, err := mockstore.NewMockStore()
 	require.NoError(t, err)
 	defer func() {
@@ -599,8 +577,6 @@ func TestConditionIfEqual(t *testing.T) {
 }
 
 func TestConditionUpdate(t *testing.T) {
-	t.Parallel()
-
 	store, err := mockstore.NewMockStore()
 	require.NoError(t, err)
 	defer func() {
@@ -659,8 +635,6 @@ func TestDBClose(t *testing.T) {
 }
 
 func TestIsolationInc(t *testing.T) {
-	t.Parallel()
-
 	store, err := mockstore.NewMockStore()
 	require.NoError(t, err)
 	defer func() {
@@ -707,8 +681,6 @@ func TestIsolationInc(t *testing.T) {
 }
 
 func TestIsolationMultiInc(t *testing.T) {
-	t.Parallel()
-
 	store, err := mockstore.NewMockStore()
 	require.NoError(t, err)
 	defer func() {
@@ -763,7 +735,6 @@ func TestIsolationMultiInc(t *testing.T) {
 }
 
 func TestRetryOpenStore(t *testing.T) {
-	t.Parallel()
 	begin := time.Now()
 	require.NoError(t, Register("dummy", &brokenStore{}))
 	store, err := newStoreWithRetry("dummy://dummy-store", 3)
@@ -778,7 +749,6 @@ func TestRetryOpenStore(t *testing.T) {
 }
 
 func TestOpenStore(t *testing.T) {
-	t.Parallel()
 	require.NoError(t, Register("open", &brokenStore{}))
 	store, err := newStoreWithRetry(":", 3)
 	if store != nil {
@@ -790,7 +760,6 @@ func TestOpenStore(t *testing.T) {
 }
 
 func TestRegister(t *testing.T) {
-	t.Parallel()
 	err := Register("retry", &brokenStore{})
 	require.NoError(t, err)
 	err = Register("retry", &brokenStore{})
diff --git a/table/column_test.go b/table/column_test.go
index 7c860feeae3d6..02cbb12237afc 100644
--- a/table/column_test.go
+++ b/table/column_test.go
@@ -33,7 +33,6 @@ import (
 )
 
 func TestString(t *testing.T) {
-	t.Parallel()
 	col := ToColumn(&model.ColumnInfo{
 		FieldType: *types.NewFieldType(mysql.TypeTiny),
 		State:     model.StatePublic,
@@ -84,7 +83,6 @@ func TestString(t *testing.T) {
 }
 
 func TestFind(t *testing.T) {
-	t.Parallel()
 	cols := []*Column{
 		newCol("a"),
 		newCol("b"),
@@ -104,7 +102,6 @@ func TestFind(t *testing.T) {
 }
 
 func TestCheck(t *testing.T) {
-	t.Parallel()
 	col := newCol("a")
 	col.Flag = mysql.AutoIncrementFlag
 	cols := []*Column{col, col}
@@ -121,7 +118,6 @@ func TestCheck(t *testing.T) {
 }
 
 func TestHandleBadNull(t *testing.T) {
-	t.Parallel()
 	col := newCol("a")
 	sc := new(stmtctx.StatementContext)
 	d := types.Datum{}
@@ -141,7 +137,6 @@ func TestHandleBadNull(t *testing.T) {
 }
 
 func TestDesc(t *testing.T) {
-	t.Parallel()
 	col := newCol("a")
 	col.Flag = mysql.AutoIncrementFlag | mysql.NotNullFlag | mysql.PriKeyFlag
 	NewColDesc(col)
@@ -252,7 +247,6 @@ func TestGetZeroValue(t *testing.T) {
 	sc := new(stmtctx.StatementContext)
 	for _, tt := range tests {
 		t.Run(fmt.Sprintf("%+v", tt.ft), func(t *testing.T) {
-			t.Parallel()
 			colInfo := &model.ColumnInfo{FieldType: *tt.ft}
 			zv := GetZeroValue(colInfo)
 			require.Equal(t, tt.value.Kind(), zv.Kind())
@@ -264,7 +258,6 @@ func TestGetZeroValue(t *testing.T) {
 }
 
 func TestCastValue(t *testing.T) {
-	t.Parallel()
 	ctx := mock.NewContext()
 	colInfo := model.ColumnInfo{
 		FieldType: *types.NewFieldType(mysql.TypeLong),
@@ -313,7 +306,6 @@ func TestCastValue(t *testing.T) {
 }
 
 func TestGetDefaultValue(t *testing.T) {
-	t.Parallel()
 	var nilDt types.Datum
 	nilDt.SetNull()
 	ctx := mock.NewContext()
diff --git a/table/table_test.go b/table/table_test.go
index ca5b845e97de9..3cc6f16c4fcdd 100644
--- a/table/table_test.go
+++ b/table/table_test.go
@@ -23,7 +23,6 @@ import (
 )
 
 func TestErrorCode(t *testing.T) {
-	t.Parallel()
 	require.Equal(t, mysql.ErrBadNull, int(terror.ToSQLError(ErrColumnCantNull).Code))
 	require.Equal(t, mysql.ErrBadField, int(terror.ToSQLError(ErrUnknownColumn).Code))
 	require.Equal(t, mysql.ErrFieldSpecifiedTwice, int(terror.ToSQLError(errDuplicateColumn).Code))
diff --git a/table/tables/index_test.go b/table/tables/index_test.go
index d2bfd075188d6..5678ce8b39b18 100644
--- a/table/tables/index_test.go
+++ b/table/tables/index_test.go
@@ -34,7 +34,6 @@ import (
 )
 
 func TestSingleColumnCommonHandle(t *testing.T) {
-	t.Parallel()
 	tblInfo := buildTableInfo(t, "create table t (a varchar(255) primary key, u int unique, nu int, index nu (nu))")
 	var idxUnique, idxNonUnique table.Index
 	for _, idxInfo := range tblInfo.Indices {
diff --git a/table/tables/partition_test.go b/table/tables/partition_test.go
index 7807746ed76ac..4d99301684fd3 100644
--- a/table/tables/partition_test.go
+++ b/table/tables/partition_test.go
@@ -31,7 +31,6 @@ import (
 )
 
 func TestPartitionBasic(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 	tk := testkit.NewTestKit(t, store)
@@ -63,7 +62,6 @@ PARTITION BY RANGE COLUMNS ( id ) (
 }
 
 func TestPartitionAddRecord(t *testing.T) {
-	t.Parallel()
 	createTable1 := `CREATE TABLE test.t1 (id int(11), index(id))
 PARTITION BY RANGE ( id ) (
 		PARTITION p0 VALUES LESS THAN (6),
@@ -166,7 +164,6 @@ PARTITION BY RANGE ( id ) (
 }
 
 func TestHashPartitionAddRecord(t *testing.T) {
-	t.Parallel()
 	store, dom, clean := testkit.CreateMockStoreAndDomain(t)
 	defer clean()
 	tk := testkit.NewTestKit(t, store)
@@ -236,7 +233,6 @@ func TestHashPartitionAddRecord(t *testing.T) {
 
 // TestPartitionGetPhysicalID tests partition.GetPhysicalID().
 func TestPartitionGetPhysicalID(t *testing.T) {
-	t.Parallel()
 	createTable1 := `CREATE TABLE test.t1 (id int(11), index(id))
 PARTITION BY RANGE ( id ) (
 		PARTITION p0 VALUES LESS THAN (6),
@@ -264,7 +260,6 @@ PARTITION BY RANGE ( id ) (
 }
 
 func TestGeneratePartitionExpr(t *testing.T) {
-	t.Parallel()
 	store, dom, clean := testkit.CreateMockStoreAndDomain(t)
 	defer clean()
 	tk := testkit.NewTestKit(t, store)
@@ -298,7 +293,6 @@ func TestGeneratePartitionExpr(t *testing.T) {
 }
 
 func TestLocateRangeColumnPartitionErr(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 	tk := testkit.NewTestKit(t, store)
@@ -317,7 +311,6 @@ func TestLocateRangeColumnPartitionErr(t *testing.T) {
 }
 
 func TestLocateRangePartitionErr(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 	tk := testkit.NewTestKit(t, store)
@@ -336,7 +329,6 @@ func TestLocateRangePartitionErr(t *testing.T) {
 }
 
 func TestLocatePartitionWithExtraHandle(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 	tk := testkit.NewTestKit(t, store)
@@ -356,7 +348,6 @@ func TestLocatePartitionWithExtraHandle(t *testing.T) {
 }
 
 func TestMultiTableUpdate(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 	tk := testkit.NewTestKit(t, store)
@@ -380,7 +371,6 @@ func TestMultiTableUpdate(t *testing.T) {
 }
 
 func TestLocatePartitionSingleColumn(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 	tk := testkit.NewTestKit(t, store)
@@ -411,7 +401,6 @@ func TestLocatePartitionSingleColumn(t *testing.T) {
 }
 
 func TestTimeZoneChange(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 	tk := testkit.NewTestKit(t, store)
@@ -471,7 +460,6 @@ func TestTimeZoneChange(t *testing.T) {
 }
 
 func TestCreatePartitionTableNotSupport(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 	tk := testkit.NewTestKit(t, store)
@@ -487,7 +475,6 @@ func TestCreatePartitionTableNotSupport(t *testing.T) {
 }
 
 func TestRangePartitionUnderNoUnsigned(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 	tk := testkit.NewTestKit(t, store)
@@ -513,7 +500,6 @@ func TestRangePartitionUnderNoUnsigned(t *testing.T) {
 }
 
 func TestIntUint(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 	tk := testkit.NewTestKit(t, store)
@@ -550,7 +536,6 @@ partition p4 values less than (9223372036854775806))`)
 }
 
 func TestHashPartitionAndConditionConflict(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 	tk := testkit.NewTestKit(t, store)
@@ -576,7 +561,6 @@ func TestHashPartitionAndConditionConflict(t *testing.T) {
 }
 
 func TestHashPartitionInsertValue(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 	tk := testkit.NewTestKit(t, store)
@@ -595,7 +579,6 @@ func TestHashPartitionInsertValue(t *testing.T) {
 }
 
 func TestIssue21574(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 	tk := testkit.NewTestKit(t, store)
@@ -609,7 +592,6 @@ func TestIssue21574(t *testing.T) {
 }
 
 func TestIssue24746(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 	tk := testkit.NewTestKit(t, store)
diff --git a/table/tables/state_remote_test.go b/table/tables/state_remote_test.go
index 227924d58c8db..b854388aef2c3 100644
--- a/table/tables/state_remote_test.go
+++ b/table/tables/state_remote_test.go
@@ -46,7 +46,6 @@ func initRow(ctx context.Context, exec session.Session, tid int) error {
 }
 
 func TestStateRemote(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 	tk := testkit.NewTestKit(t, store)
diff --git a/table/tables/tables_test.go b/table/tables/tables_test.go
index fdc5ef037402b..b093e96c6be38 100644
--- a/table/tables/tables_test.go
+++ b/table/tables/tables_test.go
@@ -82,7 +82,6 @@ func (m mockPumpClient) PullBinlogs(ctx context.Context, in *binlog.PullBinlogRe
 }
 
 func TestBasic(t *testing.T) {
-	t.Parallel()
 	store, dom, clean := testkit.CreateMockStoreAndDomain(t)
 	defer clean()
 	tk := testkit.NewTestKit(t, store)
@@ -183,7 +182,6 @@ func countEntriesWithPrefix(ctx sessionctx.Context, prefix []byte) (int, error)
 }
 
 func TestTypes(t *testing.T) {
-	t.Parallel()
 	ctx := context.Background()
 	store, dom, clean := testkit.CreateMockStoreAndDomain(t)
 	defer clean()
@@ -237,7 +235,6 @@ func TestTypes(t *testing.T) {
 }
 
 func TestUniqueIndexMultipleNullEntries(t *testing.T) {
-	t.Parallel()
 	ctx := context.Background()
 	store, dom, clean := testkit.CreateMockStoreAndDomain(t)
 	defer clean()
@@ -279,7 +276,6 @@ func TestUniqueIndexMultipleNullEntries(t *testing.T) {
 }
 
 func TestRowKeyCodec(t *testing.T) {
-	t.Parallel()
 	tableVal := []struct {
 		tableID int64
 		h       int64
@@ -321,7 +317,6 @@ func TestRowKeyCodec(t *testing.T) {
 }
 
 func TestUnsignedPK(t *testing.T) {
-	t.Parallel()
 	store, dom, clean := testkit.CreateMockStoreAndDomain(t)
 	defer clean()
 	tk := testkit.NewTestKit(t, store)
@@ -346,7 +341,6 @@ func TestUnsignedPK(t *testing.T) {
 }
 
 func TestIterRecords(t *testing.T) {
-	t.Parallel()
 	store, dom, clean := testkit.CreateMockStoreAndDomain(t)
 	defer clean()
 	tk := testkit.NewTestKit(t, store)
@@ -373,7 +367,6 @@ func TestIterRecords(t *testing.T) {
 }
 
 func TestTableFromMeta(t *testing.T) {
-	t.Parallel()
 	store, dom, clean := testkit.CreateMockStoreAndDomain(t)
 	defer clean()
 	tk := testkit.NewTestKit(t, store)
@@ -427,7 +420,6 @@ func TestTableFromMeta(t *testing.T) {
 }
 
 func TestShardRowIDBitsStep(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 	tk := testkit.NewTestKit(t, store)
@@ -447,7 +439,6 @@ func TestShardRowIDBitsStep(t *testing.T) {
 }
 
 func TestHiddenColumn(t *testing.T) {
-	t.Parallel()
 	store, dom, clean := testkit.CreateMockStoreAndDomain(t)
 	defer clean()
 	tk := testkit.NewTestKit(t, store)
@@ -615,7 +606,6 @@ func TestHiddenColumn(t *testing.T) {
 }
 
 func TestAddRecordWithCtx(t *testing.T) {
-	t.Parallel()
 	store, dom, clean := testkit.CreateMockStoreAndDomain(t)
 	defer clean()
 	tk := testkit.NewTestKit(t, store)
@@ -662,7 +652,6 @@ func TestAddRecordWithCtx(t *testing.T) {
 }
 
 func TestConstraintCheckForUniqueIndex(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 
 	tk := testkit.NewTestKit(t, store)
@@ -718,7 +707,6 @@ func TestConstraintCheckForUniqueIndex(t *testing.T) {
 }
 
 func TestViewColumns(t *testing.T) {
-	t.Parallel()
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 	tk := testkit.NewTestKit(t, store)
diff --git a/table/temptable/ddl_test.go b/table/temptable/ddl_test.go
index 2e56dd5e7ab1e..1418a35ad83d1 100644
--- a/table/temptable/ddl_test.go
+++ b/table/temptable/ddl_test.go
@@ -45,8 +45,6 @@ func createTestSuite(t *testing.T) (sessionctx.Context, *temporaryTableDDL, func
 }
 
 func TestAddLocalTemporaryTable(t *testing.T) {
-	t.Parallel()
-
 	sctx, ddl, clean := createTestSuite(t)
 	defer clean()
 
@@ -110,8 +108,6 @@ func TestAddLocalTemporaryTable(t *testing.T) {
 }
 
 func TestRemoveLocalTemporaryTable(t *testing.T) {
-	t.Parallel()
-
 	sctx, ddl, clean := createTestSuite(t)
 	defer clean()
 
@@ -159,8 +155,6 @@ func TestRemoveLocalTemporaryTable(t *testing.T) {
 }
 
 func TestTruncateLocalTemporaryTable(t *testing.T) {
-	t.Parallel()
-
 	sctx, ddl, clean := createTestSuite(t)
 	defer clean()
 
diff --git a/table/temptable/interceptor_test.go b/table/temptable/interceptor_test.go
index bb5b8868a753e..f75ea1bf0bd6d 100644
--- a/table/temptable/interceptor_test.go
+++ b/table/temptable/interceptor_test.go
@@ -49,7 +49,6 @@ func encodeTableKey(tblID int64, suffix ...byte) kv.Key {
 }
 
 func TestGetKeyAccessedTableID(t *testing.T) {
-	t.Parallel()
 	tbPrefix := tablecodec.TablePrefix()
 	prefix0 := encodeTableKey(0)
 	prefixMax := encodeTableKey(math.MaxInt64)
@@ -114,7 +113,6 @@ func TestGetKeyAccessedTableID(t *testing.T) {
 }
 
 func TestGetRangeAccessedTableID(t *testing.T) {
-	t.Parallel()
 	cases := []struct {
 		start kv.Key
 		end   kv.Key
@@ -219,7 +217,6 @@ func TestGetRangeAccessedTableID(t *testing.T) {
 }
 
 func TestNotTableRange(t *testing.T) {
-	t.Parallel()
 	falseCases := [][]kv.Key{
 		{nil, nil},
 		{nil, encodeTableKey(1, 0)},
@@ -254,7 +251,6 @@ func TestNotTableRange(t *testing.T) {
 }
 
 func TestGetSessionTemporaryTableKey(t *testing.T) {
-	t.Parallel()
 	localTempTableData := []*kv.Entry{
 		{Key: encodeTableKey(5), Value: []byte("v5")},
 		{Key: encodeTableKey(5, 0), Value: []byte("v50")},
@@ -331,7 +327,6 @@ func TestGetSessionTemporaryTableKey(t *testing.T) {
 }
 
 func TestInterceptorTemporaryTableInfoByID(t *testing.T) {
-	t.Parallel()
 	is := newMockedInfoSchema(t).
 		AddTable(model.TempTableNone, 1, 5).
 		AddTable(model.TempTableGlobal, 2, 6).
@@ -381,7 +376,6 @@ func TestInterceptorTemporaryTableInfoByID(t *testing.T) {
 }
 
 func TestInterceptorOnGet(t *testing.T) {
-	t.Parallel()
 	is := newMockedInfoSchema(t).
 		AddTable(model.TempTableNone, 1).
 		AddTable(model.TempTableGlobal, 3).
@@ -528,7 +522,6 @@ func TestInterceptorOnGet(t *testing.T) {
 }
 
 func TestInterceptorBatchGetTemporaryTableKeys(t *testing.T) {
-	t.Parallel()
 	localTempTableData := []*kv.Entry{
 		{Key: encodeTableKey(5), Value: []byte("v5")},
 		{Key: encodeTableKey(5, 0), Value: []byte("v50")},
@@ -712,7 +705,6 @@ func TestInterceptorBatchGetTemporaryTableKeys(t *testing.T) {
 }
 
 func TestInterceptorOnBatchGet(t *testing.T) {
-	t.Parallel()
 	is := newMockedInfoSchema(t).
 		AddTable(model.TempTableNone, 1).
 		AddTable(model.TempTableGlobal, 3).
@@ -914,7 +906,6 @@ func TestInterceptorOnBatchGet(t *testing.T) {
 }
 
 func TestCreateUnionIter(t *testing.T) {
-	t.Parallel()
 	retriever := newMockedRetriever(t).SetData([]*kv.Entry{
 		{Key: kv.Key("k1"), Value: []byte("v1")},
 		{Key: kv.Key("k10"), Value: []byte("")},
@@ -1055,7 +1046,6 @@ func TestCreateUnionIter(t *testing.T) {
 }
 
 func TestErrorCreateUnionIter(t *testing.T) {
-	t.Parallel()
 	retriever := newMockedRetriever(t).SetAllowedMethod("Iter", "IterReverse").SetData([]*kv.Entry{
 		{Key: kv.Key("k1"), Value: []byte("")},
 	})
@@ -1193,7 +1183,6 @@ func checkCreatedIterClosed(t *testing.T, retriever *mockedRetriever, snap *mock
 }
 
 func TestIterTable(t *testing.T) {
-	t.Parallel()
 	is := newMockedInfoSchema(t).
 		AddTable(model.TempTableNone, 1).
 		AddTable(model.TempTableGlobal, 3).
@@ -1346,7 +1335,6 @@ func TestIterTable(t *testing.T) {
 }
 
 func TestOnIter(t *testing.T) {
-	t.Parallel()
 	is := newMockedInfoSchema(t).
 		AddTable(model.TempTableNone, 1).
 		AddTable(model.TempTableGlobal, 3).
@@ -1556,7 +1544,6 @@ func TestOnIter(t *testing.T) {
 }
 
 func TestOnIterReverse(t *testing.T) {
-	t.Parallel()
 	is := newMockedInfoSchema(t).
 		AddTable(model.TempTableNone, 1).
 		AddTable(model.TempTableGlobal, 3).
diff --git a/tablecodec/tablecodec_test.go b/tablecodec/tablecodec_test.go
index 83839d4463a89..68bc669ce710b 100644
--- a/tablecodec/tablecodec_test.go
+++ b/tablecodec/tablecodec_test.go
@@ -35,7 +35,6 @@ import (
 // TestTableCodec  tests some functions in package tablecodec
 // TODO: add more tests.
 func TestTableCodec(t *testing.T) {
-	t.Parallel()
 	key := EncodeRowKey(1, codec.EncodeInt(nil, 2))
 	h, err := DecodeRowKey(key)
 	require.NoError(t, err)
@@ -68,7 +67,6 @@ type column struct {
 }
 
 func TestRowCodec(t *testing.T) {
-	t.Parallel()
 	c1 := &column{id: 1, tp: types.NewFieldType(mysql.TypeLonglong)}
 	c2 := &column{id: 2, tp: types.NewFieldType(mysql.TypeVarchar)}
 	c3 := &column{id: 3, tp: types.NewFieldType(mysql.TypeNewDecimal)}
@@ -156,7 +154,6 @@ func TestRowCodec(t *testing.T) {
 }
 
 func TestDecodeColumnValue(t *testing.T) {
-	t.Parallel()
 	sc := &stmtctx.StatementContext{TimeZone: time.Local}
 
 	// test timestamp
@@ -221,7 +218,6 @@ func TestDecodeColumnValue(t *testing.T) {
 }
 
 func TestUnflattenDatums(t *testing.T) {
-	t.Parallel()
 	sc := &stmtctx.StatementContext{TimeZone: time.UTC}
 	input := types.MakeDatums(int64(1))
 	tps := []*types.FieldType{types.NewFieldType(mysql.TypeLonglong)}
@@ -243,7 +239,6 @@ func TestUnflattenDatums(t *testing.T) {
 }
 
 func TestTimeCodec(t *testing.T) {
-	t.Parallel()
 	c1 := &column{id: 1, tp: types.NewFieldType(mysql.TypeLonglong)}
 	c2 := &column{id: 2, tp: types.NewFieldType(mysql.TypeVarchar)}
 	c3 := &column{id: 3, tp: types.NewFieldType(mysql.TypeTimestamp)}
@@ -293,7 +288,6 @@ func TestTimeCodec(t *testing.T) {
 }
 
 func TestCutRow(t *testing.T) {
-	t.Parallel()
 	var err error
 	c1 := &column{id: 1, tp: types.NewFieldType(mysql.TypeLonglong)}
 	c2 := &column{id: 2, tp: types.NewFieldType(mysql.TypeVarchar)}
@@ -346,7 +340,6 @@ func TestCutRow(t *testing.T) {
 }
 
 func TestCutKeyNew(t *testing.T) {
-	t.Parallel()
 	values := []types.Datum{types.NewIntDatum(1), types.NewBytesDatum([]byte("abc")), types.NewFloat64Datum(5.5)}
 	handle := types.NewIntDatum(100)
 	values = append(values, handle)
@@ -369,7 +362,6 @@ func TestCutKeyNew(t *testing.T) {
 }
 
 func TestCutKey(t *testing.T) {
-	t.Parallel()
 	colIDs := []int64{1, 2, 3}
 	values := []types.Datum{types.NewIntDatum(1), types.NewBytesDatum([]byte("abc")), types.NewFloat64Datum(5.5)}
 	handle := types.NewIntDatum(100)
@@ -406,7 +398,6 @@ func TestDecodeBadDecical(t *testing.T) {
 }
 
 func TestIndexKey(t *testing.T) {
-	t.Parallel()
 	tableID := int64(4)
 	indexID := int64(5)
 	indexKey := EncodeIndexSeekKey(tableID, indexID, []byte{})
@@ -418,7 +409,6 @@ func TestIndexKey(t *testing.T) {
 }
 
 func TestRecordKey(t *testing.T) {
-	t.Parallel()
 	tableID := int64(55)
 	tableKey := EncodeRowKeyWithHandle(tableID, kv.IntHandle(math.MaxUint32))
 	tTableID, _, isRecordKey, err := DecodeKeyHead(tableKey)
@@ -446,7 +436,6 @@ func TestRecordKey(t *testing.T) {
 }
 
 func TestPrefix(t *testing.T) {
-	t.Parallel()
 	const tableID int64 = 66
 	key := EncodeTablePrefix(tableID)
 	tTableID := DecodeTableID(key)
@@ -472,7 +461,6 @@ func TestPrefix(t *testing.T) {
 }
 
 func TestDecodeIndexKey(t *testing.T) {
-	t.Parallel()
 	tableID := int64(4)
 	indexID := int64(5)
 	values := []types.Datum{
@@ -507,7 +495,6 @@ func TestDecodeIndexKey(t *testing.T) {
 }
 
 func TestCutPrefix(t *testing.T) {
-	t.Parallel()
 	key := EncodeTableIndexPrefix(42, 666)
 	res := CutRowKeyPrefix(key)
 	require.Equal(t, []byte{0x80, 0x0, 0x0, 0x0, 0x0, 0x0, 0x2, 0x9a}, res)
@@ -516,7 +503,6 @@ func TestCutPrefix(t *testing.T) {
 }
 
 func TestRange(t *testing.T) {
-	t.Parallel()
 	s1, e1 := GetTableHandleKeyRange(22)
 	s2, e2 := GetTableHandleKeyRange(23)
 	require.Less(t, string(s1), string(e1))
@@ -531,7 +517,6 @@ func TestRange(t *testing.T) {
 }
 
 func TestDecodeAutoIDMeta(t *testing.T) {
-	t.Parallel()
 	keyBytes := []byte{0x6d, 0x44, 0x42, 0x3a, 0x35, 0x36, 0x0, 0x0, 0x0, 0xfc, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x68, 0x54, 0x49, 0x44, 0x3a, 0x31, 0x30, 0x38, 0x0, 0xfe}
 	key, field, err := DecodeMetaKey(keyBytes)
 	require.NoError(t, err)
@@ -578,7 +563,6 @@ func BenchmarkEncodeValue(b *testing.B) {
 }
 
 func TestError(t *testing.T) {
-	t.Parallel()
 	kvErrs := []*terror.Error{
 		errInvalidKey,
 		errInvalidRecordKey,
@@ -592,7 +576,6 @@ func TestError(t *testing.T) {
 }
 
 func TestUntouchedIndexKValue(t *testing.T) {
-	t.Parallel()
 	untouchedIndexKey := []byte("t00000001_i000000001")
 	untouchedIndexValue := []byte{0, 0, 0, 0, 0, 0, 0, 1, 49}
 	require.True(t, IsUntouchedIndexKValue(untouchedIndexKey, untouchedIndexValue))
diff --git a/telemetry/cte_test/cte_test.go b/telemetry/cte_test/cte_test.go
index 6eaff23ee88e2..356b65eaad059 100644
--- a/telemetry/cte_test/cte_test.go
+++ b/telemetry/cte_test/cte_test.go
@@ -49,8 +49,6 @@ func TestCTEPreviewAndReport(t *testing.T) {
 		t.Skip("integration.NewClusterV3 will create file contains a colon which is not allowed on Windows")
 	}
 
-	t.Parallel()
-
 	s := newSuite(t)
 	defer s.close()
 
diff --git a/telemetry/data_cluster_hardware_test.go b/telemetry/data_cluster_hardware_test.go
index 9980f08dc6b54..90f1c450a8601 100644
--- a/telemetry/data_cluster_hardware_test.go
+++ b/telemetry/data_cluster_hardware_test.go
@@ -21,8 +21,6 @@ import (
 )
 
 func TestNormalizeDiskName(t *testing.T) {
-	t.Parallel()
-
 	tests := []struct {
 		diskName string
 		expected string
@@ -39,8 +37,6 @@ func TestNormalizeDiskName(t *testing.T) {
 }
 
 func TestIsNormalizedDiskNameAllowed(t *testing.T) {
-	t.Parallel()
-
 	tests := []struct {
 		diskName string
 	}{
@@ -66,8 +62,6 @@ func TestIsNormalizedDiskNameAllowed(t *testing.T) {
 }
 
 func TestIsNormalizedDiskNameNotAllowed(t *testing.T) {
-	t.Parallel()
-
 	tests := []struct {
 		diskName string
 	}{
@@ -84,8 +78,6 @@ func TestIsNormalizedDiskNameNotAllowed(t *testing.T) {
 }
 
 func TestNormalizeFieldName(t *testing.T) {
-	t.Parallel()
-
 	tests := []struct {
 		fileName string
 		expected string
diff --git a/telemetry/data_feature_usage_test.go b/telemetry/data_feature_usage_test.go
index 8f5536416811c..efe852153a13a 100644
--- a/telemetry/data_feature_usage_test.go
+++ b/telemetry/data_feature_usage_test.go
@@ -25,8 +25,6 @@ import (
 )
 
 func TestTxnUsageInfo(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -70,8 +68,6 @@ func TestTxnUsageInfo(t *testing.T) {
 }
 
 func TestTemporaryTable(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -89,8 +85,6 @@ func TestTemporaryTable(t *testing.T) {
 }
 
 func TestCachedTable(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
diff --git a/telemetry/telemetry_test.go b/telemetry/telemetry_test.go
index 505ca4a5b0d79..c7f3cef8d92a8 100644
--- a/telemetry/telemetry_test.go
+++ b/telemetry/telemetry_test.go
@@ -33,8 +33,6 @@ func TestTrackingID(t *testing.T) {
 		t.Skip("integration.NewClusterV3 will create file contains a colon which is not allowed on Windows")
 	}
 
-	t.Parallel()
-
 	etcdCluster := integration.NewClusterV3(t, &integration.ClusterConfig{Size: 1})
 	defer etcdCluster.Terminate(t)
 
diff --git a/telemetry/util_test.go b/telemetry/util_test.go
index 92643ec6d174e..704302d5014d7 100644
--- a/telemetry/util_test.go
+++ b/telemetry/util_test.go
@@ -21,8 +21,6 @@ import (
 )
 
 func TestHashString(t *testing.T) {
-	t.Parallel()
-
 	actual, err := hashString("127.0.0.1")
 	require.NoError(t, err)
 	require.Equal(t, "4b84b15bff6ee5796152495a230e45e3d7e947d9", actual)
@@ -50,8 +48,6 @@ func TestParseAddress(t *testing.T) {
 		// copy iterator variable into a new variable, see issue #27779
 		test := test
 		t.Run(test.src, func(t *testing.T) {
-			t.Parallel()
-
 			host, port, err := parseAddressAndHash(test.src)
 			require.NoError(t, err)
 
diff --git a/types/binary_literal_test.go b/types/binary_literal_test.go
index bf7cca07266f4..a76f4c5a8dcb1 100644
--- a/types/binary_literal_test.go
+++ b/types/binary_literal_test.go
@@ -24,7 +24,6 @@ import (
 
 func TestBinaryLiteral(t *testing.T) {
 	t.Run("TestTrimLeadingZeroBytes", func(t *testing.T) {
-		t.Parallel()
 		tbl := []struct {
 			Input    []byte
 			Expected []byte
@@ -46,7 +45,6 @@ func TestBinaryLiteral(t *testing.T) {
 	})
 
 	t.Run("TestParseBitStr", func(t *testing.T) {
-		t.Parallel()
 		tbl := []struct {
 			Input    string
 			Expected []byte
@@ -108,7 +106,6 @@ func TestBinaryLiteral(t *testing.T) {
 	})
 
 	t.Run("TestParseBitStr", func(t *testing.T) {
-		t.Parallel()
 		b, err := ParseBitStr("")
 		require.Nil(t, b)
 		require.Error(t, err)
@@ -116,7 +113,6 @@ func TestBinaryLiteral(t *testing.T) {
 	})
 
 	t.Run("TestParseHexStr", func(t *testing.T) {
-		t.Parallel()
 		tbl := []struct {
 			Input    string
 			Expected []byte
@@ -149,7 +145,6 @@ func TestBinaryLiteral(t *testing.T) {
 	})
 
 	t.Run("TestParseHexStr", func(t *testing.T) {
-		t.Parallel()
 		b, err := ParseBitStr("")
 		require.Nil(t, b)
 		require.Error(t, err)
@@ -157,7 +152,6 @@ func TestBinaryLiteral(t *testing.T) {
 	})
 
 	t.Run("TestString", func(t *testing.T) {
-		t.Parallel()
 		tbl := []struct {
 			Input    BinaryLiteral
 			Expected string
@@ -174,7 +168,6 @@ func TestBinaryLiteral(t *testing.T) {
 	})
 
 	t.Run("TestToBitLiteralString", func(t *testing.T) {
-		t.Parallel()
 		tbl := []struct {
 			Input           BinaryLiteral
 			TrimLeadingZero bool
@@ -200,7 +193,6 @@ func TestBinaryLiteral(t *testing.T) {
 	})
 
 	t.Run("TestToInt", func(t *testing.T) {
-		t.Parallel()
 		tbl := []struct {
 			Input    string
 			Expected uint64
@@ -230,7 +222,6 @@ func TestBinaryLiteral(t *testing.T) {
 	})
 
 	t.Run("TestNewBinaryLiteralFromUint", func(t *testing.T) {
-		t.Parallel()
 		tbl := []struct {
 			Input    uint64
 			ByteSize int
@@ -267,7 +258,6 @@ func TestBinaryLiteral(t *testing.T) {
 	})
 
 	t.Run("TestCompare", func(t *testing.T) {
-		t.Parallel()
 		tbl := []struct {
 			a   BinaryLiteral
 			b   BinaryLiteral
@@ -284,7 +274,6 @@ func TestBinaryLiteral(t *testing.T) {
 	})
 
 	t.Run("TestToString", func(t *testing.T) {
-		t.Parallel()
 		h, _ := NewHexLiteral("x'3A3B'")
 		str := h.ToString()
 		require.Equal(t, str, ":;")
diff --git a/types/compare_test.go b/types/compare_test.go
index ae701553a0e5a..53df667ccca9f 100644
--- a/types/compare_test.go
+++ b/types/compare_test.go
@@ -26,8 +26,6 @@ import (
 )
 
 func TestCompare(t *testing.T) {
-	t.Parallel()
-
 	cmpTbl := []struct {
 		lhs interface{}
 		rhs interface{}
@@ -156,8 +154,6 @@ func compareForTest(a, b interface{}) (int, error) {
 }
 
 func TestCompareDatum(t *testing.T) {
-	t.Parallel()
-
 	cmpTbl := []struct {
 		lhs Datum
 		rhs Datum
@@ -186,8 +182,6 @@ func TestCompareDatum(t *testing.T) {
 }
 
 func TestVecCompareIntAndUint(t *testing.T) {
-	t.Parallel()
-
 	cmpTblUU := []struct {
 		lhs []uint64
 		rhs []uint64
diff --git a/types/const_test.go b/types/const_test.go
index 3bcb9a9bf2caf..62a4d2183eae1 100644
--- a/types/const_test.go
+++ b/types/const_test.go
@@ -25,8 +25,6 @@ import (
 )
 
 func TestGetSQLMode(t *testing.T) {
-	t.Parallel()
-
 	positiveCases := []struct {
 		arg string
 	}{
@@ -59,8 +57,6 @@ func TestGetSQLMode(t *testing.T) {
 }
 
 func TestSQLMode(t *testing.T) {
-	t.Parallel()
-
 	tests := []struct {
 		arg                           string
 		hasNoZeroDateMode             bool
@@ -87,8 +83,6 @@ func TestSQLMode(t *testing.T) {
 }
 
 func TestRealAsFloatMode(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -111,8 +105,6 @@ func TestRealAsFloatMode(t *testing.T) {
 }
 
 func TestPipesAsConcatMode(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -123,8 +115,6 @@ func TestPipesAsConcatMode(t *testing.T) {
 }
 
 func TestIssue22387(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -138,8 +128,6 @@ func TestIssue22387(t *testing.T) {
 }
 
 func TestIssue22389(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -157,8 +145,6 @@ func TestIssue22389(t *testing.T) {
 }
 
 func TestIssue22390(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -177,8 +163,6 @@ func TestIssue22390(t *testing.T) {
 }
 
 func TestIssue22442(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -191,8 +175,6 @@ func TestIssue22442(t *testing.T) {
 }
 
 func TestIssue22444(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -205,8 +187,6 @@ func TestIssue22444(t *testing.T) {
 }
 
 func TestIssue22445(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -220,8 +200,6 @@ func TestIssue22445(t *testing.T) {
 }
 
 func TestIssue22446(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -234,8 +212,6 @@ func TestIssue22446(t *testing.T) {
 }
 
 func TestIssue22447(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -250,8 +226,6 @@ func TestIssue22447(t *testing.T) {
 }
 
 func TestNoUnsignedSubtractionMode(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -338,8 +312,6 @@ func TestNoUnsignedSubtractionMode(t *testing.T) {
 }
 
 func TestHighNotPrecedenceMode(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -360,8 +332,6 @@ func TestHighNotPrecedenceMode(t *testing.T) {
 }
 
 func TestIgnoreSpaceMode(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -426,8 +396,6 @@ func TestIgnoreSpaceMode(t *testing.T) {
 }
 
 func TestNoBackslashEscapesMode(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -441,8 +409,6 @@ func TestNoBackslashEscapesMode(t *testing.T) {
 }
 
 func TestServerStatus(t *testing.T) {
-	t.Parallel()
-
 	tests := []struct {
 		arg            uint16
 		IsCursorExists bool
diff --git a/types/convert_test.go b/types/convert_test.go
index 17312f1c2937b..581eab51cae6e 100644
--- a/types/convert_test.go
+++ b/types/convert_test.go
@@ -46,7 +46,6 @@ func Convert(val interface{}, target *FieldType) (v interface{}, err error) {
 }
 
 func TestConvertType(t *testing.T) {
-	t.Parallel()
 	ft := NewFieldType(mysql.TypeBlob)
 	ft.Flen = 4
 	ft.Charset = "utf8"
@@ -334,7 +333,6 @@ func testToString(t *testing.T, val interface{}, expect string) {
 }
 
 func TestConvertToString(t *testing.T) {
-	t.Parallel()
 	testToString(t, "0", "0")
 	testToString(t, true, "1")
 	testToString(t, "false", "false")
@@ -436,7 +434,6 @@ func testStrToFloat(t *testing.T, str string, expect float64, truncateAsErr bool
 }
 
 func TestStrToNum(t *testing.T) {
-	t.Parallel()
 	testStrToInt(t, "0", 0, true, nil)
 	testStrToInt(t, "-1", -1, true, nil)
 	testStrToInt(t, "100", 100, true, nil)
@@ -515,7 +512,6 @@ func testSelectUpdateDeleteEmptyStringError(t *testing.T) {
 }
 
 func TestFieldTypeToStr(t *testing.T) {
-	t.Parallel()
 	v := TypeToStr(mysql.TypeUnspecified, "not binary")
 	require.Equal(t, TypeStr(mysql.TypeUnspecified), v)
 	v = TypeToStr(mysql.TypeBlob, charset.CharsetBin)
@@ -583,7 +579,6 @@ func strvalue(v interface{}) string {
 }
 
 func TestConvert(t *testing.T) {
-	t.Parallel()
 	// integer ranges
 	signedDeny(t, mysql.TypeTiny, -129, "-128")
 	signedAccept(t, mysql.TypeTiny, -128, "-128")
@@ -775,7 +770,6 @@ func TestConvert(t *testing.T) {
 }
 
 func TestRoundIntStr(t *testing.T) {
-	t.Parallel()
 	cases := []struct {
 		a string
 		b byte
@@ -791,7 +785,6 @@ func TestRoundIntStr(t *testing.T) {
 }
 
 func TestGetValidInt(t *testing.T) {
-	t.Parallel()
 	tests := []struct {
 		origin  string
 		valid   string
@@ -872,7 +865,6 @@ func TestGetValidInt(t *testing.T) {
 }
 
 func TestGetValidFloat(t *testing.T) {
-	t.Parallel()
 	tests := []struct {
 		origin string
 		valid  string
@@ -933,7 +925,6 @@ func TestGetValidFloat(t *testing.T) {
 // time conversion is complicated including Date/Datetime/Time/Timestamp etc,
 // Timestamp may involving timezone.
 func TestConvertTime(t *testing.T) {
-	t.Parallel()
 	timezones := []*time.Location{
 		time.UTC,
 		time.FixedZone("", 3*3600),
@@ -989,7 +980,6 @@ func testConvertTimeTimeZone(t *testing.T, sc *stmtctx.StatementContext) {
 }
 
 func TestConvertJSONToInt(t *testing.T) {
-	t.Parallel()
 	var tests = []struct {
 		in  string
 		out int64
@@ -1022,7 +1012,6 @@ func TestConvertJSONToInt(t *testing.T) {
 }
 
 func TestConvertJSONToFloat(t *testing.T) {
-	t.Parallel()
 	var tests = []struct {
 		in  interface{}
 		out float64
@@ -1056,7 +1045,6 @@ func TestConvertJSONToFloat(t *testing.T) {
 }
 
 func TestConvertJSONToDecimal(t *testing.T) {
-	t.Parallel()
 	var tests = []struct {
 		in  string
 		out *MyDecimal
@@ -1086,7 +1074,6 @@ func TestConvertJSONToDecimal(t *testing.T) {
 }
 
 func TestNumberToDuration(t *testing.T) {
-	t.Parallel()
 	var testCases = []struct {
 		number int64
 		fsp    int
@@ -1138,7 +1125,6 @@ func TestNumberToDuration(t *testing.T) {
 }
 
 func TestStrToDuration(t *testing.T) {
-	t.Parallel()
 	sc := new(stmtctx.StatementContext)
 	var tests = []struct {
 		str        string
@@ -1158,7 +1144,6 @@ func TestStrToDuration(t *testing.T) {
 }
 
 func TestConvertScientificNotation(t *testing.T) {
-	t.Parallel()
 	cases := []struct {
 		input  string
 		output string
@@ -1194,7 +1179,6 @@ func TestConvertScientificNotation(t *testing.T) {
 }
 
 func TestConvertDecimalStrToUint(t *testing.T) {
-	t.Parallel()
 	cases := []struct {
 		input  string
 		result uint64
diff --git a/types/core_time_test.go b/types/core_time_test.go
index 07e4d040a5c2c..18d21ddaf8563 100644
--- a/types/core_time_test.go
+++ b/types/core_time_test.go
@@ -22,8 +22,6 @@ import (
 )
 
 func TestWeekBehaviour(t *testing.T) {
-	t.Parallel()
-
 	require.Equal(t, weekBehaviour(1), weekBehaviourMondayFirst)
 	require.Equal(t, weekBehaviour(2), weekBehaviourYear)
 	require.Equal(t, weekBehaviour(4), weekBehaviourFirstWeekday)
@@ -34,8 +32,6 @@ func TestWeekBehaviour(t *testing.T) {
 }
 
 func TestWeek(t *testing.T) {
-	t.Parallel()
-
 	tests := []struct {
 		Input  CoreTime
 		Mode   int
@@ -53,8 +49,6 @@ func TestWeek(t *testing.T) {
 }
 
 func TestCalcDaynr(t *testing.T) {
-	t.Parallel()
-
 	require.Equal(t, 0, calcDaynr(0, 0, 0))
 	require.Equal(t, 3652424, calcDaynr(9999, 12, 31))
 	require.Equal(t, 719528, calcDaynr(1970, 1, 1))
@@ -64,8 +58,6 @@ func TestCalcDaynr(t *testing.T) {
 }
 
 func TestCalcTimeTimeDiff(t *testing.T) {
-	t.Parallel()
-
 	tests := []struct {
 		T1           CoreTime
 		T2           CoreTime
@@ -105,8 +97,6 @@ func TestCalcTimeTimeDiff(t *testing.T) {
 }
 
 func TestCompareTime(t *testing.T) {
-	t.Parallel()
-
 	tests := []struct {
 		T1     CoreTime
 		T2     CoreTime
@@ -126,8 +116,6 @@ func TestCompareTime(t *testing.T) {
 }
 
 func TestGetDateFromDaynr(t *testing.T) {
-	t.Parallel()
-
 	tests := []struct {
 		daynr uint
 		year  uint
@@ -157,8 +145,6 @@ func TestGetDateFromDaynr(t *testing.T) {
 }
 
 func TestMixDateAndTime(t *testing.T) {
-	t.Parallel()
-
 	tests := []struct {
 		date   CoreTime
 		dur    Duration
@@ -208,8 +194,6 @@ func TestMixDateAndTime(t *testing.T) {
 }
 
 func TestIsLeapYear(t *testing.T) {
-	t.Parallel()
-
 	tests := []struct {
 		T      CoreTime
 		Expect bool
@@ -234,8 +218,6 @@ func TestIsLeapYear(t *testing.T) {
 	}
 }
 func TestGetLastDay(t *testing.T) {
-	t.Parallel()
-
 	tests := []struct {
 		year        int
 		month       int
@@ -255,8 +237,6 @@ func TestGetLastDay(t *testing.T) {
 }
 
 func TestGetFixDays(t *testing.T) {
-	t.Parallel()
-
 	tests := []struct {
 		year        int
 		month       int
@@ -278,8 +258,6 @@ func TestGetFixDays(t *testing.T) {
 }
 
 func TestAddDate(t *testing.T) {
-	t.Parallel()
-
 	tests := []struct {
 		year  int
 		month int
@@ -300,8 +278,6 @@ func TestAddDate(t *testing.T) {
 }
 
 func TestWeekday(t *testing.T) {
-	t.Parallel()
-
 	tests := []struct {
 		Input  CoreTime
 		Expect string
@@ -318,7 +294,6 @@ func TestWeekday(t *testing.T) {
 }
 
 func TestFindZoneTransition(t *testing.T) {
-	t.Parallel()
 	tests := []struct {
 		TZ      string
 		dt      string
@@ -358,7 +333,6 @@ func TestFindZoneTransition(t *testing.T) {
 }
 
 func TestAdjustedGoTime(t *testing.T) {
-	t.Parallel()
 	tests := []struct {
 		TZ      string
 		dt      CoreTime
diff --git a/types/datum_test.go b/types/datum_test.go
index fd433d1e3fb19..038205e89b833 100644
--- a/types/datum_test.go
+++ b/types/datum_test.go
@@ -31,7 +31,6 @@ import (
 )
 
 func TestDatum(t *testing.T) {
-	t.Parallel()
 	values := []interface{}{
 		int64(1),
 		uint64(1),
@@ -62,7 +61,6 @@ func testDatumToBool(t *testing.T, in interface{}, res int) {
 }
 
 func TestToBool(t *testing.T) {
-	t.Parallel()
 	testDatumToBool(t, 0, 0)
 	testDatumToBool(t, int64(0), 0)
 	testDatumToBool(t, uint64(0), 0)
@@ -123,7 +121,6 @@ func testDatumToInt64(t *testing.T, val interface{}, expect int64) {
 }
 
 func TestToInt64(t *testing.T) {
-	t.Parallel()
 	testDatumToInt64(t, "0", int64(0))
 	testDatumToInt64(t, 0, int64(0))
 	testDatumToInt64(t, int64(0), int64(0))
@@ -153,7 +150,6 @@ func TestToInt64(t *testing.T) {
 }
 
 func TestConvertToFloat(t *testing.T) {
-	t.Parallel()
 	testCases := []struct {
 		d      Datum
 		tp     byte
@@ -206,7 +202,6 @@ func mustParseTimeIntoDatum(s string, tp byte, fsp int8) (d Datum) {
 }
 
 func TestToJSON(t *testing.T) {
-	t.Parallel()
 	ft := NewFieldType(mysql.TypeJSON)
 	sc := new(stmtctx.StatementContext)
 	tests := []struct {
@@ -246,7 +241,6 @@ func TestToJSON(t *testing.T) {
 }
 
 func TestIsNull(t *testing.T) {
-	t.Parallel()
 	tests := []struct {
 		data   interface{}
 		isnull bool
@@ -269,7 +263,6 @@ func testIsNull(t *testing.T, data interface{}, isnull bool) {
 }
 
 func TestToBytes(t *testing.T) {
-	t.Parallel()
 	tests := []struct {
 		a   Datum
 		out []byte
@@ -290,7 +283,6 @@ func TestToBytes(t *testing.T) {
 }
 
 func TestComputePlusAndMinus(t *testing.T) {
-	t.Parallel()
 	sc := &stmtctx.StatementContext{TimeZone: time.UTC}
 	tests := []struct {
 		a      Datum
@@ -319,7 +311,6 @@ func TestComputePlusAndMinus(t *testing.T) {
 }
 
 func TestCloneDatum(t *testing.T) {
-	t.Parallel()
 	var raw Datum
 	raw.b = []byte("raw")
 	raw.k = KindRaw
@@ -366,7 +357,6 @@ func newRetTypeWithFlenDecimal(tp byte, flen int, decimal int) *FieldType {
 }
 
 func TestEstimatedMemUsage(t *testing.T) {
-	t.Parallel()
 	b := []byte{'a', 'b', 'c', 'd'}
 	enum := Enum{Name: "a", Value: 1}
 	datumArray := []Datum{
@@ -386,7 +376,6 @@ func TestEstimatedMemUsage(t *testing.T) {
 }
 
 func TestChangeReverseResultByUpperLowerBound(t *testing.T) {
-	t.Parallel()
 	sc := new(stmtctx.StatementContext)
 	sc.IgnoreTruncate = true
 	sc.OverflowAsWarning = true
@@ -501,7 +490,6 @@ func prepareCompareDatums() ([]Datum, []Datum) {
 }
 
 func TestStringToMysqlBit(t *testing.T) {
-	t.Parallel()
 	tests := []struct {
 		a   Datum
 		out []byte
diff --git a/types/errors_test.go b/types/errors_test.go
index c1aefaec27037..00e2dd4e211e4 100644
--- a/types/errors_test.go
+++ b/types/errors_test.go
@@ -22,8 +22,6 @@ import (
 )
 
 func TestError(t *testing.T) {
-	t.Parallel()
-
 	kvErrs := []*terror.Error{
 		ErrInvalidDefault,
 		ErrDataTooLong,
diff --git a/types/etc_test.go b/types/etc_test.go
index 18bdebd30c48e..8a18ffd84e7d3 100644
--- a/types/etc_test.go
+++ b/types/etc_test.go
@@ -36,8 +36,6 @@ func testIsTypeChar(t *testing.T, tp byte, expect bool) {
 }
 
 func TestIsType(t *testing.T) {
-	t.Parallel()
-
 	testIsTypeBlob(t, mysql.TypeTinyBlob, true)
 	testIsTypeBlob(t, mysql.TypeMediumBlob, true)
 	testIsTypeBlob(t, mysql.TypeBlob, true)
@@ -60,8 +58,6 @@ func testTypeToStr(t *testing.T, tp byte, charset string, expect string) {
 }
 
 func TestTypeToStr(t *testing.T) {
-	t.Parallel()
-
 	testTypeStr(t, mysql.TypeYear, "year")
 	testTypeStr(t, 0xdd, "")
 
@@ -98,8 +94,6 @@ func TestTypeToStr(t *testing.T) {
 }
 
 func TestEOFAsNil(t *testing.T) {
-	t.Parallel()
-
 	err := EOFAsNil(io.EOF)
 	require.NoError(t, err)
 	err = EOFAsNil(errors.New("test"))
@@ -107,8 +101,6 @@ func TestEOFAsNil(t *testing.T) {
 }
 
 func TestMaxFloat(t *testing.T) {
-	t.Parallel()
-
 	tests := []struct {
 		flen    int
 		decimal int
@@ -126,8 +118,6 @@ func TestMaxFloat(t *testing.T) {
 }
 
 func TestRoundFloat(t *testing.T) {
-	t.Parallel()
-
 	tests := []struct {
 		input  float64
 		expect float64
@@ -149,8 +139,6 @@ func TestRoundFloat(t *testing.T) {
 }
 
 func TestRound(t *testing.T) {
-	t.Parallel()
-
 	tests := []struct {
 		input  float64
 		dec    int
@@ -170,8 +158,6 @@ func TestRound(t *testing.T) {
 }
 
 func TestTruncateFloat(t *testing.T) {
-	t.Parallel()
-
 	tests := []struct {
 		input   float64
 		flen    int
@@ -194,8 +180,6 @@ func TestTruncateFloat(t *testing.T) {
 }
 
 func TestIsTypeTemporal(t *testing.T) {
-	t.Parallel()
-
 	res := IsTypeTemporal(mysql.TypeDuration)
 	require.True(t, res)
 	res = IsTypeTemporal(mysql.TypeDatetime)
@@ -211,8 +195,6 @@ func TestIsTypeTemporal(t *testing.T) {
 }
 
 func TestIsBinaryStr(t *testing.T) {
-	t.Parallel()
-
 	in := FieldType{
 		Tp:      mysql.TypeBit,
 		Flag:    mysql.UnsignedFlag,
@@ -235,8 +217,6 @@ func TestIsBinaryStr(t *testing.T) {
 }
 
 func TestIsNonBinaryStr(t *testing.T) {
-	t.Parallel()
-
 	in := FieldType{
 		Tp:      mysql.TypeBit,
 		Flag:    mysql.UnsignedFlag,
@@ -260,8 +240,6 @@ func TestIsNonBinaryStr(t *testing.T) {
 }
 
 func TestIsTemporalWithDate(t *testing.T) {
-	t.Parallel()
-
 	res := IsTemporalWithDate(mysql.TypeDatetime)
 	require.True(t, res)
 
@@ -276,8 +254,6 @@ func TestIsTemporalWithDate(t *testing.T) {
 }
 
 func TestIsTypePrefixable(t *testing.T) {
-	t.Parallel()
-
 	res := IsTypePrefixable('t')
 	require.False(t, res)
 
@@ -286,8 +262,6 @@ func TestIsTypePrefixable(t *testing.T) {
 }
 
 func TestIsTypeFractionable(t *testing.T) {
-	t.Parallel()
-
 	res := IsTypeFractionable(mysql.TypeDatetime)
 	require.True(t, res)
 
@@ -302,8 +276,6 @@ func TestIsTypeFractionable(t *testing.T) {
 }
 
 func TestIsTypeNumeric(t *testing.T) {
-	t.Parallel()
-
 	res := IsTypeNumeric(mysql.TypeBit)
 	require.True(t, res)
 
diff --git a/types/field_type_test.go b/types/field_type_test.go
index 73b40fea3b920..cc4dd9db0765b 100644
--- a/types/field_type_test.go
+++ b/types/field_type_test.go
@@ -23,8 +23,6 @@ import (
 )
 
 func TestFieldType(t *testing.T) {
-	t.Parallel()
-
 	ft := NewFieldType(mysql.TypeDuration)
 	require.Equal(t, UnspecifiedLength, ft.Flen)
 	require.Equal(t, UnspecifiedLength, ft.Decimal)
@@ -158,8 +156,6 @@ func TestFieldType(t *testing.T) {
 }
 
 func TestDefaultTypeForValue(t *testing.T) {
-	t.Parallel()
-
 	tests := []struct {
 		value     interface{}
 		tp        byte
@@ -210,8 +206,6 @@ func TestDefaultTypeForValue(t *testing.T) {
 }
 
 func TestAggFieldType(t *testing.T) {
-	t.Parallel()
-
 	fts := []*FieldType{
 		NewFieldType(mysql.TypeUnspecified),
 		NewFieldType(mysql.TypeTiny),
@@ -306,8 +300,6 @@ func TestAggFieldType(t *testing.T) {
 }
 
 func TestAggFieldTypeForTypeFlag(t *testing.T) {
-	t.Parallel()
-
 	types := []*FieldType{
 		NewFieldType(mysql.TypeLonglong),
 		NewFieldType(mysql.TypeLonglong),
@@ -335,8 +327,6 @@ func TestAggFieldTypeForTypeFlag(t *testing.T) {
 }
 
 func TestAggFieldTypeForIntegralPromotion(t *testing.T) {
-	t.Parallel()
-
 	fts := []*FieldType{
 		NewFieldType(mysql.TypeTiny),
 		NewFieldType(mysql.TypeShort),
@@ -375,8 +365,6 @@ func TestAggFieldTypeForIntegralPromotion(t *testing.T) {
 }
 
 func TestAggregateEvalType(t *testing.T) {
-	t.Parallel()
-
 	fts := []*FieldType{
 		NewFieldType(mysql.TypeUnspecified),
 		NewFieldType(mysql.TypeTiny),
diff --git a/types/format_test.go b/types/format_test.go
index c33b9985975d9..95f20cacb727e 100644
--- a/types/format_test.go
+++ b/types/format_test.go
@@ -24,8 +24,6 @@ import (
 )
 
 func TestTimeFormatMethod(t *testing.T) {
-	t.Parallel()
-
 	sc := mock.NewContext().GetSessionVars().StmtCtx
 	sc.IgnoreZeroInDate = true
 	tblDate := []struct {
@@ -81,8 +79,6 @@ func TestTimeFormatMethod(t *testing.T) {
 }
 
 func TestStrToDate(t *testing.T) {
-	t.Parallel()
-
 	sc := mock.NewContext().GetSessionVars().StmtCtx
 	sc.IgnoreZeroInDate = true
 	tests := []struct {
diff --git a/types/fsp_test.go b/types/fsp_test.go
index 7f5761ba7bd42..1daa31ee82c72 100644
--- a/types/fsp_test.go
+++ b/types/fsp_test.go
@@ -22,7 +22,6 @@ import (
 )
 
 func TestCheckFsp(t *testing.T) {
-	t.Parallel()
 	obtained, err := CheckFsp(int(UnspecifiedFsp))
 	require.Equal(t, DefaultFsp, obtained)
 	require.NoError(t, err)
@@ -62,7 +61,6 @@ func TestCheckFsp(t *testing.T) {
 }
 
 func TestParseFrac(t *testing.T) {
-	t.Parallel()
 	obtained, overflow, err := ParseFrac("", 5)
 	require.Equal(t, 0, obtained)
 	require.False(t, overflow)
@@ -121,7 +119,6 @@ func TestParseFrac(t *testing.T) {
 }
 
 func TestAlignFrac(t *testing.T) {
-	t.Parallel()
 	obtained := alignFrac("100", 6)
 	require.Equal(t, "100000", obtained)
 	obtained = alignFrac("10000000000", 6)
diff --git a/types/helper_test.go b/types/helper_test.go
index 13d866aeb0a34..dc3fc9093aad3 100644
--- a/types/helper_test.go
+++ b/types/helper_test.go
@@ -23,8 +23,6 @@ import (
 )
 
 func TestStrToInt(t *testing.T) {
-	t.Parallel()
-
 	tests := []struct {
 		input  string
 		output string
@@ -45,8 +43,6 @@ func TestStrToInt(t *testing.T) {
 }
 
 func TestTruncate(t *testing.T) {
-	t.Parallel()
-
 	tests := []struct {
 		f        float64
 		dec      int
@@ -64,8 +60,6 @@ func TestTruncate(t *testing.T) {
 }
 
 func TestTruncateFloatToString(t *testing.T) {
-	t.Parallel()
-
 	tests := []struct {
 		f        float64
 		dec      int
diff --git a/types/json/binary_functions_test.go b/types/json/binary_functions_test.go
index 375a6100ed3a6..664564365e6ac 100644
--- a/types/json/binary_functions_test.go
+++ b/types/json/binary_functions_test.go
@@ -20,8 +20,6 @@ import (
 )
 
 func TestDecodeEscapedUnicode(t *testing.T) {
-	t.Parallel()
-
 	in := "597d"
 	r, size, err := decodeEscapedUnicode([]byte(in))
 	require.NoError(t, err)
diff --git a/types/json/binary_test.go b/types/json/binary_test.go
index e54ed71398d45..e276d81def524 100644
--- a/types/json/binary_test.go
+++ b/types/json/binary_test.go
@@ -24,8 +24,6 @@ import (
 )
 
 func TestBinaryJSONMarshalUnmarshal(t *testing.T) {
-	t.Parallel()
-
 	expectedList := []string{
 		`{"a": [1, "2", {"aa": "bb"}, 4, null], "b": true, "c": null}`,
 		`{"aaaaaaaaaaa": [1, "2", {"aa": "bb"}, 4.1], "bbbbbbbbbb": true, "ccccccccc": "d"}`,
@@ -40,10 +38,12 @@ func TestBinaryJSONMarshalUnmarshal(t *testing.T) {
 }
 
 func TestBinaryJSONExtract(t *testing.T) {
-	t.Parallel()
-
 	bj1 := mustParseBinaryFromString(t, `{"\"hello\"": "world", "a": [1, "2", {"aa": "bb"}, 4.0, {"aa": "cc"}], "b": true, "c": ["d"]}`)
 	bj2 := mustParseBinaryFromString(t, `[{"a": 1, "b": true}, 3, 3.5, "hello, world", null, true]`)
+	bj3 := mustParseBinaryFromString(t, `{"properties": {"$type": "TiDB"}}`)
+	bj4 := mustParseBinaryFromString(t, `{"properties": {"$type$type": {"$a$a" : "TiDB"}}}`)
+	bj5 := mustParseBinaryFromString(t, `{"properties": {"$type": {"$a" : {"$b" : "TiDB"}}}}`)
+	bj6 := mustParseBinaryFromString(t, `{"properties": {"$type": {"$a$a" : "TiDB"}},"hello": {"$b$b": "world","$c": "amazing"}}`)
 
 	var tests = []struct {
 		bj              BinaryJSON
@@ -63,10 +63,17 @@ func TestBinaryJSONExtract(t *testing.T) {
 		{bj1, []string{`$.a[*]."aa"`}, mustParseBinaryFromString(t, `["bb", "cc"]`), true, nil},
 		{bj1, []string{`$."\"hello\""`}, mustParseBinaryFromString(t, `"world"`), true, nil},
 		{bj1, []string{`$**[1]`}, mustParseBinaryFromString(t, `"2"`), true, nil},
+		{bj3, []string{`$.properties.$type`}, mustParseBinaryFromString(t, `"TiDB"`), true, nil},
+		{bj4, []string{`$.properties.$type$type`}, mustParseBinaryFromString(t, `{"$a$a" : "TiDB"}`), true, nil},
+		{bj4, []string{`$.properties.$type$type.$a$a`}, mustParseBinaryFromString(t, `"TiDB"`), true, nil},
+		{bj5, []string{`$.properties.$type.$a.$b`}, mustParseBinaryFromString(t, `"TiDB"`), true, nil},
+		{bj5, []string{`$.properties.$type.$a.*[0]`}, mustParseBinaryFromString(t, `"TiDB"`), true, nil},
 
 		// test extract with multi path expressions.
 		{bj1, []string{"$.a", "$[5]"}, mustParseBinaryFromString(t, `[[1, "2", {"aa": "bb"}, 4.0, {"aa": "cc"}]]`), true, nil},
 		{bj2, []string{"$.a", "$[0]"}, mustParseBinaryFromString(t, `[{"a": 1, "b": true}]`), true, nil},
+		{bj6, []string{"$.properties", "$[1]"}, mustParseBinaryFromString(t, `[{"$type": {"$a$a" : "TiDB"}}]`), true, nil},
+		{bj6, []string{"$.hello", "$[2]"}, mustParseBinaryFromString(t, `[{"$b$b": "world","$c": "amazing"}]`), true, nil},
 	}
 
 	for _, test := range tests {
@@ -86,8 +93,6 @@ func TestBinaryJSONExtract(t *testing.T) {
 }
 
 func TestBinaryJSONType(t *testing.T) {
-	t.Parallel()
-
 	var tests = []struct {
 		in  string
 		out string
@@ -111,8 +116,6 @@ func TestBinaryJSONType(t *testing.T) {
 }
 
 func TestBinaryJSONUnquote(t *testing.T) {
-	t.Parallel()
-
 	var tests = []struct {
 		json     string
 		unquoted string
@@ -139,8 +142,6 @@ func TestBinaryJSONUnquote(t *testing.T) {
 }
 
 func TestQuoteString(t *testing.T) {
-	t.Parallel()
-
 	var tests = []struct {
 		raw    string
 		quoted string
@@ -163,8 +164,6 @@ func TestQuoteString(t *testing.T) {
 }
 
 func TestBinaryJSONModify(t *testing.T) {
-	t.Parallel()
-
 	var tests = []struct {
 		base     string
 		setField string
@@ -219,8 +218,6 @@ func TestBinaryJSONModify(t *testing.T) {
 }
 
 func TestBinaryJSONRemove(t *testing.T) {
-	t.Parallel()
-
 	var tests = []struct {
 		base     string
 		path     string
@@ -257,8 +254,6 @@ func TestBinaryJSONRemove(t *testing.T) {
 }
 
 func TestCompareBinary(t *testing.T) {
-	t.Parallel()
-
 	jNull := mustParseBinaryFromString(t, `null`)
 	jBoolTrue := mustParseBinaryFromString(t, `true`)
 	jBoolFalse := mustParseBinaryFromString(t, `false`)
@@ -323,8 +318,6 @@ func TestCompareBinary(t *testing.T) {
 }
 
 func TestBinaryJSONMerge(t *testing.T) {
-	t.Parallel()
-
 	var tests = []struct {
 		suffixes []string
 		expected string
@@ -368,8 +361,6 @@ func BenchmarkBinaryMarshal(b *testing.B) {
 }
 
 func TestBinaryJSONContains(t *testing.T) {
-	t.Parallel()
-
 	var tests = []struct {
 		input    string
 		target   string
@@ -401,8 +392,6 @@ func TestBinaryJSONContains(t *testing.T) {
 }
 
 func TestBinaryJSONCopy(t *testing.T) {
-	t.Parallel()
-
 	expectedList := []string{
 		`{"a": [1, "2", {"aa": "bb"}, 4, null], "b": true, "c": null}`,
 		`{"aaaaaaaaaaa": [1, "2", {"aa": "bb"}, 4.1], "bbbbbbbbbb": true, "ccccccccc": "d"}`,
@@ -415,8 +404,6 @@ func TestBinaryJSONCopy(t *testing.T) {
 }
 
 func TestGetKeys(t *testing.T) {
-	t.Parallel()
-
 	parsedBJ := mustParseBinaryFromString(t, "[]")
 	require.Equal(t, "[]", parsedBJ.GetKeys().String())
 	parsedBJ = mustParseBinaryFromString(t, "{}")
@@ -434,8 +421,6 @@ func TestGetKeys(t *testing.T) {
 }
 
 func TestBinaryJSONDepth(t *testing.T) {
-	t.Parallel()
-
 	var tests = []struct {
 		input    string
 		expected int
@@ -456,8 +441,6 @@ func TestBinaryJSONDepth(t *testing.T) {
 }
 
 func TestParseBinaryFromString(t *testing.T) {
-	t.Parallel()
-
 	obj, err := ParseBinaryFromString("")
 	require.Error(t, err)
 	require.Equal(t, "", obj.String())
@@ -470,8 +453,6 @@ func TestParseBinaryFromString(t *testing.T) {
 }
 
 func TestCreateBinary(t *testing.T) {
-	t.Parallel()
-
 	bj := CreateBinary(int64(1 << 62))
 	require.Equal(t, TypeCodeInt64, bj.TypeCode)
 	require.NotNil(t, bj.Value)
@@ -502,8 +483,6 @@ func TestCreateBinary(t *testing.T) {
 }
 
 func TestFunctions(t *testing.T) {
-	t.Parallel()
-
 	testByte := []byte{'\\', 'b', 'f', 'n', 'r', 't', 'u', 'z', '0'}
 	testOutput, err := unquoteString(string(testByte))
 	require.Equal(t, "\bfnrtuz0", testOutput)
@@ -519,8 +498,6 @@ func TestFunctions(t *testing.T) {
 }
 
 func TestBinaryJSONExtractCallback(t *testing.T) {
-	t.Parallel()
-
 	bj1 := mustParseBinaryFromString(t, `{"\"hello\"": "world", "a": [1, "2", {"aa": "bb"}, 4.0, {"aa": "cc"}], "b": true, "c": ["d"]}`)
 	bj2 := mustParseBinaryFromString(t, `[{"a": 1, "b": true}, 3, 3.5, "hello, world", null, true]`)
 
@@ -590,8 +567,6 @@ func TestBinaryJSONExtractCallback(t *testing.T) {
 }
 
 func TestBinaryJSONWalk(t *testing.T) {
-	t.Parallel()
-
 	bj1 := mustParseBinaryFromString(t, `["abc", [{"k": "10"}, "def"], {"x":"abc"}, {"y":"bcd"}]`)
 	bj2 := mustParseBinaryFromString(t, `{}`)
 
diff --git a/types/json/path_expr.go b/types/json/path_expr.go
index 9500d759daa9b..5d23c1a16ed3a 100644
--- a/types/json/path_expr.go
+++ b/types/json/path_expr.go
@@ -46,9 +46,9 @@ import (
 		select json_extract('{"a": "b", "c": [1, "2"]}', '$.*') -> ["b", [1, "2"]]
 */
 
-// [a-zA-Z_][a-zA-Z0-9_]* matches any identifier;
+// ([\$]*[a-zA-Z_][a-zA-Z0-9_]*)+ matches any identifier, may start with $ and appear multiple times;
 // "[^"\\]*(\\.[^"\\]*)*" matches any string literal which can carry escaped quotes;
-var jsonPathExprLegRe = regexp.MustCompile(`(\.\s*([a-zA-Z_][a-zA-Z0-9_]*|\*|"[^"\\]*(\\.[^"\\]*)*")|(\[\s*([0-9]+|\*)\s*\])|\*\*)`)
+var jsonPathExprLegRe = regexp.MustCompile(`(\.\s*(([\$]*[a-zA-Z_][a-zA-Z0-9_]*)+|\*|"[^"\\]*(\\.[^"\\]*)*")|(\[\s*([0-9]+|\*)\s*\])|\*\*)`)
 
 type pathLegType byte
 
diff --git a/types/json/path_expr_test.go b/types/json/path_expr_test.go
index 703a34596e482..0d229848da01f 100644
--- a/types/json/path_expr_test.go
+++ b/types/json/path_expr_test.go
@@ -35,7 +35,6 @@ func TestContainsAnyAsterisk(t *testing.T) {
 		// copy iterator variable into a new variable, see issue #27779
 		test := test
 		t.Run(test.expression, func(t *testing.T) {
-			t.Parallel()
 			pe, err := ParseJSONPathExpr(test.expression)
 			require.NoError(t, err)
 			require.Equal(t, test.containsAsterisks, pe.flags.containsAnyAsterisk())
@@ -65,7 +64,6 @@ func TestValidatePathExpr(t *testing.T) {
 		// copy iterator variable into a new variable, see issue #27779
 		test := test
 		t.Run(test.expression, func(t *testing.T) {
-			t.Parallel()
 			pe, err := ParseJSONPathExpr(test.expression)
 			if test.success {
 				require.NoError(t, err)
@@ -91,7 +89,6 @@ func TestPathExprToString(t *testing.T) {
 		// copy iterator variable into a new variable, see issue #27779
 		test := test
 		t.Run(test.expression, func(t *testing.T) {
-			t.Parallel()
 			pe, err := ParseJSONPathExpr(test.expression)
 			require.NoError(t, err)
 			require.Equal(t, test.expression, pe.String())
@@ -118,7 +115,6 @@ func TestPushBackOneIndexLeg(t *testing.T) {
 		// copy iterator variable into a new variable, see issue #27779
 		test := test
 		t.Run(test.expression, func(t *testing.T) {
-			t.Parallel()
 			pe, err := ParseJSONPathExpr(test.expression)
 			require.NoError(t, err)
 
diff --git a/types/mydecimal_test.go b/types/mydecimal_test.go
index 786586493a502..61e86ffb1dc7a 100644
--- a/types/mydecimal_test.go
+++ b/types/mydecimal_test.go
@@ -23,7 +23,6 @@ import (
 )
 
 func TestFromInt(t *testing.T) {
-	t.Parallel()
 	tests := []struct {
 		input  int64
 		output string
@@ -42,7 +41,6 @@ func TestFromInt(t *testing.T) {
 }
 
 func TestFromUint(t *testing.T) {
-	t.Parallel()
 	tests := []struct {
 		input  uint64
 		output string
@@ -60,7 +58,6 @@ func TestFromUint(t *testing.T) {
 }
 
 func TestToInt(t *testing.T) {
-	t.Parallel()
 	tests := []struct {
 		input  string
 		output int64
@@ -86,7 +83,6 @@ func TestToInt(t *testing.T) {
 }
 
 func TestToUint(t *testing.T) {
-	t.Parallel()
 	tests := []struct {
 		input  string
 		output uint64
@@ -112,7 +108,6 @@ func TestToUint(t *testing.T) {
 }
 
 func TestFromFloat(t *testing.T) {
-	t.Parallel()
 	tests := []struct {
 		s string
 		f float64
@@ -131,7 +126,6 @@ func TestFromFloat(t *testing.T) {
 }
 
 func TestToFloat(t *testing.T) {
-	t.Parallel()
 	tests := []struct {
 		in  string
 		out string
@@ -189,7 +183,6 @@ func TestToFloat(t *testing.T) {
 }
 
 func TestToHashKey(t *testing.T) {
-	t.Parallel()
 	tests := []struct {
 		numbers []string
 	}{
@@ -267,7 +260,6 @@ func TestToHashKey(t *testing.T) {
 }
 
 func TestRemoveTrailingZeros(t *testing.T) {
-	t.Parallel()
 	tests := []string{
 		"0", "0.0", ".0", ".00000000", "0.0000", "0000", "0000.0", "0000.000",
 		"-0", "-0.0", "-.0", "-.00000000", "-0.0000", "-0000", "-0000.0", "-0000.000",
@@ -301,7 +293,6 @@ func TestRemoveTrailingZeros(t *testing.T) {
 }
 
 func TestRoundWithHalfEven(t *testing.T) {
-	t.Parallel()
 	tests := []struct {
 		input  string
 		scale  int
@@ -338,7 +329,6 @@ func TestRoundWithHalfEven(t *testing.T) {
 }
 
 func TestRoundWithTruncate(t *testing.T) {
-	t.Parallel()
 	tests := []struct {
 		input  string
 		scale  int
@@ -374,7 +364,6 @@ func TestRoundWithTruncate(t *testing.T) {
 }
 
 func TestRoundWithCeil(t *testing.T) {
-	t.Parallel()
 	tests := []struct {
 		input  string
 		scale  int
@@ -411,7 +400,6 @@ func TestRoundWithCeil(t *testing.T) {
 }
 
 func TestToString(t *testing.T) {
-	t.Parallel()
 	type tcase struct {
 		input  string
 		output string
@@ -431,7 +419,6 @@ func TestToString(t *testing.T) {
 }
 
 func TestToBinFromBin(t *testing.T) {
-	t.Parallel()
 	type tcase struct {
 		input     string
 		precision int
@@ -502,7 +489,6 @@ func TestToBinFromBin(t *testing.T) {
 }
 
 func TestCompareMyDecimal(t *testing.T) {
-	t.Parallel()
 	type tcase struct {
 		a   string
 		b   string
@@ -532,7 +518,6 @@ func TestCompareMyDecimal(t *testing.T) {
 }
 
 func TestMaxDecimal(t *testing.T) {
-	t.Parallel()
 	type tcase struct {
 		prec   int
 		frac   int
@@ -564,7 +549,6 @@ func TestMaxDecimal(t *testing.T) {
 }
 
 func TestNegMyDecimal(t *testing.T) {
-	t.Parallel()
 	type testCase struct {
 		a      string
 		result string
@@ -583,7 +567,6 @@ func TestNegMyDecimal(t *testing.T) {
 }
 
 func TestAddMyDecimal(t *testing.T) {
-	t.Parallel()
 	type testCase struct {
 		a      string
 		b      string
@@ -620,7 +603,6 @@ func TestAddMyDecimal(t *testing.T) {
 }
 
 func TestSubMyDecimal(t *testing.T) {
-	t.Parallel()
 	type tcase struct {
 		a      string
 		b      string
@@ -658,7 +640,6 @@ func TestSubMyDecimal(t *testing.T) {
 }
 
 func TestMulMyDecimal(t *testing.T) {
-	t.Parallel()
 	type tcase struct {
 		a      string
 		b      string
@@ -693,7 +674,6 @@ func TestMulMyDecimal(t *testing.T) {
 }
 
 func TestDivModMyDecimal(t *testing.T) {
-	t.Parallel()
 	type tcase struct {
 		a      string
 		b      string
@@ -801,7 +781,6 @@ func TestDivModMyDecimal(t *testing.T) {
 }
 
 func TestMaxOrMinMyDecimal(t *testing.T) {
-	t.Parallel()
 	type tcase struct {
 		neg    bool
 		prec   int
@@ -822,7 +801,6 @@ func TestMaxOrMinMyDecimal(t *testing.T) {
 }
 
 func TestReset(t *testing.T) {
-	t.Parallel()
 	var x1, y1, z1 MyDecimal
 	require.NoError(t, x1.FromString([]byte("38520.130741106671")))
 	require.NoError(t, y1.FromString([]byte("9863.944799797851")))
diff --git a/types/overflow_test.go b/types/overflow_test.go
index f203d145d46fa..d492b24c75748 100644
--- a/types/overflow_test.go
+++ b/types/overflow_test.go
@@ -23,8 +23,6 @@ import (
 )
 
 func TestAdd(t *testing.T) {
-	t.Parallel()
-
 	tblUint64 := []struct {
 		lsh      uint64
 		rsh      uint64
@@ -100,8 +98,6 @@ func TestAdd(t *testing.T) {
 }
 
 func TestSub(t *testing.T) {
-	t.Parallel()
-
 	tblUint64 := []struct {
 		lsh      uint64
 		rsh      uint64
@@ -200,8 +196,6 @@ func TestSub(t *testing.T) {
 }
 
 func TestMul(t *testing.T) {
-	t.Parallel()
-
 	tblUint64 := []struct {
 		lsh      uint64
 		rsh      uint64
@@ -275,8 +269,6 @@ func TestMul(t *testing.T) {
 }
 
 func TestDiv(t *testing.T) {
-	t.Parallel()
-
 	tblInt64 := []struct {
 		lsh      int64
 		rsh      int64
diff --git a/types/parser_driver/value_expr_test.go b/types/parser_driver/value_expr_test.go
index c0200b27b4467..57225e44755e3 100644
--- a/types/parser_driver/value_expr_test.go
+++ b/types/parser_driver/value_expr_test.go
@@ -47,7 +47,6 @@ func TestValueExprRestore(t *testing.T) {
 		// copy iterator variable into a new variable, see issue #27779
 		test := test
 		t.Run(test.expect, func(t *testing.T) {
-			t.Parallel()
 			var sb strings.Builder
 			expr := &ValueExpr{Datum: test.datum}
 			err := expr.Restore(format.NewRestoreCtx(format.DefaultRestoreFlags, &sb))
diff --git a/types/time.go b/types/time.go
index 8d2a11fc58d90..0ea01c8a85f96 100644
--- a/types/time.go
+++ b/types/time.go
@@ -49,9 +49,9 @@ const (
 	// MaxDuration is the maximum for duration.
 	MaxDuration int64 = 838*10000 + 59*100 + 59
 	// MinTime is the minimum for mysql time type.
-	MinTime = -gotime.Duration(838*3600+59*60+59) * gotime.Second
+	MinTime = -(838*gotime.Hour + 59*gotime.Minute + 59*gotime.Second)
 	// MaxTime is the maximum for mysql time type.
-	MaxTime = gotime.Duration(838*3600+59*60+59) * gotime.Second
+	MaxTime = 838*gotime.Hour + 59*gotime.Minute + 59*gotime.Second
 	// ZeroDatetimeStr is the string representation of a zero datetime.
 	ZeroDatetimeStr = "0000-00-00 00:00:00"
 	// ZeroDateStr is the string representation of a zero date.
@@ -466,7 +466,7 @@ func (t Time) ConvertToDuration() (Duration, error) {
 	hour, minute, second := t.Clock()
 	frac := t.Microsecond() * 1000
 
-	d := gotime.Duration(hour*3600+minute*60+second)*gotime.Second + gotime.Duration(frac)
+	d := gotime.Duration(hour*3600+minute*60+second)*gotime.Second + gotime.Duration(frac) //nolint:durationcheck
 	// TODO: check convert validation
 	return Duration{Duration: d, Fsp: t.Fsp()}, nil
 }
@@ -579,7 +579,7 @@ func RoundFrac(t gotime.Time, fsp int8) (gotime.Time, error) {
 	if err != nil {
 		return t, errors.Trace(err)
 	}
-	return t.Round(gotime.Duration(math.Pow10(9-int(fsp))) * gotime.Nanosecond), nil
+	return t.Round(gotime.Duration(math.Pow10(9-int(fsp))) * gotime.Nanosecond), nil //nolint:durationcheck
 }
 
 // TruncateFrac truncates fractional seconds precision with new fsp and returns a new one.
@@ -589,7 +589,7 @@ func TruncateFrac(t gotime.Time, fsp int8) (gotime.Time, error) {
 	if _, err := CheckFsp(int(fsp)); err != nil {
 		return t, err
 	}
-	return t.Truncate(gotime.Duration(math.Pow10(9-int(fsp))) * gotime.Nanosecond), nil
+	return t.Truncate(gotime.Duration(math.Pow10(9-int(fsp))) * gotime.Nanosecond), nil //nolint:durationcheck
 }
 
 // ToPackedUint encodes Time to a packed uint64 value.
@@ -1270,7 +1270,7 @@ func AdjustYear(y int64, adjustZero bool) (int64, error) {
 // NewDuration construct duration with time.
 func NewDuration(hour, minute, second, microsecond int, fsp int8) Duration {
 	return Duration{
-		Duration: gotime.Duration(hour)*gotime.Hour + gotime.Duration(minute)*gotime.Minute + gotime.Duration(second)*gotime.Second + gotime.Duration(microsecond)*gotime.Microsecond,
+		Duration: gotime.Duration(hour)*gotime.Hour + gotime.Duration(minute)*gotime.Minute + gotime.Duration(second)*gotime.Second + gotime.Duration(microsecond)*gotime.Microsecond, //nolint:durationcheck
 		Fsp:      fsp,
 	}
 }
@@ -1490,7 +1490,7 @@ func (d Duration) RoundFrac(fsp int8, loc *gotime.Location) (Duration, error) {
 	}
 
 	n := gotime.Date(0, 0, 0, 0, 0, 0, 0, tz)
-	nd := n.Add(d.Duration).Round(gotime.Duration(math.Pow10(9-int(fsp))) * gotime.Nanosecond).Sub(n)
+	nd := n.Add(d.Duration).Round(gotime.Duration(math.Pow10(9-int(fsp))) * gotime.Nanosecond).Sub(n) //nolint:durationcheck
 	return Duration{Duration: nd, Fsp: fsp}, nil
 }
 
@@ -1711,7 +1711,7 @@ func matchDuration(str string, fsp int8) (Duration, error) {
 		return Duration{t, fsp}, ErrTruncatedWrongVal.GenWithStackByArgs("time", str)
 	}
 
-	d := gotime.Duration(hhmmss[0]*3600+hhmmss[1]*60+hhmmss[2])*gotime.Second + gotime.Duration(frac)*gotime.Microsecond
+	d := gotime.Duration(hhmmss[0]*3600+hhmmss[1]*60+hhmmss[2])*gotime.Second + gotime.Duration(frac)*gotime.Microsecond //nolint:durationcheck
 	if negative {
 		d = -d
 	}
@@ -1800,11 +1800,11 @@ func splitDuration(t gotime.Duration) (int, int, int, int, int) {
 	}
 
 	hours := t / gotime.Hour
-	t -= hours * gotime.Hour
+	t -= hours * gotime.Hour //nolint:durationcheck
 	minutes := t / gotime.Minute
-	t -= minutes * gotime.Minute
+	t -= minutes * gotime.Minute //nolint:durationcheck
 	seconds := t / gotime.Second
-	t -= seconds * gotime.Second
+	t -= seconds * gotime.Second //nolint:durationcheck
 	fraction := t / gotime.Microsecond
 
 	return sign, int(hours), int(minutes), int(seconds), int(fraction)
diff --git a/types/time_test.go b/types/time_test.go
index fc914034acc73..ca725119d9dd2 100644
--- a/types/time_test.go
+++ b/types/time_test.go
@@ -31,7 +31,6 @@ import (
 )
 
 func TestTimeEncoding(t *testing.T) {
-	t.Parallel()
 	tests := []struct {
 		Year, Month, Day, Hour, Minute, Second, Microsecond int
 		Type                                                uint8
@@ -61,7 +60,6 @@ func TestTimeEncoding(t *testing.T) {
 }
 
 func TestDateTime(t *testing.T) {
-	t.Parallel()
 	sc := mock.NewContext().GetSessionVars().StmtCtx
 	sc.IgnoreZeroInDate = true
 	table := []struct {
@@ -182,7 +180,6 @@ func TestDateTime(t *testing.T) {
 }
 
 func TestTimestamp(t *testing.T) {
-	t.Parallel()
 	table := []struct {
 		Input  string
 		Expect string
@@ -208,7 +205,6 @@ func TestTimestamp(t *testing.T) {
 }
 
 func TestDate(t *testing.T) {
-	t.Parallel()
 	sc := mock.NewContext().GetSessionVars().StmtCtx
 	sc.IgnoreZeroInDate = true
 	table := []struct {
@@ -304,7 +300,6 @@ func TestDate(t *testing.T) {
 }
 
 func TestTime(t *testing.T) {
-	t.Parallel()
 	sc := mock.NewContext().GetSessionVars().StmtCtx
 	sc.IgnoreZeroInDate = true
 	table := []struct {
@@ -399,7 +394,6 @@ func TestTime(t *testing.T) {
 }
 
 func TestDurationAdd(t *testing.T) {
-	t.Parallel()
 	table := []struct {
 		Input    string
 		Fsp      int8
@@ -436,7 +430,6 @@ func TestDurationAdd(t *testing.T) {
 }
 
 func TestDurationSub(t *testing.T) {
-	t.Parallel()
 	sc := mock.NewContext().GetSessionVars().StmtCtx
 	sc.IgnoreZeroInDate = true
 	table := []struct {
@@ -461,7 +454,6 @@ func TestDurationSub(t *testing.T) {
 }
 
 func TestTimeFsp(t *testing.T) {
-	t.Parallel()
 	sc := mock.NewContext().GetSessionVars().StmtCtx
 	sc.IgnoreZeroInDate = true
 	table := []struct {
@@ -501,7 +493,6 @@ func TestTimeFsp(t *testing.T) {
 }
 
 func TestYear(t *testing.T) {
-	t.Parallel()
 	table := []struct {
 		Input  string
 		Expect int16
@@ -563,7 +554,6 @@ func TestYear(t *testing.T) {
 }
 
 func TestCodec(t *testing.T) {
-	t.Parallel()
 	sc := &stmtctx.StatementContext{TimeZone: time.UTC}
 
 	// MySQL timestamp value doesn't allow month=0 or day=0.
@@ -621,7 +611,6 @@ func TestCodec(t *testing.T) {
 }
 
 func TestParseTimeFromNum(t *testing.T) {
-	t.Parallel()
 	table := []struct {
 		Input                int64
 		ExpectDateTimeError  bool
@@ -695,7 +684,6 @@ func TestParseTimeFromNum(t *testing.T) {
 }
 
 func TestToNumber(t *testing.T) {
-	t.Parallel()
 	sc := mock.NewContext().GetSessionVars().StmtCtx
 	sc.IgnoreZeroInDate = true
 	losAngelesTz, err := time.LoadLocation("America/Los_Angeles")
@@ -772,7 +760,6 @@ func TestToNumber(t *testing.T) {
 }
 
 func TestParseTimeFromFloatString(t *testing.T) {
-	t.Parallel()
 	sc := mock.NewContext().GetSessionVars().StmtCtx
 	sc.IgnoreZeroInDate = true
 	table := []struct {
@@ -805,7 +792,6 @@ func TestParseTimeFromFloatString(t *testing.T) {
 }
 
 func TestParseFrac(t *testing.T) {
-	t.Parallel()
 	tbl := []struct {
 		S        string
 		Fsp      int8
@@ -842,7 +828,6 @@ func TestParseFrac(t *testing.T) {
 }
 
 func TestRoundFrac(t *testing.T) {
-	t.Parallel()
 	sc := mock.NewContext().GetSessionVars().StmtCtx
 	sc.IgnoreZeroInDate = true
 	sc.TimeZone = time.UTC
@@ -935,7 +920,6 @@ func TestRoundFrac(t *testing.T) {
 }
 
 func TestConvert(t *testing.T) {
-	t.Parallel()
 	sc := mock.NewContext().GetSessionVars().StmtCtx
 	sc.IgnoreZeroInDate = true
 	losAngelesTz, _ := time.LoadLocation("America/Los_Angeles")
@@ -986,7 +970,6 @@ func TestConvert(t *testing.T) {
 }
 
 func TestCompare(t *testing.T) {
-	t.Parallel()
 	sc := &stmtctx.StatementContext{TimeZone: time.UTC}
 	tbl := []struct {
 		Arg1 string
@@ -1036,7 +1019,6 @@ func TestCompare(t *testing.T) {
 }
 
 func TestDurationClock(t *testing.T) {
-	t.Parallel()
 	// test hour, minute, second and micro second
 	tbl := []struct {
 		Input       string
@@ -1061,7 +1043,6 @@ func TestDurationClock(t *testing.T) {
 }
 
 func TestParseDateFormat(t *testing.T) {
-	t.Parallel()
 	tbl := []struct {
 		Input  string
 		Result []string
@@ -1085,7 +1066,6 @@ func TestParseDateFormat(t *testing.T) {
 }
 
 func TestTimestampDiff(t *testing.T) {
-	t.Parallel()
 	tests := []struct {
 		unit   string
 		t1     types.CoreTime
@@ -1109,7 +1089,6 @@ func TestTimestampDiff(t *testing.T) {
 }
 
 func TestDateFSP(t *testing.T) {
-	t.Parallel()
 	tests := []struct {
 		date   string
 		expect int
@@ -1126,7 +1105,6 @@ func TestDateFSP(t *testing.T) {
 }
 
 func TestConvertTimeZone(t *testing.T) {
-	t.Parallel()
 	loc, _ := time.LoadLocation("Asia/Shanghai")
 	tests := []struct {
 		input  types.CoreTime
@@ -1148,7 +1126,6 @@ func TestConvertTimeZone(t *testing.T) {
 }
 
 func TestTimeAdd(t *testing.T) {
-	t.Parallel()
 	tbl := []struct {
 		Arg1 string
 		Arg2 string
@@ -1179,7 +1156,6 @@ func TestTimeAdd(t *testing.T) {
 }
 
 func TestTruncateOverflowMySQLTime(t *testing.T) {
-	t.Parallel()
 	v := types.MaxTime + 1
 	res, err := types.TruncateOverflowMySQLTime(v)
 	require.True(t, types.ErrTruncatedWrongVal.Equal(err))
@@ -1212,8 +1188,6 @@ func TestTruncateOverflowMySQLTime(t *testing.T) {
 }
 
 func TestCheckTimestamp(t *testing.T) {
-	t.Parallel()
-
 	shanghaiTz, _ := time.LoadLocation("Asia/Shanghai")
 
 	tests := []struct {
@@ -1323,7 +1297,6 @@ func TestCheckTimestamp(t *testing.T) {
 }
 
 func TestExtractDurationValue(t *testing.T) {
-	t.Parallel()
 	tests := []struct {
 		unit   string
 		format string
@@ -1464,14 +1437,12 @@ func TestExtractDurationValue(t *testing.T) {
 }
 
 func TestCurrentTime(t *testing.T) {
-	t.Parallel()
 	res := types.CurrentTime(mysql.TypeTimestamp)
 	require.Equal(t, mysql.TypeTimestamp, res.Type())
 	require.Equal(t, int8(0), res.Fsp())
 }
 
 func TestInvalidZero(t *testing.T) {
-	t.Parallel()
 	in := types.NewTime(types.ZeroCoreTime, mysql.TypeTimestamp, types.DefaultFsp)
 	require.True(t, in.InvalidZero())
 	in.SetCoreTime(types.FromDate(2019, 00, 00, 00, 00, 00, 00))
@@ -1481,7 +1452,6 @@ func TestInvalidZero(t *testing.T) {
 }
 
 func TestGetFsp(t *testing.T) {
-	t.Parallel()
 	res := types.GetFsp("2019:04:12 14:00:00.123456")
 	require.Equal(t, int8(6), res)
 
@@ -1496,7 +1466,6 @@ func TestGetFsp(t *testing.T) {
 }
 
 func TestExtractDatetimeNum(t *testing.T) {
-	t.Parallel()
 	in := types.NewTime(types.FromDate(2019, 04, 12, 14, 00, 00, 0000), mysql.TypeTimestamp, types.DefaultFsp)
 
 	res, err := types.ExtractDatetimeNum(&in, "day")
@@ -1568,7 +1537,6 @@ func TestExtractDatetimeNum(t *testing.T) {
 }
 
 func TestExtractDurationNum(t *testing.T) {
-	t.Parallel()
 	type resultTbl struct {
 		unit   string
 		expect int64
@@ -1634,7 +1602,6 @@ func TestExtractDurationNum(t *testing.T) {
 }
 
 func TestParseDurationValue(t *testing.T) {
-	t.Parallel()
 	tbl := []struct {
 		format string
 		unit   string
@@ -1691,7 +1658,6 @@ func TestParseDurationValue(t *testing.T) {
 }
 
 func TestIsClockUnit(t *testing.T) {
-	t.Parallel()
 	tbl := []struct {
 		input    string
 		expected bool
@@ -1719,7 +1685,6 @@ func TestIsClockUnit(t *testing.T) {
 }
 
 func TestIsDateFormat(t *testing.T) {
-	t.Parallel()
 	input := "1234:321"
 	output := types.IsDateFormat(input)
 	require.False(t, output)
@@ -1734,7 +1699,6 @@ func TestIsDateFormat(t *testing.T) {
 }
 
 func TestParseTimeFromInt64(t *testing.T) {
-	t.Parallel()
 	sc := mock.NewContext().GetSessionVars().StmtCtx
 	sc.IgnoreZeroInDate = true
 
@@ -1753,7 +1717,6 @@ func TestParseTimeFromInt64(t *testing.T) {
 }
 
 func TestGetFormatType(t *testing.T) {
-	t.Parallel()
 	input := "TEST"
 	isDuration, isDate := types.GetFormatType(input)
 	require.False(t, isDuration)
@@ -1771,7 +1734,6 @@ func TestGetFormatType(t *testing.T) {
 }
 
 func TestGetFracIndex(t *testing.T) {
-	t.Parallel()
 	testCases := []struct {
 		str         string
 		expectIndex int
@@ -1787,7 +1749,6 @@ func TestGetFracIndex(t *testing.T) {
 }
 
 func TestTimeOverflow(t *testing.T) {
-	t.Parallel()
 	sc := mock.NewContext().GetSessionVars().StmtCtx
 	sc.IgnoreZeroInDate = true
 	table := []struct {
@@ -1821,7 +1782,6 @@ func TestTimeOverflow(t *testing.T) {
 }
 
 func TestTruncateFrac(t *testing.T) {
-	t.Parallel()
 	cols := []struct {
 		input  time.Time
 		fsp    int8
@@ -1839,7 +1799,6 @@ func TestTruncateFrac(t *testing.T) {
 }
 
 func TestTimeSub(t *testing.T) {
-	t.Parallel()
 	tbl := []struct {
 		Arg1 string
 		Arg2 string
@@ -1866,7 +1825,6 @@ func TestTimeSub(t *testing.T) {
 }
 
 func TestCheckMonthDay(t *testing.T) {
-	t.Parallel()
 	dates := []struct {
 		date        types.CoreTime
 		isValidDate bool
@@ -1903,7 +1861,6 @@ func TestCheckMonthDay(t *testing.T) {
 }
 
 func TestFormatIntWidthN(t *testing.T) {
-	t.Parallel()
 	cases := []struct {
 		num    int
 		width  int
@@ -1926,7 +1883,6 @@ func TestFormatIntWidthN(t *testing.T) {
 }
 
 func TestFromGoTime(t *testing.T) {
-	t.Parallel()
 	// Test rounding of nanosecond to millisecond.
 	cases := []struct {
 		input string
@@ -1956,7 +1912,6 @@ func TestFromGoTime(t *testing.T) {
 }
 
 func TestGetTimezone(t *testing.T) {
-	t.Parallel()
 	cases := []struct {
 		input    string
 		idx      int
@@ -1985,7 +1940,6 @@ func TestGetTimezone(t *testing.T) {
 }
 
 func TestParseWithTimezone(t *testing.T) {
-	t.Parallel()
 	getTZ := func(tzSign string, tzHour, tzMinue int) *time.Location {
 		offset := tzHour*60*60 + tzMinue*60
 		if tzSign == "-" {
diff --git a/util/admin/admin_integration_test.go b/util/admin/admin_integration_test.go
index 056c6c826b5d8..a6000c73fecc7 100644
--- a/util/admin/admin_integration_test.go
+++ b/util/admin/admin_integration_test.go
@@ -23,8 +23,6 @@ import (
 )
 
 func TestAdminCheckTable(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
@@ -77,8 +75,6 @@ func TestAdminCheckTable(t *testing.T) {
 }
 
 func TestAdminCheckTableClusterIndex(t *testing.T) {
-	t.Parallel()
-
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
 
diff --git a/util/admin/admin_test.go b/util/admin/admin_test.go
index 07fb1be85e17f..72ff15413d935 100644
--- a/util/admin/admin_test.go
+++ b/util/admin/admin_test.go
@@ -28,8 +28,6 @@ import (
 )
 
 func TestGetDDLInfo(t *testing.T) {
-	t.Parallel()
-
 	store, clean := newMockStore(t)
 	defer clean()
 
@@ -79,8 +77,6 @@ func TestGetDDLInfo(t *testing.T) {
 }
 
 func TestGetDDLJobs(t *testing.T) {
-	t.Parallel()
-
 	store, clean := newMockStore(t)
 	defer clean()
 
@@ -134,8 +130,6 @@ func TestGetDDLJobs(t *testing.T) {
 }
 
 func TestGetDDLJobsIsSort(t *testing.T) {
-	t.Parallel()
-
 	store, clean := newMockStore(t)
 	defer clean()
 
@@ -165,8 +159,6 @@ func TestGetDDLJobsIsSort(t *testing.T) {
 }
 
 func TestCancelJobs(t *testing.T) {
-	t.Parallel()
-
 	store, clean := newMockStore(t)
 	defer clean()
 
@@ -280,8 +272,6 @@ func TestCancelJobs(t *testing.T) {
 }
 
 func TestGetHistoryDDLJobs(t *testing.T) {
-	t.Parallel()
-
 	store, clean := newMockStore(t)
 	defer clean()
 
@@ -340,8 +330,6 @@ func TestGetHistoryDDLJobs(t *testing.T) {
 }
 
 func TestIsJobRollbackable(t *testing.T) {
-	t.Parallel()
-
 	cases := []struct {
 		tp     model.ActionType
 		state  model.SchemaState
@@ -364,8 +352,6 @@ func TestIsJobRollbackable(t *testing.T) {
 }
 
 func TestError(t *testing.T) {
-	t.Parallel()
-
 	kvErrs := []*terror.Error{
 		ErrDataInConsistent,
 		ErrDDLJobNotFound,
diff --git a/util/arena/arena_test.go b/util/arena/arena_test.go
index 696afc5e594af..e81dd55dc29aa 100644
--- a/util/arena/arena_test.go
+++ b/util/arena/arena_test.go
@@ -28,8 +28,6 @@ const (
 )
 
 func TestSimpleArenaAllocator(t *testing.T) {
-	t.Parallel()
-
 	arena := NewAllocator(arenaCap)
 	slice := arena.Alloc(allocCapSmall)
 	assert.Equal(t, allocCapSmall, arena.off)
@@ -57,7 +55,6 @@ func TestSimpleArenaAllocator(t *testing.T) {
 }
 
 func TestStdAllocator(t *testing.T) {
-	t.Parallel()
 	slice := StdAllocator.Alloc(allocCapMedium)
 	assert.Len(t, slice, 0)
 	assert.Equal(t, allocCapMedium, cap(slice))
diff --git a/util/bitmap/concurrent_test.go b/util/bitmap/concurrent_test.go
index 41e0c4291f6bc..958fe57b20d23 100644
--- a/util/bitmap/concurrent_test.go
+++ b/util/bitmap/concurrent_test.go
@@ -23,8 +23,6 @@ import (
 )
 
 func TestConcurrentBitmapSet(t *testing.T) {
-	t.Parallel()
-
 	const loopCount = 1000
 	const interval = 2
 
@@ -51,8 +49,6 @@ func TestConcurrentBitmapSet(t *testing.T) {
 // TestConcurrentBitmapUniqueSetter checks if isSetter is unique everytime
 // when a bit is set.
 func TestConcurrentBitmapUniqueSetter(t *testing.T) {
-	t.Parallel()
-
 	const loopCount = 10000
 	const competitorsPerSet = 50
 
diff --git a/util/checksum/checksum_test.go b/util/checksum/checksum_test.go
index e8fe26d816865..b3d205954c7ff 100644
--- a/util/checksum/checksum_test.go
+++ b/util/checksum/checksum_test.go
@@ -25,7 +25,6 @@ import (
 )
 
 func TestChecksumReadAt(t *testing.T) {
-	t.Parallel()
 	f := newFakeFile()
 
 	w := newTestBuff("0123456789", 510)
@@ -56,11 +55,9 @@ func TestChecksumReadAt(t *testing.T) {
 // both the current block and the following block have errors.
 func TestAddOneByte(t *testing.T) {
 	t.Run("unencrypted", func(t *testing.T) {
-		t.Parallel()
 		testAddOneByte(t, false)
 	})
 	t.Run("encrypted", func(t *testing.T) {
-		t.Parallel()
 		testAddOneByte(t, true)
 	})
 }
@@ -99,11 +96,9 @@ func testAddOneByte(t *testing.T, encrypt bool) {
 // both the current block and the following block have errors.
 func TestDeleteOneByte(t *testing.T) {
 	t.Run("unencrypted", func(t *testing.T) {
-		t.Parallel()
 		testDeleteOneByte(t, false)
 	})
 	t.Run("encrypted", func(t *testing.T) {
-		t.Parallel()
 		testDeleteOneByte(t, true)
 	})
 }
@@ -142,11 +137,9 @@ func testDeleteOneByte(t *testing.T, encrypt bool) {
 // only the current block has error.
 func TestModifyOneByte(t *testing.T) {
 	t.Run("unencrypted", func(t *testing.T) {
-		t.Parallel()
 		testModifyOneByte(t, false)
 	})
 	t.Run("encrypted", func(t *testing.T) {
-		t.Parallel()
 		testModifyOneByte(t, true)
 	})
 }
@@ -184,11 +177,9 @@ func testModifyOneByte(t *testing.T, encrypt bool) {
 // TestReadEmptyFile ensures that whether encrypted or not, no error will occur.
 func TestReadEmptyFile(t *testing.T) {
 	t.Run("unencrypted", func(t *testing.T) {
-		t.Parallel()
 		testReadEmptyFile(t, false)
 	})
 	t.Run("encrypted", func(t *testing.T) {
-		t.Parallel()
 		testReadEmptyFile(t, true)
 	})
 }
@@ -221,11 +212,9 @@ func testReadEmptyFile(t *testing.T, encrypt bool) {
 // only the current block has error.
 func TestModifyThreeBytes(t *testing.T) {
 	t.Run("unencrypted", func(t *testing.T) {
-		t.Parallel()
 		testModifyThreeBytes(t, false)
 	})
 	t.Run("encrypted", func(t *testing.T) {
-		t.Parallel()
 		testModifyThreeBytes(t, true)
 	})
 }
@@ -270,11 +259,9 @@ func testModifyThreeBytes(t *testing.T, encrypt bool) {
 // 2. Read all data at once.
 func TestReadDifferentBlockSize(t *testing.T) {
 	t.Run("unencrypted", func(t *testing.T) {
-		t.Parallel()
 		testReadDifferentBlockSize(t, false)
 	})
 	t.Run("encrypted", func(t *testing.T) {
-		t.Parallel()
 		testReadDifferentBlockSize(t, true)
 	})
 }
@@ -328,11 +315,9 @@ func testReadDifferentBlockSize(t *testing.T, encrypt bool) {
 // 2. Write some block and append some block.
 func TestWriteDifferentBlockSize(t *testing.T) {
 	t.Run("unencrypted", func(t *testing.T) {
-		t.Parallel()
 		testWriteDifferentBlockSize(t, false)
 	})
 	t.Run("encrypted", func(t *testing.T) {
-		t.Parallel()
 		testWriteDifferentBlockSize(t, true)
 	})
 }
@@ -393,7 +378,6 @@ func testWriteDifferentBlockSize(t *testing.T, encrypt bool) {
 }
 
 func TestChecksumWriter(t *testing.T) {
-	t.Parallel()
 	f := newFakeFile()
 
 	buf := newTestBuff("0123456789", 100)
@@ -413,7 +397,6 @@ func TestChecksumWriter(t *testing.T) {
 }
 
 func TestChecksumWriterAutoFlush(t *testing.T) {
-	t.Parallel()
 	f := newFakeFile()
 
 	buf := newTestBuff("0123456789", 102)
diff --git a/util/chunk/chunk_test.go b/util/chunk/chunk_test.go
index 1814eca470a43..bb7cb9f9b47c0 100644
--- a/util/chunk/chunk_test.go
+++ b/util/chunk/chunk_test.go
@@ -32,8 +32,6 @@ import (
 )
 
 func TestAppendRow(t *testing.T) {
-	t.Parallel()
-
 	numCols := 6
 	numRows := 10
 	chk := newChunk(8, 8, 0, 0, 40, 0)
@@ -142,8 +140,6 @@ func TestAppendRow(t *testing.T) {
 }
 
 func TestAppendChunk(t *testing.T) {
-	t.Parallel()
-
 	fieldTypes := make([]*types.FieldType, 0, 3)
 	fieldTypes = append(fieldTypes, &types.FieldType{Tp: mysql.TypeFloat})
 	fieldTypes = append(fieldTypes, &types.FieldType{Tp: mysql.TypeVarchar})
@@ -202,8 +198,6 @@ func TestAppendChunk(t *testing.T) {
 }
 
 func TestTruncateTo(t *testing.T) {
-	t.Parallel()
-
 	fieldTypes := make([]*types.FieldType, 0, 3)
 	fieldTypes = append(fieldTypes, &types.FieldType{Tp: mysql.TypeFloat})
 	fieldTypes = append(fieldTypes, &types.FieldType{Tp: mysql.TypeVarchar})
@@ -397,8 +391,6 @@ var allTypes = []*types.FieldType{
 }
 
 func TestCompare(t *testing.T) {
-	t.Parallel()
-
 	chunk := NewChunkWithCapacity(allTypes, 32)
 	for i := 0; i < len(allTypes); i++ {
 		chunk.AppendNull(i)
@@ -485,8 +477,6 @@ func TestCompare(t *testing.T) {
 }
 
 func TestCopyTo(t *testing.T) {
-	t.Parallel()
-
 	chunk := NewChunkWithCapacity(allTypes, 101)
 	for i := 0; i < len(allTypes); i++ {
 		chunk.AppendNull(i)
@@ -541,8 +531,6 @@ func TestCopyTo(t *testing.T) {
 }
 
 func TestGetDecimalDatum(t *testing.T) {
-	t.Parallel()
-
 	datum := types.NewDatum(1.01)
 	decType := types.NewFieldType(mysql.TypeNewDecimal)
 	decType.Flen = 4
@@ -559,8 +547,6 @@ func TestGetDecimalDatum(t *testing.T) {
 }
 
 func TestChunkMemoryUsage(t *testing.T) {
-	t.Parallel()
-
 	fieldTypes := make([]*types.FieldType, 0, 5)
 	fieldTypes = append(fieldTypes, &types.FieldType{Tp: mysql.TypeFloat})
 	fieldTypes = append(fieldTypes, &types.FieldType{Tp: mysql.TypeVarchar})
@@ -617,8 +603,6 @@ func TestChunkMemoryUsage(t *testing.T) {
 }
 
 func TestSwapColumn(t *testing.T) {
-	t.Parallel()
-
 	fieldTypes := make([]*types.FieldType, 0, 2)
 	fieldTypes = append(fieldTypes, &types.FieldType{Tp: mysql.TypeFloat})
 	fieldTypes = append(fieldTypes, &types.FieldType{Tp: mysql.TypeFloat})
@@ -671,8 +655,6 @@ func TestSwapColumn(t *testing.T) {
 }
 
 func TestAppendSel(t *testing.T) {
-	t.Parallel()
-
 	tll := &types.FieldType{Tp: mysql.TypeLonglong}
 	chk := NewChunkWithCapacity([]*types.FieldType{tll}, 1024)
 	sel := make([]int, 0, 1024/2)
@@ -691,8 +673,6 @@ func TestAppendSel(t *testing.T) {
 }
 
 func TestMakeRefTo(t *testing.T) {
-	t.Parallel()
-
 	fieldTypes := make([]*types.FieldType, 0, 2)
 	fieldTypes = append(fieldTypes, &types.FieldType{Tp: mysql.TypeFloat})
 	fieldTypes = append(fieldTypes, &types.FieldType{Tp: mysql.TypeFloat})
@@ -713,8 +693,6 @@ func TestMakeRefTo(t *testing.T) {
 }
 
 func TestToString(t *testing.T) {
-	t.Parallel()
-
 	fieldTypes := make([]*types.FieldType, 0, 4)
 	fieldTypes = append(fieldTypes, &types.FieldType{Tp: mysql.TypeFloat})
 	fieldTypes = append(fieldTypes, &types.FieldType{Tp: mysql.TypeDouble})
@@ -1013,8 +991,6 @@ func benchmarkChunkGrow(t benchChunkGrowCase) func(b *testing.B) {
 }
 
 func TestAppendRows(t *testing.T) {
-	t.Parallel()
-
 	numCols := 6
 	numRows := 10
 	chk := newChunk(8, 8, 0, 0, 40, 0)
diff --git a/util/chunk/chunk_util_test.go b/util/chunk/chunk_util_test.go
index 510b5a482fa94..368f27d08a107 100644
--- a/util/chunk/chunk_util_test.go
+++ b/util/chunk/chunk_util_test.go
@@ -53,8 +53,6 @@ func getChk(isLast3ColTheSame bool) (*Chunk, *Chunk, []bool) {
 }
 
 func TestCopySelectedJoinRows(t *testing.T) {
-	t.Parallel()
-
 	srcChk, dstChk, selected := getChk(true)
 	numRows := srcChk.NumRows()
 	for i := 0; i < numRows; i++ {
@@ -80,8 +78,6 @@ func TestCopySelectedJoinRows(t *testing.T) {
 }
 
 func TestCopySelectedJoinRowsWithoutSameOuters(t *testing.T) {
-	t.Parallel()
-
 	srcChk, dstChk, selected := getChk(false)
 	numRows := srcChk.NumRows()
 	for i := 0; i < numRows; i++ {
@@ -107,8 +103,6 @@ func TestCopySelectedJoinRowsWithoutSameOuters(t *testing.T) {
 }
 
 func TestCopySelectedJoinRowsDirect(t *testing.T) {
-	t.Parallel()
-
 	srcChk, dstChk, selected := getChk(false)
 	numRows := srcChk.NumRows()
 	for i := 0; i < numRows; i++ {
@@ -138,8 +132,6 @@ func TestCopySelectedJoinRowsDirect(t *testing.T) {
 }
 
 func TestCopySelectedVirtualNum(t *testing.T) {
-	t.Parallel()
-
 	// srcChk does not contain columns
 	srcChk := newChunk()
 	srcChk.TruncateTo(3)
diff --git a/util/chunk/codec_test.go b/util/chunk/codec_test.go
index d89b5b80a2fb5..d3ccd87842b67 100644
--- a/util/chunk/codec_test.go
+++ b/util/chunk/codec_test.go
@@ -25,8 +25,6 @@ import (
 )
 
 func TestCodec(t *testing.T) {
-	t.Parallel()
-
 	numCols := 6
 	numRows := 10
 
@@ -77,8 +75,6 @@ func TestCodec(t *testing.T) {
 }
 
 func TestEstimateTypeWidth(t *testing.T) {
-	t.Parallel()
-
 	var colType *types.FieldType
 
 	colType = &types.FieldType{Tp: mysql.TypeLonglong}
diff --git a/util/chunk/column_test.go b/util/chunk/column_test.go
index 69924abfb3d73..5f89f8a9659a6 100644
--- a/util/chunk/column_test.go
+++ b/util/chunk/column_test.go
@@ -28,8 +28,6 @@ import (
 )
 
 func TestColumnCopy(t *testing.T) {
-	t.Parallel()
-
 	col := newFixedLenColumn(8, 10)
 	for i := 0; i < 10; i++ {
 		col.AppendInt64(int64(i))
@@ -44,8 +42,6 @@ func TestColumnCopy(t *testing.T) {
 }
 
 func TestColumnCopyReconstructFixedLen(t *testing.T) {
-	t.Parallel()
-
 	col := NewColumn(types.NewFieldType(mysql.TypeLonglong), 1024)
 	results := make([]int64, 0, 1024)
 	nulls := make([]bool, 0, 1024)
@@ -102,8 +98,6 @@ func TestColumnCopyReconstructFixedLen(t *testing.T) {
 }
 
 func TestColumnCopyReconstructVarLen(t *testing.T) {
-	t.Parallel()
-
 	col := NewColumn(types.NewFieldType(mysql.TypeVarString), 1024)
 	results := make([]string, 0, 1024)
 	nulls := make([]bool, 0, 1024)
@@ -160,8 +154,6 @@ func TestColumnCopyReconstructVarLen(t *testing.T) {
 }
 
 func TestLargeStringColumnOffset(t *testing.T) {
-	t.Parallel()
-
 	numRows := 1
 	col := newVarLenColumn(numRows)
 	// The max-length of a string field can be 6M, a typical batch size for Chunk is 1024, which is 1K.
@@ -171,8 +163,6 @@ func TestLargeStringColumnOffset(t *testing.T) {
 }
 
 func TestI64Column(t *testing.T) {
-	t.Parallel()
-
 	chk := NewChunkWithCapacity([]*types.FieldType{types.NewFieldType(mysql.TypeLonglong)}, 1024)
 	col := chk.Column(0)
 	for i := 0; i < 1024; i++ {
@@ -195,8 +185,6 @@ func TestI64Column(t *testing.T) {
 }
 
 func TestF64Column(t *testing.T) {
-	t.Parallel()
-
 	chk := NewChunkWithCapacity([]*types.FieldType{types.NewFieldType(mysql.TypeDouble)}, 1024)
 	col := chk.Column(0)
 	for i := 0; i < 1024; i++ {
@@ -219,8 +207,6 @@ func TestF64Column(t *testing.T) {
 }
 
 func TestF32Column(t *testing.T) {
-	t.Parallel()
-
 	chk := NewChunkWithCapacity([]*types.FieldType{types.NewFieldType(mysql.TypeFloat)}, 1024)
 	col := chk.Column(0)
 	for i := 0; i < 1024; i++ {
@@ -243,8 +229,6 @@ func TestF32Column(t *testing.T) {
 }
 
 func TestDurationSliceColumn(t *testing.T) {
-	t.Parallel()
-
 	chk := NewChunkWithCapacity([]*types.FieldType{types.NewFieldType(mysql.TypeDuration)}, 1024)
 	col := chk.Column(0)
 	for i := 0; i < 1024; i++ {
@@ -269,8 +253,6 @@ func TestDurationSliceColumn(t *testing.T) {
 }
 
 func TestMyDecimal(t *testing.T) {
-	t.Parallel()
-
 	chk := NewChunkWithCapacity([]*types.FieldType{types.NewFieldType(mysql.TypeNewDecimal)}, 1024)
 	col := chk.Column(0)
 	for i := 0; i < 1024; i++ {
@@ -312,8 +294,6 @@ func TestMyDecimal(t *testing.T) {
 }
 
 func TestStringColumn(t *testing.T) {
-	t.Parallel()
-
 	chk := NewChunkWithCapacity([]*types.FieldType{types.NewFieldType(mysql.TypeVarString)}, 1024)
 	col := chk.Column(0)
 	for i := 0; i < 1024; i++ {
@@ -330,8 +310,6 @@ func TestStringColumn(t *testing.T) {
 }
 
 func TestSetColumn(t *testing.T) {
-	t.Parallel()
-
 	chk := NewChunkWithCapacity([]*types.FieldType{types.NewFieldType(mysql.TypeSet)}, 1024)
 	col := chk.Column(0)
 	for i := 0; i < 1024; i++ {
@@ -352,8 +330,6 @@ func TestSetColumn(t *testing.T) {
 }
 
 func TestJSONColumn(t *testing.T) {
-	t.Parallel()
-
 	chk := NewChunkWithCapacity([]*types.FieldType{types.NewFieldType(mysql.TypeJSON)}, 1024)
 	col := chk.Column(0)
 	for i := 0; i < 1024; i++ {
@@ -374,8 +350,6 @@ func TestJSONColumn(t *testing.T) {
 }
 
 func TestTimeColumn(t *testing.T) {
-	t.Parallel()
-
 	chk := NewChunkWithCapacity([]*types.FieldType{types.NewFieldType(mysql.TypeDatetime)}, 1024)
 	col := chk.Column(0)
 	for i := 0; i < 1024; i++ {
@@ -397,8 +371,6 @@ func TestTimeColumn(t *testing.T) {
 }
 
 func TestDurationColumn(t *testing.T) {
-	t.Parallel()
-
 	chk := NewChunkWithCapacity([]*types.FieldType{types.NewFieldType(mysql.TypeDuration)}, 1024)
 	col := chk.Column(0)
 	for i := 0; i < 1024; i++ {
@@ -416,8 +388,6 @@ func TestDurationColumn(t *testing.T) {
 }
 
 func TestEnumColumn(t *testing.T) {
-	t.Parallel()
-
 	chk := NewChunkWithCapacity([]*types.FieldType{types.NewFieldType(mysql.TypeEnum)}, 1024)
 	col := chk.Column(0)
 	for i := 0; i < 1024; i++ {
@@ -438,8 +408,6 @@ func TestEnumColumn(t *testing.T) {
 }
 
 func TestNullsColumn(t *testing.T) {
-	t.Parallel()
-
 	chk := NewChunkWithCapacity([]*types.FieldType{types.NewFieldType(mysql.TypeLonglong)}, 1024)
 	col := chk.Column(0)
 	for i := 0; i < 1024; i++ {
@@ -464,8 +432,6 @@ func TestNullsColumn(t *testing.T) {
 }
 
 func TestReconstructFixedLen(t *testing.T) {
-	t.Parallel()
-
 	col := NewColumn(types.NewFieldType(mysql.TypeLonglong), 1024)
 	results := make([]int64, 0, 1024)
 	nulls := make([]bool, 0, 1024)
@@ -522,8 +488,6 @@ func TestReconstructFixedLen(t *testing.T) {
 }
 
 func TestReconstructVarLen(t *testing.T) {
-	t.Parallel()
-
 	col := NewColumn(types.NewFieldType(mysql.TypeVarString), 1024)
 	results := make([]string, 0, 1024)
 	nulls := make([]bool, 0, 1024)
@@ -580,8 +544,6 @@ func TestReconstructVarLen(t *testing.T) {
 }
 
 func TestPreAllocInt64(t *testing.T) {
-	t.Parallel()
-
 	col := NewColumn(types.NewFieldType(mysql.TypeLonglong), 128)
 	col.ResizeInt64(256, true)
 	i64s := col.Int64s()
@@ -596,8 +558,6 @@ func TestPreAllocInt64(t *testing.T) {
 }
 
 func TestPreAllocUint64(t *testing.T) {
-	t.Parallel()
-
 	tll := types.NewFieldType(mysql.TypeLonglong)
 	tll.Flag |= mysql.UnsignedFlag
 	col := NewColumn(tll, 128)
@@ -614,8 +574,6 @@ func TestPreAllocUint64(t *testing.T) {
 }
 
 func TestPreAllocFloat32(t *testing.T) {
-	t.Parallel()
-
 	col := newFixedLenColumn(sizeFloat32, 128)
 	col.ResizeFloat32(256, true)
 	f32s := col.Float32s()
@@ -630,8 +588,6 @@ func TestPreAllocFloat32(t *testing.T) {
 }
 
 func TestPreAllocFloat64(t *testing.T) {
-	t.Parallel()
-
 	col := newFixedLenColumn(sizeFloat64, 128)
 	col.ResizeFloat64(256, true)
 	f64s := col.Float64s()
@@ -646,8 +602,6 @@ func TestPreAllocFloat64(t *testing.T) {
 }
 
 func TestPreAllocDecimal(t *testing.T) {
-	t.Parallel()
-
 	col := newFixedLenColumn(sizeMyDecimal, 128)
 	col.ResizeDecimal(256, true)
 	ds := col.Decimals()
@@ -661,8 +615,6 @@ func TestPreAllocDecimal(t *testing.T) {
 }
 
 func TestPreAllocTime(t *testing.T) {
-	t.Parallel()
-
 	col := newFixedLenColumn(sizeTime, 128)
 	col.ResizeTime(256, true)
 	ds := col.Times()
@@ -676,8 +628,6 @@ func TestPreAllocTime(t *testing.T) {
 }
 
 func TestNull(t *testing.T) {
-	t.Parallel()
-
 	col := newFixedLenColumn(sizeFloat64, 32)
 	col.ResizeFloat64(1024, true)
 	require.Equal(t, 1024, col.nullCount())
@@ -710,8 +660,6 @@ func TestNull(t *testing.T) {
 }
 
 func TestSetNulls(t *testing.T) {
-	t.Parallel()
-
 	col := newFixedLenColumn(sizeFloat64, 32)
 	col.ResizeFloat64(1024, true)
 	require.Equal(t, 1024, col.nullCount())
@@ -740,8 +688,6 @@ func TestSetNulls(t *testing.T) {
 }
 
 func TestResizeReserve(t *testing.T) {
-	t.Parallel()
-
 	cI64s := newFixedLenColumn(sizeInt64, 0)
 	require.Zero(t, cI64s.length)
 	for i := 0; i < 100; i++ {
@@ -765,8 +711,6 @@ func TestResizeReserve(t *testing.T) {
 }
 
 func TestGetRaw(t *testing.T) {
-	t.Parallel()
-
 	chk := NewChunkWithCapacity([]*types.FieldType{types.NewFieldType(mysql.TypeFloat)}, 1024)
 	col := chk.Column(0)
 	for i := 0; i < 1024; i++ {
@@ -797,8 +741,6 @@ func TestGetRaw(t *testing.T) {
 }
 
 func TestResize(t *testing.T) {
-	t.Parallel()
-
 	col := NewColumn(types.NewFieldType(mysql.TypeLonglong), 1024)
 	for i := 0; i < 1024; i++ {
 		col.AppendInt64(int64(i))
@@ -979,8 +921,6 @@ func genNullCols(n int) []*Column {
 }
 
 func TestVectorizedNulls(t *testing.T) {
-	t.Parallel()
-
 	for i := 0; i < 256; i++ {
 		cols := genNullCols(4)
 		lCol, rCol := cols[0], cols[1]
@@ -999,8 +939,6 @@ func TestVectorizedNulls(t *testing.T) {
 }
 
 func TestResetColumn(t *testing.T) {
-	t.Parallel()
-
 	col0 := NewColumn(types.NewFieldType(mysql.TypeVarString), 0)
 	col1 := NewColumn(types.NewFieldType(mysql.TypeLonglong), 0)
 
diff --git a/util/chunk/disk_test.go b/util/chunk/disk_test.go
index 20ea805ee5148..fc474f11494df 100644
--- a/util/chunk/disk_test.go
+++ b/util/chunk/disk_test.go
@@ -66,8 +66,6 @@ func initChunks(numChk, numRow int) ([]*Chunk, []*types.FieldType) {
 }
 
 func TestListInDisk(t *testing.T) {
-	t.Parallel()
-
 	numChk, numRow := 2, 2
 	chks, fields := initChunks(numChk, numRow)
 	l := NewListInDisk(fields)
@@ -185,8 +183,6 @@ func checkRow(t *testing.T, row1, row2 Row) {
 }
 
 func testListInDisk(t *testing.T) {
-	t.Parallel()
-
 	numChk, numRow := 10, 1000
 	chks, fields := initChunks(numChk, numRow)
 	lChecksum := NewListInDisk(fields)
@@ -256,8 +252,6 @@ func TestListInDiskWithChecksumAndEncrypt(t *testing.T) {
 // |      |                                          | |                             |
 // +------+------------------------------------------+ +-----------------------------+
 func testReaderWithCache(t *testing.T) {
-	t.Parallel()
-
 	testData := "0123456789"
 	buf := bytes.NewBuffer(nil)
 	for i := 0; i < 102; i++ {
@@ -337,8 +331,6 @@ func testReaderWithCache(t *testing.T) {
 
 // Here we test situations where size of data is small, so no data is flushed to disk.
 func testReaderWithCacheNoFlush(t *testing.T) {
-	t.Parallel()
-
 	testData := "0123456789"
 
 	field := []*types.FieldType{types.NewFieldType(mysql.TypeString)}
diff --git a/util/chunk/iterator_test.go b/util/chunk/iterator_test.go
index 3d947ef2ff076..85e59d23ba153 100644
--- a/util/chunk/iterator_test.go
+++ b/util/chunk/iterator_test.go
@@ -23,8 +23,6 @@ import (
 )
 
 func TestIteratorOnSel(t *testing.T) {
-	t.Parallel()
-
 	fields := []*types.FieldType{types.NewFieldType(mysql.TypeLonglong)}
 	chk := New(fields, 32, 1024)
 	sel := make([]int, 0, 1024)
@@ -52,8 +50,6 @@ func checkEqual(it Iterator, exp []int64, t *testing.T) {
 }
 
 func TestMultiIterator(t *testing.T) {
-	t.Parallel()
-
 	it := NewMultiIterator(NewIterator4Chunk(new(Chunk)))
 	require.Equal(t, it.End(), it.Begin())
 
@@ -97,8 +93,6 @@ func TestMultiIterator(t *testing.T) {
 }
 
 func TestIterator(t *testing.T) {
-	t.Parallel()
-
 	fields := []*types.FieldType{types.NewFieldType(mysql.TypeLonglong)}
 	chk := New(fields, 32, 1024)
 	n := 10
diff --git a/util/chunk/list_test.go b/util/chunk/list_test.go
index c3198d60978fd..63b3eb9ffed0c 100644
--- a/util/chunk/list_test.go
+++ b/util/chunk/list_test.go
@@ -28,8 +28,6 @@ import (
 )
 
 func TestList(t *testing.T) {
-	t.Parallel()
-
 	fields := []*types.FieldType{
 		types.NewFieldType(mysql.TypeLonglong),
 	}
@@ -85,8 +83,6 @@ func TestList(t *testing.T) {
 }
 
 func TestListMemoryUsage(t *testing.T) {
-	t.Parallel()
-
 	fieldTypes := make([]*types.FieldType, 0, 5)
 	fieldTypes = append(fieldTypes, &types.FieldType{Tp: mysql.TypeFloat})
 	fieldTypes = append(fieldTypes, &types.FieldType{Tp: mysql.TypeVarchar})
diff --git a/util/chunk/mutrow_test.go b/util/chunk/mutrow_test.go
index 9c638e867b393..32bef71484f7d 100644
--- a/util/chunk/mutrow_test.go
+++ b/util/chunk/mutrow_test.go
@@ -27,8 +27,6 @@ import (
 )
 
 func TestMutRow(t *testing.T) {
-	t.Parallel()
-
 	mutRow := MutRowFromTypes(allTypes)
 	row := mutRow.ToRow()
 	sc := new(stmtctx.StatementContext)
@@ -92,8 +90,6 @@ func TestMutRow(t *testing.T) {
 }
 
 func TestIssue29947(t *testing.T) {
-	t.Parallel()
-
 	mutRow := MutRowFromTypes(allTypes)
 	nilDatum := types.NewDatum(nil)
 
@@ -171,8 +167,6 @@ func BenchmarkMutRowFromValues(b *testing.B) {
 }
 
 func TestMutRowShallowCopyPartialRow(t *testing.T) {
-	t.Parallel()
-
 	colTypes := make([]*types.FieldType, 0, 3)
 	colTypes = append(colTypes, &types.FieldType{Tp: mysql.TypeVarString})
 	colTypes = append(colTypes, &types.FieldType{Tp: mysql.TypeLonglong})
diff --git a/util/chunk/pool_test.go b/util/chunk/pool_test.go
index b39c317770272..02c9e319b1ab1 100644
--- a/util/chunk/pool_test.go
+++ b/util/chunk/pool_test.go
@@ -23,8 +23,6 @@ import (
 )
 
 func TestNewPool(t *testing.T) {
-	t.Parallel()
-
 	pool := NewPool(1024)
 	require.Equal(t, 1024, pool.initCap)
 	require.NotNil(t, pool.varLenColPool)
@@ -35,8 +33,6 @@ func TestNewPool(t *testing.T) {
 }
 
 func TestPoolGetChunk(t *testing.T) {
-	t.Parallel()
-
 	initCap := 1024
 	pool := NewPool(initCap)
 
@@ -72,8 +68,6 @@ func TestPoolGetChunk(t *testing.T) {
 }
 
 func TestPoolPutChunk(t *testing.T) {
-	t.Parallel()
-
 	initCap := 1024
 	pool := NewPool(initCap)
 
diff --git a/util/chunk/row_container_test.go b/util/chunk/row_container_test.go
index 49d618b0dd96e..553863ddf3141 100644
--- a/util/chunk/row_container_test.go
+++ b/util/chunk/row_container_test.go
@@ -24,8 +24,6 @@ import (
 )
 
 func TestNewRowContainer(t *testing.T) {
-	t.Parallel()
-
 	fields := []*types.FieldType{types.NewFieldType(mysql.TypeLonglong)}
 	rc := NewRowContainer(fields, 1024)
 	require.NotNil(t, rc)
@@ -33,8 +31,6 @@ func TestNewRowContainer(t *testing.T) {
 }
 
 func TestSel(t *testing.T) {
-	t.Parallel()
-
 	fields := []*types.FieldType{types.NewFieldType(mysql.TypeLonglong)}
 	sz := 4
 	rc := NewRowContainer(fields, sz)
@@ -85,8 +81,6 @@ func TestSel(t *testing.T) {
 }
 
 func TestSpillAction(t *testing.T) {
-	t.Parallel()
-
 	sz := 4
 	fields := []*types.FieldType{types.NewFieldType(mysql.TypeLonglong)}
 	rc := NewRowContainer(fields, sz)
@@ -139,8 +133,6 @@ func TestSpillAction(t *testing.T) {
 }
 
 func TestNewSortedRowContainer(t *testing.T) {
-	t.Parallel()
-
 	fields := []*types.FieldType{types.NewFieldType(mysql.TypeLonglong)}
 	rc := NewSortedRowContainer(fields, 1024, nil, nil, nil)
 	require.NotNil(t, rc)
@@ -148,8 +140,6 @@ func TestNewSortedRowContainer(t *testing.T) {
 }
 
 func TestSortedRowContainerSortSpillAction(t *testing.T) {
-	t.Parallel()
-
 	fields := []*types.FieldType{types.NewFieldType(mysql.TypeLonglong)}
 	byItemsDesc := []bool{false}
 	keyColumns := []int{0}
@@ -193,8 +183,6 @@ func TestSortedRowContainerSortSpillAction(t *testing.T) {
 }
 
 func TestRowContainerResetAndAction(t *testing.T) {
-	t.Parallel()
-
 	fields := []*types.FieldType{types.NewFieldType(mysql.TypeLonglong)}
 	sz := 20
 	rc := NewRowContainer(fields, sz)
diff --git a/util/codec/bytes_test.go b/util/codec/bytes_test.go
index 5f108367074b4..eb2dfee922aa0 100644
--- a/util/codec/bytes_test.go
+++ b/util/codec/bytes_test.go
@@ -21,8 +21,6 @@ import (
 )
 
 func TestFastSlowFastReverse(t *testing.T) {
-	t.Parallel()
-
 	if !supportsUnaligned {
 		return
 	}
@@ -35,8 +33,6 @@ func TestFastSlowFastReverse(t *testing.T) {
 }
 
 func TestBytesCodec(t *testing.T) {
-	t.Parallel()
-
 	inputs := []struct {
 		enc  []byte
 		dec  []byte
diff --git a/util/codec/codec_test.go b/util/codec/codec_test.go
index a1480c9745ed2..97eb85695e17b 100644
--- a/util/codec/codec_test.go
+++ b/util/codec/codec_test.go
@@ -35,8 +35,6 @@ import (
 )
 
 func TestCodecKey(t *testing.T) {
-	t.Parallel()
-
 	table := []struct {
 		Input  []types.Datum
 		Expect []types.Datum
@@ -116,8 +114,6 @@ func estimateValuesSize(sc *stmtctx.StatementContext, vals []types.Datum) (int,
 }
 
 func TestCodecKeyCompare(t *testing.T) {
-	t.Parallel()
-
 	table := []struct {
 		Left   []types.Datum
 		Right  []types.Datum
@@ -233,8 +229,6 @@ func TestCodecKeyCompare(t *testing.T) {
 }
 
 func TestNumberCodec(t *testing.T) {
-	t.Parallel()
-
 	tblInt64 := []int64{
 		math.MinInt64,
 		math.MinInt32,
@@ -335,8 +329,6 @@ func TestNumberCodec(t *testing.T) {
 }
 
 func TestNumberOrder(t *testing.T) {
-	t.Parallel()
-
 	tblInt64 := []struct {
 		Arg1 int64
 		Arg2 int64
@@ -405,8 +397,6 @@ func TestNumberOrder(t *testing.T) {
 }
 
 func TestFloatCodec(t *testing.T) {
-	t.Parallel()
-
 	tblFloat := []float64{
 		-1,
 		0,
@@ -465,8 +455,6 @@ func TestFloatCodec(t *testing.T) {
 }
 
 func TestBytes(t *testing.T) {
-	t.Parallel()
-
 	tblBytes := [][]byte{
 		{},
 		{0x00, 0x01},
@@ -545,8 +533,6 @@ func parseDuration(t *testing.T, s string) types.Duration {
 }
 
 func TestTime(t *testing.T) {
-	t.Parallel()
-
 	tbl := []string{
 		"2011-01-01 00:00:00",
 		"2011-01-01 00:00:00",
@@ -594,8 +580,6 @@ func TestTime(t *testing.T) {
 }
 
 func TestDuration(t *testing.T) {
-	t.Parallel()
-
 	tbl := []string{
 		"11:11:11",
 		"00:00:00",
@@ -638,8 +622,6 @@ func TestDuration(t *testing.T) {
 }
 
 func TestDecimal(t *testing.T) {
-	t.Parallel()
-
 	tbl := []string{
 		"1234.00",
 		"1234",
@@ -812,8 +794,6 @@ func TestDecimal(t *testing.T) {
 }
 
 func TestJSON(t *testing.T) {
-	t.Parallel()
-
 	tbl := []string{
 		"1234.00",
 		`{"a": "b"}`,
@@ -843,8 +823,6 @@ func TestJSON(t *testing.T) {
 }
 
 func TestCut(t *testing.T) {
-	t.Parallel()
-
 	table := []struct {
 		Input  []types.Datum
 		Expect []types.Datum
@@ -940,8 +918,6 @@ func TestCut(t *testing.T) {
 }
 
 func TestCutOneError(t *testing.T) {
-	t.Parallel()
-
 	var b []byte
 	_, _, err := CutOne(b)
 	require.Error(t, err)
@@ -954,8 +930,6 @@ func TestCutOneError(t *testing.T) {
 }
 
 func TestSetRawValues(t *testing.T) {
-	t.Parallel()
-
 	sc := &stmtctx.StatementContext{TimeZone: time.Local}
 	datums := types.MakeDatums(1, "abc", 1.1, []byte("def"))
 	rowData, err := EncodeValue(sc, nil, datums...)
@@ -974,8 +948,6 @@ func TestSetRawValues(t *testing.T) {
 }
 
 func TestDecodeOneToChunk(t *testing.T) {
-	t.Parallel()
-
 	sc := &stmtctx.StatementContext{TimeZone: time.Local}
 	datums, tps := datumsForTest(sc)
 	rowCount := 3
@@ -1000,8 +972,6 @@ func TestDecodeOneToChunk(t *testing.T) {
 }
 
 func TestHashGroup(t *testing.T) {
-	t.Parallel()
-
 	sc := &stmtctx.StatementContext{TimeZone: time.Local}
 	tp := types.NewFieldType(mysql.TypeNewDecimal)
 	tps := []*types.FieldType{tp}
@@ -1099,8 +1069,6 @@ func chunkForTest(t *testing.T, sc *stmtctx.StatementContext, datums []types.Dat
 }
 
 func TestDecodeRange(t *testing.T) {
-	t.Parallel()
-
 	_, _, err := DecodeRange(nil, 0, nil, nil)
 	require.Error(t, err)
 
@@ -1167,8 +1135,6 @@ func testHashChunkRowEqual(t *testing.T, a, b interface{}, equal bool) {
 }
 
 func TestHashChunkRow(t *testing.T) {
-	t.Parallel()
-
 	sc := &stmtctx.StatementContext{TimeZone: time.Local}
 	buf := make([]byte, 1)
 	datums, tps := datumsForTest(sc)
@@ -1213,8 +1179,6 @@ func TestHashChunkRow(t *testing.T) {
 }
 
 func TestValueSizeOfSignedInt(t *testing.T) {
-	t.Parallel()
-
 	testCase := []int64{64, 8192, 1048576, 134217728, 17179869184, 2199023255552, 281474976710656, 36028797018963968, 4611686018427387904}
 	var b []byte
 	for _, v := range testCase {
@@ -1240,8 +1204,6 @@ func TestValueSizeOfSignedInt(t *testing.T) {
 }
 
 func TestValueSizeOfUnsignedInt(t *testing.T) {
-	t.Parallel()
-
 	testCase := []uint64{128, 16384, 2097152, 268435456, 34359738368, 4398046511104, 562949953421312, 72057594037927936, 9223372036854775808}
 	var b []byte
 	for _, v := range testCase {
@@ -1257,8 +1219,6 @@ func TestValueSizeOfUnsignedInt(t *testing.T) {
 }
 
 func TestHashChunkColumns(t *testing.T) {
-	t.Parallel()
-
 	sc := &stmtctx.StatementContext{TimeZone: time.Local}
 	buf := make([]byte, 1)
 	datums, tps := datumsForTest(sc)
diff --git a/util/codec/decimal_test.go b/util/codec/decimal_test.go
index 1c01914e90092..77ec77ef92343 100644
--- a/util/codec/decimal_test.go
+++ b/util/codec/decimal_test.go
@@ -22,8 +22,6 @@ import (
 )
 
 func TestDecimalCodec(t *testing.T) {
-	t.Parallel()
-
 	inputs := []struct {
 		Input float64
 	}{
@@ -63,8 +61,6 @@ func TestDecimalCodec(t *testing.T) {
 }
 
 func TestFrac(t *testing.T) {
-	t.Parallel()
-
 	inputs := []struct {
 		Input *types.MyDecimal
 	}{
diff --git a/util/cteutil/storage_test.go b/util/cteutil/storage_test.go
index 2301f03c07807..c64d77d229ef3 100644
--- a/util/cteutil/storage_test.go
+++ b/util/cteutil/storage_test.go
@@ -25,8 +25,6 @@ import (
 )
 
 func TestStorageBasic(t *testing.T) {
-	t.Parallel()
-
 	fields := []*types.FieldType{types.NewFieldType(mysql.TypeLong)}
 	chkSize := 1
 	storage := NewStorageRowContainer(fields, chkSize)
@@ -59,8 +57,6 @@ func TestStorageBasic(t *testing.T) {
 }
 
 func TestOpenAndClose(t *testing.T) {
-	t.Parallel()
-
 	fields := []*types.FieldType{types.NewFieldType(mysql.TypeLong)}
 	chkSize := 1
 	storage := NewStorageRowContainer(fields, chkSize)
@@ -82,8 +78,6 @@ func TestOpenAndClose(t *testing.T) {
 }
 
 func TestAddAndGetChunk(t *testing.T) {
-	t.Parallel()
-
 	fields := []*types.FieldType{types.NewFieldType(mysql.TypeLong)}
 	chkSize := 10
 
@@ -112,8 +106,6 @@ func TestAddAndGetChunk(t *testing.T) {
 }
 
 func TestSpillToDisk(t *testing.T) {
-	t.Parallel()
-
 	fields := []*types.FieldType{types.NewFieldType(mysql.TypeLong)}
 	chkSize := 10
 	storage := NewStorageRowContainer(fields, chkSize)
@@ -169,8 +161,6 @@ func TestSpillToDisk(t *testing.T) {
 }
 
 func TestReopen(t *testing.T) {
-	t.Parallel()
-
 	fields := []*types.FieldType{types.NewFieldType(mysql.TypeLong)}
 	chkSize := 10
 	storage := NewStorageRowContainer(fields, chkSize)
@@ -214,8 +204,6 @@ func TestReopen(t *testing.T) {
 }
 
 func TestSwapData(t *testing.T) {
-	t.Parallel()
-
 	tp1 := []*types.FieldType{types.NewFieldType(mysql.TypeLong)}
 	chkSize := 10
 	storage1 := NewStorageRowContainer(tp1, chkSize)
diff --git a/util/dbterror/terror_test.go b/util/dbterror/terror_test.go
index aae2d9688549d..cdd66b21bd507 100644
--- a/util/dbterror/terror_test.go
+++ b/util/dbterror/terror_test.go
@@ -28,8 +28,6 @@ func genErrMsg(pattern string, a ...interface{}) string {
 }
 
 func TestErrorRedact(t *testing.T) {
-	t.Parallel()
-
 	original := errors.RedactLogEnabled.Load()
 	errors.RedactLogEnabled.Store(true)
 	defer func() { errors.RedactLogEnabled.Store(original) }()
diff --git a/util/encrypt/aes_layer_test.go b/util/encrypt/aes_layer_test.go
index 985e7952ea18e..9846b8fcfbf79 100644
--- a/util/encrypt/aes_layer_test.go
+++ b/util/encrypt/aes_layer_test.go
@@ -73,7 +73,6 @@ func testReadAtWithCase(t *testing.T, testCase readAtTestCase) {
 }
 
 func TestReadAt(t *testing.T) {
-	t.Parallel()
 	ctrCipher1, err := NewCtrCipher()
 	require.NoError(t, err)
 	ctrCipher2, err := NewCtrCipher()
diff --git a/util/encrypt/aes_test.go b/util/encrypt/aes_test.go
index abfef23c89e1f..9dbbb31cc9be5 100644
--- a/util/encrypt/aes_test.go
+++ b/util/encrypt/aes_test.go
@@ -28,7 +28,6 @@ func toHex(buf []byte) string {
 }
 
 func TestPad(t *testing.T) {
-	t.Parallel()
 	p := []byte{0x0A, 0x0B, 0x0C, 0x0D}
 	p, err := PKCS7Pad(p, 8)
 	require.NoError(t, err)
@@ -46,7 +45,6 @@ func TestPad(t *testing.T) {
 }
 
 func TestUnpad(t *testing.T) {
-	t.Parallel()
 	// Valid paddings.
 	p := []byte{0x0A, 0x0B, 0x0C, 0x0D, 0x04, 0x04, 0x04, 0x04}
 	p, err := PKCS7Unpad(p, 8)
@@ -112,7 +110,6 @@ func TestUnpad(t *testing.T) {
 }
 
 func TestAESECB(t *testing.T) {
-	t.Parallel()
 	var commonInput = []byte{
 		0x6b, 0xc1, 0xbe, 0xe2, 0x2e, 0x40, 0x9f, 0x96, 0xe9, 0x3d, 0x7e, 0x11, 0x73, 0x93, 0x17, 0x2a,
 		0xae, 0x2d, 0x8a, 0x57, 0x1e, 0x03, 0xac, 0x9c, 0x9e, 0xb7, 0x6f, 0xac, 0x45, 0xaf, 0x8e, 0x51,
@@ -189,7 +186,6 @@ func TestAESECB(t *testing.T) {
 }
 
 func TestAESEncryptWithECB(t *testing.T) {
-	t.Parallel()
 	tests := []struct {
 		str     string
 		key     string
@@ -222,7 +218,6 @@ func TestAESEncryptWithECB(t *testing.T) {
 }
 
 func TestAESDecryptWithECB(t *testing.T) {
-	t.Parallel()
 	tests := []struct {
 		expect      string
 		key         string
@@ -258,7 +253,6 @@ func TestAESDecryptWithECB(t *testing.T) {
 }
 
 func TestAESEncryptWithCBC(t *testing.T) {
-	t.Parallel()
 	tests := []struct {
 		str     string
 		key     string
@@ -293,7 +287,6 @@ func TestAESEncryptWithCBC(t *testing.T) {
 }
 
 func TestAESEncryptWithOFB(t *testing.T) {
-	t.Parallel()
 	tests := []struct {
 		str     string
 		key     string
@@ -328,7 +321,6 @@ func TestAESEncryptWithOFB(t *testing.T) {
 }
 
 func TestAESDecryptWithOFB(t *testing.T) {
-	t.Parallel()
 	tests := []struct {
 		str     string
 		key     string
@@ -362,7 +354,6 @@ func TestAESDecryptWithOFB(t *testing.T) {
 }
 
 func TestAESEncryptWithCTR(t *testing.T) {
-	t.Parallel()
 	tests := []struct {
 		str     string
 		key     string
@@ -397,7 +388,6 @@ func TestAESEncryptWithCTR(t *testing.T) {
 }
 
 func TestAESDecryptWithCTR(t *testing.T) {
-	t.Parallel()
 	tests := []struct {
 		str     string
 		key     string
@@ -431,7 +421,6 @@ func TestAESDecryptWithCTR(t *testing.T) {
 }
 
 func TestAESDecryptWithCBC(t *testing.T) {
-	t.Parallel()
 	tests := []struct {
 		expect      string
 		key         string
@@ -469,7 +458,6 @@ func TestAESDecryptWithCBC(t *testing.T) {
 }
 
 func TestAESEncryptWithCFB(t *testing.T) {
-	t.Parallel()
 	tests := []struct {
 		str     string
 		key     string
@@ -504,7 +492,6 @@ func TestAESEncryptWithCFB(t *testing.T) {
 }
 
 func TestAESDecryptWithCFB(t *testing.T) {
-	t.Parallel()
 	tests := []struct {
 		str     string
 		key     string
@@ -538,7 +525,6 @@ func TestAESDecryptWithCFB(t *testing.T) {
 }
 
 func TestDeriveKeyMySQL(t *testing.T) {
-	t.Parallel()
 	p := []byte("MySQL=insecure! MySQL=insecure! ")
 	p = DeriveKeyMySQL(p, 16)
 	require.Equal(t, "00000000000000000000000000000000", toHex(p))
diff --git a/util/encrypt/crypt_test.go b/util/encrypt/crypt_test.go
index 8cd9e686cf02d..bfc09ec224ab9 100644
--- a/util/encrypt/crypt_test.go
+++ b/util/encrypt/crypt_test.go
@@ -21,7 +21,6 @@ import (
 )
 
 func TestSQLDecode(t *testing.T) {
-	t.Parallel()
 	tests := []struct {
 		str     string
 		passwd  string
@@ -53,7 +52,6 @@ func TestSQLDecode(t *testing.T) {
 }
 
 func TestSQLEncode(t *testing.T) {
-	t.Parallel()
 	tests := []struct {
 		str     string
 		passwd  string
diff --git a/util/execdetails/execdetails.go b/util/execdetails/execdetails.go
index 4265145c2d66a..ea1e4cda1e746 100644
--- a/util/execdetails/execdetails.go
+++ b/util/execdetails/execdetails.go
@@ -968,7 +968,7 @@ func FormatDuration(d time.Duration) string {
 	if unit == time.Nanosecond {
 		return d.String()
 	}
-	integer := (d / unit) * unit
+	integer := (d / unit) * unit //nolint:durationcheck
 	decimal := float64(d%unit) / float64(unit)
 	if d < 10*unit {
 		decimal = math.Round(decimal*100) / 100
diff --git a/util/execdetails/execdetails_test.go b/util/execdetails/execdetails_test.go
index 468f7dac1f54c..a3a763a271fc7 100644
--- a/util/execdetails/execdetails_test.go
+++ b/util/execdetails/execdetails_test.go
@@ -26,7 +26,6 @@ import (
 )
 
 func TestString(t *testing.T) {
-	t.Parallel()
 	detail := &ExecDetails{
 		CopTime:      time.Second + 3*time.Millisecond,
 		BackoffTime:  time.Second,
@@ -87,7 +86,6 @@ func mockExecutorExecutionSummaryForTiFlash(TimeProcessedNs, NumProducedRows, Nu
 }
 
 func TestCopRuntimeStats(t *testing.T) {
-	t.Parallel()
 	stats := NewRuntimeStatsColl(nil)
 	tableScanID := 1
 	aggID := 2
@@ -140,7 +138,6 @@ func TestCopRuntimeStats(t *testing.T) {
 }
 
 func TestCopRuntimeStatsForTiFlash(t *testing.T) {
-	t.Parallel()
 	stats := NewRuntimeStatsColl(nil)
 	tableScanID := 1
 	aggID := 2
@@ -179,7 +176,6 @@ func TestCopRuntimeStatsForTiFlash(t *testing.T) {
 }
 
 func TestRuntimeStatsWithCommit(t *testing.T) {
-	t.Parallel()
 	commitDetail := &util.CommitDetails{
 		GetCommitTsTime: time.Second,
 		PrewriteTime:    time.Second,
@@ -230,7 +226,6 @@ func TestRuntimeStatsWithCommit(t *testing.T) {
 }
 
 func TestRootRuntimeStats(t *testing.T) {
-	t.Parallel()
 	basic1 := &BasicRuntimeStats{}
 	basic2 := &BasicRuntimeStats{}
 	basic1.Record(time.Second, 20)
@@ -260,7 +255,6 @@ func TestRootRuntimeStats(t *testing.T) {
 }
 
 func TestFormatDurationForExplain(t *testing.T) {
-	t.Parallel()
 	cases := []struct {
 		t string
 		s string
diff --git a/util/expensivequery/expensivequerey_test.go b/util/expensivequery/expensivequerey_test.go
index dc7ab46282f54..8f5c60179694e 100644
--- a/util/expensivequery/expensivequerey_test.go
+++ b/util/expensivequery/expensivequerey_test.go
@@ -32,8 +32,6 @@ func TestMain(m *testing.M) {
 }
 
 func TestLogFormat(t *testing.T) {
-	t.Parallel()
-
 	mem := new(memory.Tracker)
 	mem.Consume(1<<30 + 1<<29 + 1<<28 + 1<<27)
 	info := &util.ProcessInfo{
diff --git a/util/fastrand/random_test.go b/util/fastrand/random_test.go
index 57587a63c6f5b..a89984eb4464d 100644
--- a/util/fastrand/random_test.go
+++ b/util/fastrand/random_test.go
@@ -22,8 +22,6 @@ import (
 )
 
 func TestRand(t *testing.T) {
-	t.Parallel()
-
 	x := Uint32N(1024)
 	require.Less(t, x, uint32(1024))
 	y := Uint64N(1 << 63)
diff --git a/util/format/format_test.go b/util/format/format_test.go
index efe33b75f11c8..d96492973afae 100644
--- a/util/format/format_test.go
+++ b/util/format/format_test.go
@@ -31,8 +31,6 @@ func checkFormat(t *testing.T, f Formatter, buf *bytes.Buffer, str, expect strin
 }
 
 func TestFormat(t *testing.T) {
-	t.Parallel()
-
 	str := "abc%d%%e%i\nx\ny\n%uz\n"
 	buf := &bytes.Buffer{}
 	f := IndentFormatter(buf, "\t")
diff --git a/util/generatedexpr/gen_expr_test.go b/util/generatedexpr/gen_expr_test.go
index ca00e6349749c..484453466e7eb 100644
--- a/util/generatedexpr/gen_expr_test.go
+++ b/util/generatedexpr/gen_expr_test.go
@@ -24,8 +24,6 @@ import (
 )
 
 func TestParseExpression(t *testing.T) {
-	t.Parallel()
-
 	node, err := ParseExpression("json_extract(a, '$.a')")
 	require.NoError(t, err)
 	require.Equal(t, "json_extract", node.(*ast.FuncCallExpr).FnName.L)
diff --git a/util/kvcache/simple_lru_test.go b/util/kvcache/simple_lru_test.go
index 3498be84174b3..009971a640e93 100644
--- a/util/kvcache/simple_lru_test.go
+++ b/util/kvcache/simple_lru_test.go
@@ -46,8 +46,6 @@ func newMockHashKey(key int64) *mockCacheKey {
 }
 
 func TestPut(t *testing.T) {
-	t.Parallel()
-
 	maxMem, err := memory.MemTotal()
 	require.NoError(t, err)
 
@@ -121,7 +119,6 @@ func TestPut(t *testing.T) {
 }
 
 func TestZeroQuota(t *testing.T) {
-	t.Parallel()
 	lru := NewSimpleLRUCache(100, 0, 0)
 	require.Equal(t, uint(100), lru.capacity)
 
@@ -138,7 +135,6 @@ func TestZeroQuota(t *testing.T) {
 }
 
 func TestOOMGuard(t *testing.T) {
-	t.Parallel()
 	maxMem, err := memory.MemTotal()
 	require.NoError(t, err)
 
@@ -164,7 +160,6 @@ func TestOOMGuard(t *testing.T) {
 }
 
 func TestGet(t *testing.T) {
-	t.Parallel()
 	maxMem, err := memory.MemTotal()
 	require.NoError(t, err)
 
@@ -208,7 +203,6 @@ func TestGet(t *testing.T) {
 }
 
 func TestDelete(t *testing.T) {
-	t.Parallel()
 	maxMem, err := memory.MemTotal()
 	require.NoError(t, err)
 
@@ -238,7 +232,6 @@ func TestDelete(t *testing.T) {
 }
 
 func TestDeleteAll(t *testing.T) {
-	t.Parallel()
 	maxMem, err := memory.MemTotal()
 	require.NoError(t, err)
 
@@ -265,7 +258,6 @@ func TestDeleteAll(t *testing.T) {
 }
 
 func TestValues(t *testing.T) {
-	t.Parallel()
 	maxMem, err := memory.MemTotal()
 	require.NoError(t, err)
 
@@ -288,7 +280,6 @@ func TestValues(t *testing.T) {
 }
 
 func TestPutProfileName(t *testing.T) {
-	t.Parallel()
 	lru := NewSimpleLRUCache(3, 0, 10)
 	require.Equal(t, uint(3), lru.capacity)
 	tem := reflect.TypeOf(*lru)
diff --git a/util/math/math_test.go b/util/math/math_test.go
index 39d3e4241d7e1..6c180e45bc481 100644
--- a/util/math/math_test.go
+++ b/util/math/math_test.go
@@ -24,7 +24,6 @@ import (
 
 func TestStrLenOfUint64Fast(t *testing.T) {
 	t.Run("RandomInput", func(t *testing.T) {
-		t.Parallel()
 		for i := 0; i < 1000000; i++ {
 			num := rand.Uint64()
 			expected := len(strconv.FormatUint(num, 10))
@@ -34,7 +33,6 @@ func TestStrLenOfUint64Fast(t *testing.T) {
 	})
 
 	t.Run("ManualInput", func(t *testing.T) {
-		t.Parallel()
 		nums := [22]uint64{0,
 			1, 12, 123, 1234, 12345,
 			123456, 1234567, 12345678, 123456789, 1234567890,
diff --git a/util/math/rand_test.go b/util/math/rand_test.go
index 70f6bac105e10..d262d676478d6 100644
--- a/util/math/rand_test.go
+++ b/util/math/rand_test.go
@@ -22,8 +22,6 @@ import (
 )
 
 func TestRandWithTime(t *testing.T) {
-	t.Parallel()
-
 	rng1 := NewWithTime()
 	// NOTE: On windows platform, this Sleep is necessary. Because time.Now() is
 	// imprecise, calling UnixNano() twice returns the same value. We have to make
@@ -42,8 +40,6 @@ func TestRandWithTime(t *testing.T) {
 }
 
 func TestRandWithSeed(t *testing.T) {
-	t.Parallel()
-
 	tests := [4]struct {
 		seed  int64
 		once  float64
@@ -62,8 +58,6 @@ func TestRandWithSeed(t *testing.T) {
 }
 
 func TestRandWithSeed1AndSeed2(t *testing.T) {
-	t.Parallel()
-
 	seed1 := uint32(10000000)
 	seed2 := uint32(1000000)
 
diff --git a/util/memory/tracker_test.go b/util/memory/tracker_test.go
index 1fe8b3aeb63df..f0ce70b55f56c 100644
--- a/util/memory/tracker_test.go
+++ b/util/memory/tracker_test.go
@@ -29,8 +29,6 @@ import (
 )
 
 func TestSetLabel(t *testing.T) {
-	t.Parallel()
-
 	tracker := NewTracker(1, -1)
 	require.Equal(t, 1, tracker.label)
 	require.Equal(t, int64(0), tracker.BytesConsumed())
@@ -73,8 +71,6 @@ func TestConsume(t *testing.T) {
 }
 
 func TestOOMAction(t *testing.T) {
-	t.Parallel()
-
 	tracker := NewTracker(1, 100)
 	// make sure no panic here.
 	tracker.Consume(10000)
@@ -144,8 +140,6 @@ func (a *mockAction) GetPriority() int64 {
 }
 
 func TestAttachTo(t *testing.T) {
-	t.Parallel()
-
 	oldParent := NewTracker(1, -1)
 	newParent := NewTracker(2, -1)
 	child := NewTracker(3, -1)
@@ -168,8 +162,6 @@ func TestAttachTo(t *testing.T) {
 }
 
 func TestDetach(t *testing.T) {
-	t.Parallel()
-
 	parent := NewTracker(1, -1)
 	child := NewTracker(2, -1)
 	child.Consume(100)
@@ -187,8 +179,6 @@ func TestDetach(t *testing.T) {
 }
 
 func TestReplaceChild(t *testing.T) {
-	t.Parallel()
-
 	oldChild := NewTracker(1, -1)
 	oldChild.Consume(100)
 	newChild := NewTracker(2, -1)
@@ -231,8 +221,6 @@ func TestReplaceChild(t *testing.T) {
 }
 
 func TestToString(t *testing.T) {
-	t.Parallel()
-
 	parent := NewTracker(1, -1)
 	child1 := NewTracker(2, 1000)
 	child2 := NewTracker(3, -1)
@@ -270,8 +258,6 @@ func TestToString(t *testing.T) {
 }
 
 func TestMaxConsumed(t *testing.T) {
-	t.Parallel()
-
 	r := NewTracker(1, -1)
 	c1 := NewTracker(2, -1)
 	c2 := NewTracker(3, -1)
@@ -299,8 +285,6 @@ func TestMaxConsumed(t *testing.T) {
 }
 
 func TestGlobalTracker(t *testing.T) {
-	t.Parallel()
-
 	r := NewGlobalTracker(1, -1)
 	c1 := NewTracker(2, -1)
 	c2 := NewTracker(3, -1)
@@ -388,8 +372,6 @@ func parseByte(str string) (int64, error) {
 }
 
 func TestFormatBytesWithPrune(t *testing.T) {
-	t.Parallel()
-
 	cases := []struct {
 		b string
 		s string
@@ -435,14 +417,10 @@ func TestFormatBytesWithPrune(t *testing.T) {
 }
 
 func TestErrorCode(t *testing.T) {
-	t.Parallel()
-
 	require.Equal(t, errno.ErrMemExceedThreshold, int(terror.ToSQLError(errMemExceedThreshold).Code))
 }
 
 func TestOOMActionPriority(t *testing.T) {
-	t.Parallel()
-
 	tracker := NewTracker(1, 100)
 	// make sure no panic here.
 	tracker.Consume(10000)
diff --git a/util/misc_test.go b/util/misc_test.go
index 73e56c82d9dbb..11b169669816a 100644
--- a/util/misc_test.go
+++ b/util/misc_test.go
@@ -34,7 +34,6 @@ import (
 
 func TestRunWithRetry(t *testing.T) {
 	t.Run("success", func(t *testing.T) {
-		t.Parallel()
 		cnt := 0
 		err := RunWithRetry(3, 1, func() (bool, error) {
 			cnt++
@@ -48,7 +47,6 @@ func TestRunWithRetry(t *testing.T) {
 	})
 
 	t.Run("retry exceeds", func(t *testing.T) {
-		t.Parallel()
 		cnt := 0
 		err := RunWithRetry(3, 1, func() (bool, error) {
 			cnt++
@@ -62,7 +60,6 @@ func TestRunWithRetry(t *testing.T) {
 	})
 
 	t.Run("failed result", func(t *testing.T) {
-		t.Parallel()
 		cnt := 0
 		err := RunWithRetry(3, 1, func() (bool, error) {
 			cnt++
@@ -77,8 +74,6 @@ func TestRunWithRetry(t *testing.T) {
 }
 
 func TestX509NameParseMatch(t *testing.T) {
-	t.Parallel()
-
 	assert.Equal(t, "", X509NameOnline(pkix.Name{}))
 
 	check := pkix.Name{
@@ -97,13 +92,11 @@ func TestX509NameParseMatch(t *testing.T) {
 }
 
 func TestBasicFuncGetStack(t *testing.T) {
-	t.Parallel()
 	b := GetStack()
 	assert.Less(t, len(b), 4096)
 }
 
 func TestBasicFuncWithRecovery(t *testing.T) {
-	t.Parallel()
 	var recovery interface{}
 	WithRecovery(func() {
 		panic("test")
@@ -114,20 +107,17 @@ func TestBasicFuncWithRecovery(t *testing.T) {
 }
 
 func TestBasicFuncSyntaxError(t *testing.T) {
-	t.Parallel()
 	assert.Nil(t, SyntaxError(nil))
 	assert.True(t, terror.ErrorEqual(SyntaxError(errors.New("test")), parser.ErrParse))
 	assert.True(t, terror.ErrorEqual(SyntaxError(parser.ErrSyntax.GenWithStackByArgs()), parser.ErrSyntax))
 }
 
 func TestBasicFuncSyntaxWarn(t *testing.T) {
-	t.Parallel()
 	assert.Nil(t, SyntaxWarn(nil))
 	assert.True(t, terror.ErrorEqual(SyntaxWarn(errors.New("test")), parser.ErrParse))
 }
 
 func TestBasicFuncProcessInfo(t *testing.T) {
-	t.Parallel()
 	pi := ProcessInfo{
 		ID:      1,
 		User:    "test",
@@ -161,7 +151,6 @@ func TestBasicFuncProcessInfo(t *testing.T) {
 }
 
 func TestBasicFuncRandomBuf(t *testing.T) {
-	t.Parallel()
 	buf := fastrand.Buf(5)
 	assert.Len(t, buf, 5)
 	assert.False(t, bytes.Contains(buf, []byte("$")))
@@ -169,7 +158,6 @@ func TestBasicFuncRandomBuf(t *testing.T) {
 }
 
 func TestToPB(t *testing.T) {
-	t.Parallel()
 	column := &model.ColumnInfo{
 		ID:           1,
 		Name:         model.NewCIStr("c"),
@@ -195,7 +183,6 @@ func TestToPB(t *testing.T) {
 }
 
 func TestComposeURL(t *testing.T) {
-	t.Parallel()
 	// TODO Setup config for TLS and verify https protocol output
 	assert.Equal(t, ComposeURL("server.example.com", ""), "http://server.example.com")
 	assert.Equal(t, ComposeURL("httpserver.example.com", ""), "http://httpserver.example.com")
diff --git a/util/mock/mock_test.go b/util/mock/mock_test.go
index 764fc9c2f32f1..8d2af9fe6575a 100644
--- a/util/mock/mock_test.go
+++ b/util/mock/mock_test.go
@@ -29,8 +29,6 @@ func (k contextKeyType) String() string {
 const contextKey contextKeyType = 0
 
 func TestContext(t *testing.T) {
-	t.Parallel()
-
 	ctx := NewContext()
 
 	ctx.SetValue(contextKey, 1)
diff --git a/util/mvmap/mvmap_test.go b/util/mvmap/mvmap_test.go
index f1d8b5ebc9cdf..dbc5214925ec2 100644
--- a/util/mvmap/mvmap_test.go
+++ b/util/mvmap/mvmap_test.go
@@ -23,8 +23,6 @@ import (
 )
 
 func TestMVMap(t *testing.T) {
-	t.Parallel()
-
 	m := NewMVMap()
 	m.Put([]byte("abc"), []byte("abc1"))
 	m.Put([]byte("abc"), []byte("abc2"))
@@ -52,8 +50,6 @@ func TestMVMap(t *testing.T) {
 }
 
 func TestFNVHash(t *testing.T) {
-	t.Parallel()
-
 	b := []byte{0xcb, 0xf2, 0x9c, 0xe4, 0x84, 0x22, 0x23, 0x25}
 	sum1 := fnvHash64(b)
 	hash := fnv.New64()
diff --git a/util/parser/ast_test.go b/util/parser/ast_test.go
index 3154474689e60..6c10efc3020b0 100644
--- a/util/parser/ast_test.go
+++ b/util/parser/ast_test.go
@@ -24,8 +24,6 @@ import (
 )
 
 func TestSimpleCases(t *testing.T) {
-	t.Parallel()
-
 	tests := []struct {
 		sql string
 		db  string
diff --git a/util/parser/parser_test.go b/util/parser/parser_test.go
index 6fe69d9ce4b6b..4a05fd0146179 100644
--- a/util/parser/parser_test.go
+++ b/util/parser/parser_test.go
@@ -22,8 +22,6 @@ import (
 )
 
 func TestSpace(t *testing.T) {
-	t.Parallel()
-
 	okTable := []struct {
 		Times    int
 		Input    string
@@ -57,8 +55,6 @@ func TestSpace(t *testing.T) {
 }
 
 func TestDigit(t *testing.T) {
-	t.Parallel()
-
 	okTable := []struct {
 		Times          int
 		Input          string
@@ -98,8 +94,6 @@ func TestDigit(t *testing.T) {
 }
 
 func TestNumber(t *testing.T) {
-	t.Parallel()
-
 	okTable := []struct {
 		Input        string
 		ExpectedNum  int
@@ -136,8 +130,6 @@ func TestNumber(t *testing.T) {
 }
 
 func TestCharAndAnyChar(t *testing.T) {
-	t.Parallel()
-
 	okTable := []struct {
 		Char     byte
 		Input    string
diff --git a/util/plancodec/codec_test.go b/util/plancodec/codec_test.go
index 1b8af9f0b14dc..ed1a8fe2f4833 100644
--- a/util/plancodec/codec_test.go
+++ b/util/plancodec/codec_test.go
@@ -29,7 +29,6 @@ type encodeTaskTypeCase struct {
 }
 
 func TestEncodeTaskType(t *testing.T) {
-	t.Parallel()
 	cases := []encodeTaskTypeCase{
 		{true, kv.UnSpecified, "0", "root"},
 		{false, kv.TiKV, "1_0", "cop[tikv]"},
@@ -52,8 +51,6 @@ func TestEncodeTaskType(t *testing.T) {
 }
 
 func TestDecodeDiscardPlan(t *testing.T) {
-	t.Parallel()
-
 	plan, err := DecodePlan(PlanDiscardedEncoded)
 	require.NoError(t, err)
 	require.Equal(t, planDiscardedDecoded, plan)
diff --git a/util/plancodec/id_test.go b/util/plancodec/id_test.go
index 8c2590f5e28b9..f97939e4cc14f 100644
--- a/util/plancodec/id_test.go
+++ b/util/plancodec/id_test.go
@@ -22,7 +22,6 @@ import (
 
 func TestPlanIDChanged(t *testing.T) {
 	// Attention: for compatibility, shouldn't modify the below test, you can only add test when add new plan ID.
-	t.Parallel()
 	testCases := []struct {
 		Value    int
 		Expected int
diff --git a/util/prefix_helper_test.go b/util/prefix_helper_test.go
index 279ac86f64e97..94e04add5669d 100644
--- a/util/prefix_helper_test.go
+++ b/util/prefix_helper_test.go
@@ -34,7 +34,6 @@ const (
 )
 
 func TestPrefix(t *testing.T) {
-	t.Parallel()
 	s, err := mockstore.NewMockStore()
 	require.Nil(t, err)
 	defer func() {
@@ -75,7 +74,6 @@ func TestPrefix(t *testing.T) {
 }
 
 func TestPrefixFilter(t *testing.T) {
-	t.Parallel()
 	rowKey := []byte(`test@#$%l(le[0]..prefix) 2uio`)
 	rowKey[8] = 0x00
 	rowKey[9] = 0x00
diff --git a/util/printer/printer_test.go b/util/printer/printer_test.go
index 38c73fabbd7eb..0a5c3afc5fedc 100644
--- a/util/printer/printer_test.go
+++ b/util/printer/printer_test.go
@@ -21,7 +21,6 @@ import (
 )
 
 func TestPrintResult(t *testing.T) {
-	t.Parallel()
 	cols := []string{"col1", "col2", "col3"}
 	datas := [][]string{{"11"}, {"21", "22", "23"}}
 	result, ok := GetPrintResult(cols, datas)
diff --git a/util/processinfo_test.go b/util/processinfo_test.go
index 8edaeb7f4e6a2..ee5d01c5e5d92 100644
--- a/util/processinfo_test.go
+++ b/util/processinfo_test.go
@@ -23,7 +23,6 @@ import (
 )
 
 func TestGlobalConnID(t *testing.T) {
-	t.Parallel()
 	originCfg := config.GetGlobalConfig()
 	newCfg := *originCfg
 	newCfg.Experimental.EnableGlobalKill = true
diff --git a/util/profile/flamegraph_test.go b/util/profile/flamegraph_test.go
index dfc83d3b27654..f26c45589be46 100644
--- a/util/profile/flamegraph_test.go
+++ b/util/profile/flamegraph_test.go
@@ -26,8 +26,6 @@ import (
 )
 
 func TestProfileToDatum(t *testing.T) {
-	t.Parallel()
-
 	file, err := os.Open("testdata/test.pprof")
 	require.Nil(t, err)
 	defer func() {
diff --git a/util/profile/profile_test.go b/util/profile/profile_test.go
index e8cff9c8daaaa..e9fbfa0c776a4 100644
--- a/util/profile/profile_test.go
+++ b/util/profile/profile_test.go
@@ -28,7 +28,6 @@ import (
 )
 
 func TestProfiles(t *testing.T) {
-	t.Parallel()
 	var err error
 	var store kv.Storage
 	var dom *domain.Domain
diff --git a/util/ranger/ranger_test.go b/util/ranger/ranger_test.go
index d18bf80849529..03de4f42c2eea 100644
--- a/util/ranger/ranger_test.go
+++ b/util/ranger/ranger_test.go
@@ -48,7 +48,6 @@ func newDomainStoreWithBootstrap(t *testing.T) (*domain.Domain, kv.Storage, erro
 }
 
 func TestTableRange(t *testing.T) {
-	t.Parallel()
 	dom, store, err := newDomainStoreWithBootstrap(t)
 	defer func() {
 		dom.Close()
@@ -307,7 +306,6 @@ func TestTableRange(t *testing.T) {
 
 // for issue #6661
 func TestIndexRangeForUnsignedAndOverflow(t *testing.T) {
-	t.Parallel()
 	dom, store, err := newDomainStoreWithBootstrap(t)
 	defer func() {
 		dom.Close()
@@ -864,7 +862,6 @@ func TestColumnRange(t *testing.T) {
 }
 
 func TestIndexRangeEliminatedProjection(t *testing.T) {
-	t.Parallel()
 	dom, store, err := newDomainStoreWithBootstrap(t)
 	defer func() {
 		dom.Close()
@@ -921,7 +918,6 @@ func TestCompIndexInExprCorrCol(t *testing.T) {
 }
 
 func TestIndexStringIsTrueRange(t *testing.T) {
-	t.Parallel()
 	dom, store, err := newDomainStoreWithBootstrap(t)
 	defer func() {
 		dom.Close()
@@ -952,7 +948,6 @@ func TestIndexStringIsTrueRange(t *testing.T) {
 }
 
 func TestCompIndexDNFMatch(t *testing.T) {
-	t.Parallel()
 	dom, store, err := newDomainStoreWithBootstrap(t)
 	defer func() {
 		dom.Close()
@@ -985,7 +980,6 @@ func TestCompIndexDNFMatch(t *testing.T) {
 }
 
 func TestCompIndexMultiColDNF1(t *testing.T) {
-	t.Parallel()
 	dom, store, err := newDomainStoreWithBootstrap(t)
 	defer func() {
 		dom.Close()
@@ -1019,7 +1013,6 @@ func TestCompIndexMultiColDNF1(t *testing.T) {
 }
 
 func TestCompIndexMultiColDNF2(t *testing.T) {
-	t.Parallel()
 	dom, store, err := newDomainStoreWithBootstrap(t)
 	defer func() {
 		dom.Close()
@@ -1053,7 +1046,6 @@ func TestCompIndexMultiColDNF2(t *testing.T) {
 }
 
 func TestPrefixIndexMultiColDNF(t *testing.T) {
-	t.Parallel()
 	dom, store, err := newDomainStoreWithBootstrap(t)
 	defer func() {
 		dom.Close()
@@ -1089,7 +1081,6 @@ func TestPrefixIndexMultiColDNF(t *testing.T) {
 }
 
 func TestIndexRangeForBit(t *testing.T) {
-	t.Parallel()
 	dom, store, err := newDomainStoreWithBootstrap(t)
 	defer func() {
 		dom.Close()
@@ -1128,7 +1119,6 @@ func TestIndexRangeForBit(t *testing.T) {
 }
 
 func TestIndexRangeForYear(t *testing.T) {
-	t.Parallel()
 	dom, store, err := newDomainStoreWithBootstrap(t)
 	defer func() {
 		dom.Close()
@@ -1291,7 +1281,6 @@ func TestIndexRangeForYear(t *testing.T) {
 
 // For https://github.com/pingcap/tidb/issues/22032
 func TestPrefixIndexRangeScan(t *testing.T) {
-	t.Parallel()
 	dom, store, err := newDomainStoreWithBootstrap(t)
 	defer func() {
 		dom.Close()
@@ -1363,7 +1352,6 @@ func TestPrefixIndexRangeScan(t *testing.T) {
 }
 
 func TestIndexRangeForDecimal(t *testing.T) {
-	t.Parallel()
 	dom, store, err := newDomainStoreWithBootstrap(t)
 	defer func() {
 		dom.Close()
@@ -1397,7 +1385,6 @@ func TestIndexRangeForDecimal(t *testing.T) {
 }
 
 func TestPrefixIndexAppendPointRanges(t *testing.T) {
-	t.Parallel()
 	dom, store, err := newDomainStoreWithBootstrap(t)
 	defer func() {
 		dom.Close()
diff --git a/util/ranger/types.go b/util/ranger/types.go
index 2e8cc1dc6120d..f2bf561f6a3cf 100644
--- a/util/ranger/types.go
+++ b/util/ranger/types.go
@@ -119,8 +119,8 @@ func (ran *Range) IsPointNonNullable(sctx sessionctx.Context) bool {
 
 // IsPointNullable returns if the range is a point.
 // TODO: unify the parameter type with IsPointNullable and IsPoint
-func (ran *Range) IsPointNullable(stmtCtx *stmtctx.StatementContext) bool {
-	return ran.isPoint(stmtCtx, true)
+func (ran *Range) IsPointNullable(sctx sessionctx.Context) bool {
+	return ran.isPoint(sctx.GetSessionVars().StmtCtx, true)
 }
 
 // IsFullRange check if the range is full scan range
diff --git a/util/ranger/types_test.go b/util/ranger/types_test.go
index 1870f8da01ff6..d7e664dd323d8 100644
--- a/util/ranger/types_test.go
+++ b/util/ranger/types_test.go
@@ -25,7 +25,6 @@ import (
 )
 
 func TestRange(t *testing.T) {
-	t.Parallel()
 	simpleTests := []struct {
 		ran ranger.Range
 		str string
@@ -130,7 +129,6 @@ func TestRange(t *testing.T) {
 }
 
 func TestIsFullRange(t *testing.T) {
-	t.Parallel()
 	nullDatum := types.MinNotNullDatum()
 	nullDatum.SetNull()
 	isFullRangeTests := []struct {
diff --git a/util/resourcegrouptag/resource_group_tag_test.go b/util/resourcegrouptag/resource_group_tag_test.go
index 5cf65d52ad411..98d864829b189 100644
--- a/util/resourcegrouptag/resource_group_tag_test.go
+++ b/util/resourcegrouptag/resource_group_tag_test.go
@@ -29,8 +29,6 @@ import (
 )
 
 func TestResourceGroupTagEncoding(t *testing.T) {
-	t.Parallel()
-
 	sqlDigest := parser.NewDigest(nil)
 	tag := EncodeResourceGroupTag(sqlDigest, nil, tipb.ResourceGroupTagLabel_ResourceGroupTagLabelUnknown)
 	require.Len(t, tag, 2)
@@ -62,8 +60,6 @@ func TestResourceGroupTagEncoding(t *testing.T) {
 }
 
 func TestResourceGroupTagEncodingPB(t *testing.T) {
-	t.Parallel()
-
 	digest1 := genDigest("abc")
 	digest2 := genDigest("abcdefg")
 	// Test for protobuf
diff --git a/util/rowDecoder/decoder_test.go b/util/rowDecoder/decoder_test.go
index 26abf03eb6e95..8d1081f528559 100644
--- a/util/rowDecoder/decoder_test.go
+++ b/util/rowDecoder/decoder_test.go
@@ -36,7 +36,6 @@ import (
 )
 
 func TestRowDecoder(t *testing.T) {
-	t.Parallel()
 	c1 := &model.ColumnInfo{ID: 1, Name: model.NewCIStr("c1"), State: model.StatePublic, Offset: 0, FieldType: *types.NewFieldType(mysql.TypeLonglong)}
 	c2 := &model.ColumnInfo{ID: 2, Name: model.NewCIStr("c2"), State: model.StatePublic, Offset: 1, FieldType: *types.NewFieldType(mysql.TypeVarchar)}
 	c3 := &model.ColumnInfo{ID: 3, Name: model.NewCIStr("c3"), State: model.StatePublic, Offset: 2, FieldType: *types.NewFieldType(mysql.TypeNewDecimal)}
@@ -152,7 +151,6 @@ func TestRowDecoder(t *testing.T) {
 }
 
 func TestClusterIndexRowDecoder(t *testing.T) {
-	t.Parallel()
 	c1 := &model.ColumnInfo{ID: 1, Name: model.NewCIStr("c1"), State: model.StatePublic, Offset: 0, FieldType: *types.NewFieldType(mysql.TypeLonglong)}
 	c2 := &model.ColumnInfo{ID: 2, Name: model.NewCIStr("c2"), State: model.StatePublic, Offset: 1, FieldType: *types.NewFieldType(mysql.TypeVarchar)}
 	c3 := &model.ColumnInfo{ID: 3, Name: model.NewCIStr("c3"), State: model.StatePublic, Offset: 2, FieldType: *types.NewFieldType(mysql.TypeNewDecimal)}
diff --git a/util/rowcodec/rowcodec_test.go b/util/rowcodec/rowcodec_test.go
index 58bc81b5b86f6..1ea59e0eea564 100644
--- a/util/rowcodec/rowcodec_test.go
+++ b/util/rowcodec/rowcodec_test.go
@@ -43,8 +43,6 @@ type testData struct {
 }
 
 func TestEncodeLargeSmallReuseBug(t *testing.T) {
-	t.Parallel()
-
 	// reuse one rowcodec.Encoder.
 	var encoder rowcodec.Encoder
 	colFt := types.NewFieldType(mysql.TypeString)
@@ -83,8 +81,6 @@ func TestEncodeLargeSmallReuseBug(t *testing.T) {
 }
 
 func TestDecodeRowWithHandle(t *testing.T) {
-	t.Parallel()
-
 	handleID := int64(-1)
 	handleValue := int64(10000)
 
@@ -223,8 +219,6 @@ func TestDecodeRowWithHandle(t *testing.T) {
 }
 
 func TestEncodeKindNullDatum(t *testing.T) {
-	t.Parallel()
-
 	var encoder rowcodec.Encoder
 	sc := new(stmtctx.StatementContext)
 	sc.TimeZone = time.UTC
@@ -251,8 +245,6 @@ func TestEncodeKindNullDatum(t *testing.T) {
 }
 
 func TestDecodeDecimalFspNotMatch(t *testing.T) {
-	t.Parallel()
-
 	var encoder rowcodec.Encoder
 	sc := new(stmtctx.StatementContext)
 	sc.TimeZone = time.UTC
@@ -287,8 +279,6 @@ func TestDecodeDecimalFspNotMatch(t *testing.T) {
 }
 
 func TestTypesNewRowCodec(t *testing.T) {
-	t.Parallel()
-
 	getJSONDatum := func(value string) types.Datum {
 		j, err := json.ParseBinaryFromString(value)
 		require.NoError(t, err)
@@ -563,8 +553,6 @@ func TestTypesNewRowCodec(t *testing.T) {
 }
 
 func TestNilAndDefault(t *testing.T) {
-	t.Parallel()
-
 	td := []testData{
 		{
 			1,
@@ -696,8 +684,6 @@ func TestNilAndDefault(t *testing.T) {
 }
 
 func TestVarintCompatibility(t *testing.T) {
-	t.Parallel()
-
 	td := []testData{
 		{
 			1,
@@ -755,8 +741,6 @@ func TestVarintCompatibility(t *testing.T) {
 }
 
 func TestCodecUtil(t *testing.T) {
-	t.Parallel()
-
 	colIDs := []int64{1, 2, 3, 4}
 	tps := make([]*types.FieldType, 4)
 	for i := 0; i < 3; i++ {
@@ -807,8 +791,6 @@ func TestCodecUtil(t *testing.T) {
 }
 
 func TestOldRowCodec(t *testing.T) {
-	t.Parallel()
-
 	colIDs := []int64{1, 2, 3, 4}
 	tps := make([]*types.FieldType, 4)
 	for i := 0; i < 3; i++ {
@@ -844,8 +826,6 @@ func TestOldRowCodec(t *testing.T) {
 }
 
 func Test65535Bug(t *testing.T) {
-	t.Parallel()
-
 	colIds := []int64{1}
 	tps := make([]*types.FieldType, 1)
 	tps[0] = types.NewFieldType(mysql.TypeString)
diff --git a/util/selection/selection_test.go b/util/selection/selection_test.go
index e8eb5ffed0336..310502f8886e9 100644
--- a/util/selection/selection_test.go
+++ b/util/selection/selection_test.go
@@ -50,14 +50,12 @@ func init() {
 }
 
 func TestSelection(t *testing.T) {
-	t.Parallel()
 	data := testSlice{1, 2, 3, 4, 5}
 	index := Select(data, 3)
 	require.Equal(t, 3, data[index])
 }
 
 func TestSelectionWithDuplicate(t *testing.T) {
-	t.Parallel()
 	data := testSlice{1, 2, 3, 3, 5}
 	index := Select(data, 3)
 	require.Equal(t, 3, data[index])
@@ -66,7 +64,6 @@ func TestSelectionWithDuplicate(t *testing.T) {
 }
 
 func TestSelectionWithRandomCase(t *testing.T) {
-	t.Parallel()
 	data := randomTestCase(1000000)
 	index := Select(data, 500000)
 	actual := data[index]
@@ -76,7 +73,6 @@ func TestSelectionWithRandomCase(t *testing.T) {
 }
 
 func TestSelectionWithSerialCase(t *testing.T) {
-	t.Parallel()
 	data := serialTestCase(1000000)
 	sort.Sort(sort.Reverse(data))
 	index := Select(data, 500000)
diff --git a/util/sem/sem_test.go b/util/sem/sem_test.go
index da3022830e4e3..ff11c3fd47eb9 100644
--- a/util/sem/sem_test.go
+++ b/util/sem/sem_test.go
@@ -24,7 +24,6 @@ import (
 )
 
 func TestInvisibleSchema(t *testing.T) {
-	t.Parallel()
 	assert := assert.New(t)
 
 	assert.True(IsInvisibleSchema(metricsSchema))
@@ -35,7 +34,6 @@ func TestInvisibleSchema(t *testing.T) {
 }
 
 func TestIsInvisibleTable(t *testing.T) {
-	t.Parallel()
 	assert := assert.New(t)
 
 	mysqlTbls := []string{exprPushdownBlacklist, gcDeleteRange, gcDeleteRangeDone, optRuleBlacklist, tidb, globalVariables}
@@ -61,7 +59,6 @@ func TestIsInvisibleTable(t *testing.T) {
 }
 
 func TestIsRestrictedPrivilege(t *testing.T) {
-	t.Parallel()
 	assert := assert.New(t)
 
 	assert.True(IsRestrictedPrivilege("RESTRICTED_TABLES_ADMIN"))
@@ -72,7 +69,6 @@ func TestIsRestrictedPrivilege(t *testing.T) {
 }
 
 func TestIsInvisibleStatusVar(t *testing.T) {
-	t.Parallel()
 	assert := assert.New(t)
 
 	assert.True(IsInvisibleStatusVar(tidbGCLeaderDesc))
@@ -82,7 +78,6 @@ func TestIsInvisibleStatusVar(t *testing.T) {
 }
 
 func TestIsInvisibleSysVar(t *testing.T) {
-	t.Parallel()
 	assert := assert.New(t)
 
 	assert.False(IsInvisibleSysVar(variable.Hostname))                   // changes the value to default, but is not invisible
diff --git a/util/set/float64_set_test.go b/util/set/float64_set_test.go
index 062f3ad918568..7fe1cd4389681 100644
--- a/util/set/float64_set_test.go
+++ b/util/set/float64_set_test.go
@@ -21,7 +21,6 @@ import (
 )
 
 func TestFloat64Set(t *testing.T) {
-	t.Parallel()
 	assert := assert.New(t)
 
 	set := NewFloat64Set()
diff --git a/util/set/int_set_test.go b/util/set/int_set_test.go
index d4cbcd8a6006e..cb7779a782f50 100644
--- a/util/set/int_set_test.go
+++ b/util/set/int_set_test.go
@@ -21,7 +21,6 @@ import (
 )
 
 func TestIntSet(t *testing.T) {
-	t.Parallel()
 	assert := assert.New(t)
 
 	set := NewIntSet()
@@ -44,7 +43,6 @@ func TestIntSet(t *testing.T) {
 }
 
 func TestInt64Set(t *testing.T) {
-	t.Parallel()
 	assert := assert.New(t)
 
 	set := NewInt64Set()
diff --git a/util/set/string_set_test.go b/util/set/string_set_test.go
index 4f16f834020c8..5d076be353207 100644
--- a/util/set/string_set_test.go
+++ b/util/set/string_set_test.go
@@ -22,7 +22,6 @@ import (
 )
 
 func TestStringSet(t *testing.T) {
-	t.Parallel()
 	assert := assert.New(t)
 
 	set := NewStringSet()
diff --git a/util/slice/slice_test.go b/util/slice/slice_test.go
index 318309f46d3d1..5a9b9ec17100f 100644
--- a/util/slice/slice_test.go
+++ b/util/slice/slice_test.go
@@ -36,7 +36,6 @@ func TestSlice(t *testing.T) {
 
 	for _, test := range tests {
 		t.Run(fmt.Sprint(test.a), func(t *testing.T) {
-			t.Parallel()
 			even := func(i int) bool { return test.a[i]%2 == 0 }
 			require.Equal(t, test.anyOf, AnyOf(test.a, even))
 			require.Equal(t, test.noneOf, NoneOf(test.a, even))
diff --git a/util/sqlexec/utils_test.go b/util/sqlexec/utils_test.go
index 7cc2b76d4c38e..0dc9abe826606 100644
--- a/util/sqlexec/utils_test.go
+++ b/util/sqlexec/utils_test.go
@@ -24,7 +24,6 @@ import (
 )
 
 func TestReserveBuffer(t *testing.T) {
-	t.Parallel()
 	res0 := reserveBuffer(nil, 0)
 	require.Len(t, res0, 0)
 
@@ -100,7 +99,6 @@ func TestEscapeBackslash(t *testing.T) {
 		// copy iterator variable into a new variable, see issue #27779
 		v := v
 		t.Run(v.name, func(t *testing.T) {
-			t.Parallel()
 			require.Equal(t, v.output, escapeBytesBackslash(nil, v.input))
 			require.Equal(t, v.output, escapeStringBackslash(nil, string(v.input)))
 		})
@@ -392,7 +390,6 @@ func TestEscapeSQL(t *testing.T) {
 		// copy iterator variable into a new variable, see issue #27779
 		v := v
 		t.Run(v.name, func(t *testing.T) {
-			t.Parallel()
 			r3 := new(strings.Builder)
 			r1, e1 := escapeSQL(v.input, v.params...)
 			r2, e2 := EscapeSQL(v.input, v.params...)
@@ -418,7 +415,6 @@ func TestEscapeSQL(t *testing.T) {
 }
 
 func TestMustUtils(t *testing.T) {
-	t.Parallel()
 	require.PanicsWithError(t, "missing arguments, need 1-th arg, but only got 0 args", func() {
 		MustEscapeSQL("%?")
 	})
diff --git a/util/stmtsummary/evicted_test.go b/util/stmtsummary/evicted_test.go
index 6e71cee668bca..9f7deeebaef67 100644
--- a/util/stmtsummary/evicted_test.go
+++ b/util/stmtsummary/evicted_test.go
@@ -58,7 +58,6 @@ func generateStmtSummaryByDigestKeyValue(schema string, beginTime int64, endTime
 
 // Test stmtSummaryByDigestMap.ToEvictedCountDatum
 func TestMapToEvictedCountDatum(t *testing.T) {
-	t.Parallel()
 	ssMap := newStmtSummaryByDigestMap()
 	ssMap.Clear()
 	now := time.Now().Unix()
@@ -143,7 +142,6 @@ func TestMapToEvictedCountDatum(t *testing.T) {
 
 // Test stmtSummaryByDigestEvicted
 func TestSimpleStmtSummaryByDigestEvicted(t *testing.T) {
-	t.Parallel()
 	ssbde := newStmtSummaryByDigestEvicted()
 	evictedKey, evictedValue := generateStmtSummaryByDigestKeyValue("a", 1, 2)
 
@@ -221,7 +219,6 @@ func TestSimpleStmtSummaryByDigestEvicted(t *testing.T) {
 
 // Test stmtSummaryByDigestEvictedElement.ToEvictedCountDatum
 func TestStmtSummaryByDigestEvictedElement(t *testing.T) {
-	t.Parallel()
 	record := newStmtSummaryByDigestEvictedElement(0, 1)
 	evictedKey, evictedValue := generateStmtSummaryByDigestKeyValue("alpha", 0, 1)
 	digestValue := evictedValue.history.Back().Value.(*stmtSummaryByDigestElement)
@@ -250,7 +247,6 @@ func TestStmtSummaryByDigestEvictedElement(t *testing.T) {
 // test stmtSummaryByDigestEvicted.addEvicted
 // test stmtSummaryByDigestEvicted.toEvictedCountDatum (single and multiple intervals)
 func TestEvictedCountDetailed(t *testing.T) {
-	t.Parallel()
 	ssMap := newStmtSummaryByDigestMap()
 	ssMap.Clear()
 	err := ssMap.SetRefreshInterval("60", false)
@@ -314,7 +310,6 @@ func TestEvictedCountDetailed(t *testing.T) {
 }
 
 func TestNewStmtSummaryByDigestEvictedElement(t *testing.T) {
-	t.Parallel()
 	now := time.Now().Unix()
 	end := now + 60
 	stmtEvictedElement := newStmtSummaryByDigestEvictedElement(now, end)
@@ -324,14 +319,12 @@ func TestNewStmtSummaryByDigestEvictedElement(t *testing.T) {
 }
 
 func TestStmtSummaryByDigestEvicted(t *testing.T) {
-	t.Parallel()
 	stmtEvicted := newStmtSummaryByDigestEvicted()
 	require.Equal(t, 0, stmtEvicted.history.Len())
 }
 
 // test addInfo function
 func TestAddInfo(t *testing.T) {
-	t.Parallel()
 	now := time.Now().Unix()
 	addTo := stmtSummaryByDigestElement{
 		// user
diff --git a/util/stmtsummary/statement_summary_test.go b/util/stmtsummary/statement_summary_test.go
index 000a7e0a9c087..2bcf4a82725a8 100644
--- a/util/stmtsummary/statement_summary_test.go
+++ b/util/stmtsummary/statement_summary_test.go
@@ -44,7 +44,6 @@ func fakePlanDigestGenerator() string {
 }
 
 func TestSetUp(t *testing.T) {
-	t.Parallel()
 	ssMap := newStmtSummaryByDigestMap()
 	err := ssMap.SetEnabled("1", false)
 	require.NoError(t, err)
@@ -60,7 +59,6 @@ const (
 
 // Test stmtSummaryByDigest.AddStatement.
 func TestAddStatement(t *testing.T) {
-	t.Parallel()
 	ssMap := newStmtSummaryByDigestMap()
 	now := time.Now().Unix()
 	ssMap.beginTimeForCurInterval = now + 60
@@ -751,7 +749,6 @@ func newStmtSummaryReaderForTest(ssMap *stmtSummaryByDigestMap) *stmtSummaryRead
 
 // Test stmtSummaryByDigest.ToDatum.
 func TestToDatum(t *testing.T) {
-	t.Parallel()
 	ssMap := newStmtSummaryByDigestMap()
 	now := time.Now().Unix()
 	// to disable expiration
@@ -849,7 +846,6 @@ func TestToDatum(t *testing.T) {
 
 // Test AddStatement and ToDatum parallel.
 func TestAddStatementParallel(t *testing.T) {
-	t.Parallel()
 	ssMap := newStmtSummaryByDigestMap()
 	now := time.Now().Unix()
 	// to disable expiration
@@ -887,7 +883,6 @@ func TestAddStatementParallel(t *testing.T) {
 
 // Test max number of statement count.
 func TestMaxStmtCount(t *testing.T) {
-	t.Parallel()
 	ssMap := newStmtSummaryByDigestMap()
 	now := time.Now().Unix()
 	// to disable expiration
@@ -947,7 +942,6 @@ func TestMaxStmtCount(t *testing.T) {
 
 // Test max length of normalized and sample SQL.
 func TestMaxSQLLength(t *testing.T) {
-	t.Parallel()
 	ssMap := newStmtSummaryByDigestMap()
 	now := time.Now().Unix()
 	// to disable expiration
@@ -991,7 +985,6 @@ func TestMaxSQLLength(t *testing.T) {
 
 // Test AddStatement and SetMaxStmtCount parallel.
 func TestSetMaxStmtCountParallel(t *testing.T) {
-	t.Parallel()
 	ssMap := newStmtSummaryByDigestMap()
 	now := time.Now().Unix()
 	// to disable expiration
@@ -1039,7 +1032,6 @@ func TestSetMaxStmtCountParallel(t *testing.T) {
 
 // Test setting EnableStmtSummary to 0.
 func TestDisableStmtSummary(t *testing.T) {
-	t.Parallel()
 	ssMap := newStmtSummaryByDigestMap()
 	now := time.Now().Unix()
 
@@ -1098,7 +1090,6 @@ func TestDisableStmtSummary(t *testing.T) {
 
 // Test disable and enable statement summary concurrently with adding statements.
 func TestEnableSummaryParallel(t *testing.T) {
-	t.Parallel()
 	ssMap := newStmtSummaryByDigestMap()
 
 	threads := 8
@@ -1136,7 +1127,6 @@ func TestEnableSummaryParallel(t *testing.T) {
 
 // Test GetMoreThanCntBindableStmt.
 func TestGetMoreThanCntBindableStmt(t *testing.T) {
-	t.Parallel()
 	ssMap := newStmtSummaryByDigestMap()
 
 	stmtExecInfo1 := generateAnyExecInfo()
@@ -1161,7 +1151,6 @@ func TestGetMoreThanCntBindableStmt(t *testing.T) {
 
 // Test `formatBackoffTypes`.
 func TestFormatBackoffTypes(t *testing.T) {
-	t.Parallel()
 	backoffMap := make(map[string]int)
 	require.Nil(t, formatBackoffTypes(backoffMap))
 	bo1 := "pdrpc"
@@ -1175,7 +1164,6 @@ func TestFormatBackoffTypes(t *testing.T) {
 
 // Test refreshing current statement summary periodically.
 func TestRefreshCurrentSummary(t *testing.T) {
-	t.Parallel()
 	ssMap := newStmtSummaryByDigestMap()
 	now := time.Now().Unix()
 
@@ -1215,7 +1203,6 @@ func TestRefreshCurrentSummary(t *testing.T) {
 
 // Test expiring statement summary to history.
 func TestSummaryHistory(t *testing.T) {
-	t.Parallel()
 	ssMap := newStmtSummaryByDigestMap()
 	now := time.Now().Unix()
 	err := ssMap.SetRefreshInterval("10", false)
@@ -1295,7 +1282,6 @@ func TestSummaryHistory(t *testing.T) {
 
 // Test summary when PrevSQL is not empty.
 func TestPrevSQL(t *testing.T) {
-	t.Parallel()
 	ssMap := newStmtSummaryByDigestMap()
 	now := time.Now().Unix()
 	// to disable expiration
@@ -1331,7 +1317,6 @@ func TestPrevSQL(t *testing.T) {
 }
 
 func TestEndTime(t *testing.T) {
-	t.Parallel()
 	ssMap := newStmtSummaryByDigestMap()
 	now := time.Now().Unix()
 	ssMap.beginTimeForCurInterval = now - 100
@@ -1379,7 +1364,6 @@ func TestEndTime(t *testing.T) {
 }
 
 func TestPointGet(t *testing.T) {
-	t.Parallel()
 	ssMap := newStmtSummaryByDigestMap()
 	now := time.Now().Unix()
 	ssMap.beginTimeForCurInterval = now - 100
@@ -1405,7 +1389,6 @@ func TestPointGet(t *testing.T) {
 }
 
 func TestAccessPrivilege(t *testing.T) {
-	t.Parallel()
 	ssMap := newStmtSummaryByDigestMap()
 
 	loops := 32
diff --git a/util/stmtsummary/variables_test.go b/util/stmtsummary/variables_test.go
index 2927f4bd96fc6..72ed04682b6eb 100644
--- a/util/stmtsummary/variables_test.go
+++ b/util/stmtsummary/variables_test.go
@@ -22,7 +22,6 @@ import (
 )
 
 func TestSetInVariable(t *testing.T) {
-	t.Parallel()
 	sv := newSysVars()
 	st := sv.getVariable(typeMaxStmtCount)
 	require.Equal(t, int64(config.GetGlobalConfig().StmtSummary.MaxStmtCount), st)
@@ -58,7 +57,6 @@ func TestSetInVariable(t *testing.T) {
 }
 
 func TestSetBoolVariable(t *testing.T) {
-	t.Parallel()
 	sv := newSysVars()
 	en := sv.getVariable(typeEnable)
 	require.Equal(t, config.GetGlobalConfig().StmtSummary.Enable, en > 0)
@@ -98,7 +96,6 @@ func TestSetBoolVariable(t *testing.T) {
 }
 
 func TestMinValue(t *testing.T) {
-	t.Parallel()
 	sv := newSysVars()
 	err := sv.setVariable(typeMaxStmtCount, "0", false)
 	require.NoError(t, err)
diff --git a/util/stringutil/string_util_test.go b/util/stringutil/string_util_test.go
index f9451a4a9918a..a5a666a8f848e 100644
--- a/util/stringutil/string_util_test.go
+++ b/util/stringutil/string_util_test.go
@@ -21,7 +21,6 @@ import (
 )
 
 func TestUnquote(t *testing.T) {
-	t.Parallel()
 	table := []struct {
 		str    string
 		expect string
@@ -67,7 +66,6 @@ func TestUnquote(t *testing.T) {
 }
 
 func TestPatternMatch(t *testing.T) {
-	t.Parallel()
 	tbl := []struct {
 		pattern string
 		input   string
@@ -111,7 +109,6 @@ func TestPatternMatch(t *testing.T) {
 }
 
 func TestCompileLike2Regexp(t *testing.T) {
-	t.Parallel()
 	tbl := []struct {
 		pattern string
 		regexp  string
@@ -139,7 +136,6 @@ func TestCompileLike2Regexp(t *testing.T) {
 }
 
 func TestIsExactMatch(t *testing.T) {
-	t.Parallel()
 	tbl := []struct {
 		pattern    string
 		escape     byte
@@ -167,7 +163,6 @@ func TestIsExactMatch(t *testing.T) {
 }
 
 func TestBuildStringFromLabels(t *testing.T) {
-	t.Parallel()
 	tbl := []struct {
 		name     string
 		labels   map[string]string
diff --git a/util/sys/linux/sys_test.go b/util/sys/linux/sys_test.go
index 6522df0d2e08d..7ce52ca8f123d 100644
--- a/util/sys/linux/sys_test.go
+++ b/util/sys/linux/sys_test.go
@@ -21,8 +21,6 @@ import (
 )
 
 func TestGetOSVersion(t *testing.T) {
-	t.Parallel()
-
 	osRelease, err := OSVersion()
 	require.NoError(t, err)
 	require.NotEmpty(t, osRelease)
diff --git a/util/sys/storage/sys_test.go b/util/sys/storage/sys_test.go
index fd73c81c07dcf..0f8c39ce3c50c 100644
--- a/util/sys/storage/sys_test.go
+++ b/util/sys/storage/sys_test.go
@@ -22,7 +22,6 @@ import (
 )
 
 func TestGetTargetDirectoryCapacity(t *testing.T) {
-	t.Parallel()
 	r, err := storage.GetTargetDirectoryCapacity(".")
 	require.NoError(t, err)
 	require.GreaterOrEqual(t, r, uint64(1), "couldn't get capacity")
diff --git a/util/systimemon/systime_mon_test.go b/util/systimemon/systime_mon_test.go
index 3950db9a9c52e..f05098b63db7e 100644
--- a/util/systimemon/systime_mon_test.go
+++ b/util/systimemon/systime_mon_test.go
@@ -23,8 +23,6 @@ import (
 )
 
 func TestSystimeMonitor(t *testing.T) {
-	t.Parallel()
-
 	errTriggered := atomic.NewBool(false)
 	nowTriggered := atomic.NewBool(false)
 	go StartMonitor(
diff --git a/util/testkit/testkit.go b/util/testkit/testkit.go
index 4b1882849b1e8..e1f0542797c14 100644
--- a/util/testkit/testkit.go
+++ b/util/testkit/testkit.go
@@ -260,7 +260,7 @@ func (tk *TestKit) HasPlan(sql string, plan string, args ...interface{}) bool {
 	return false
 }
 
-func containGloabl(rs *Result) bool {
+func containGlobal(rs *Result) bool {
 	partitionNameCol := 2
 	for i := range rs.rows {
 		if strings.Contains(rs.rows[i][partitionNameCol], "global") {
@@ -272,13 +272,13 @@ func containGloabl(rs *Result) bool {
 
 // MustNoGlobalStats checks if there is no global stats.
 func (tk *TestKit) MustNoGlobalStats(table string) bool {
-	if containGloabl(tk.MustQuery("show stats_meta where table_name like '" + table + "'")) {
+	if containGlobal(tk.MustQuery("show stats_meta where table_name like '" + table + "'")) {
 		return false
 	}
-	if containGloabl(tk.MustQuery("show stats_buckets where table_name like '" + table + "'")) {
+	if containGlobal(tk.MustQuery("show stats_buckets where table_name like '" + table + "'")) {
 		return false
 	}
-	if containGloabl(tk.MustQuery("show stats_histograms where table_name like '" + table + "'")) {
+	if containGlobal(tk.MustQuery("show stats_histograms where table_name like '" + table + "'")) {
 		return false
 	}
 	return true
diff --git a/util/texttree/texttree_test.go b/util/texttree/texttree_test.go
index 6a3646c6596eb..5143cac90e2ed 100644
--- a/util/texttree/texttree_test.go
+++ b/util/texttree/texttree_test.go
@@ -22,7 +22,6 @@ import (
 )
 
 func TestPrettyIdentifier(t *testing.T) {
-	t.Parallel()
 	require.Equal(t, "test", texttree.PrettyIdentifier("test", "", false))
 	require.Equal(t, "  ├ ─test", texttree.PrettyIdentifier("test", "  │  ", false))
 	require.Equal(t, "\t\t├\t─test", texttree.PrettyIdentifier("test", "\t\t│\t\t", false))
@@ -31,7 +30,6 @@ func TestPrettyIdentifier(t *testing.T) {
 }
 
 func TestIndent4Child(t *testing.T) {
-	t.Parallel()
 	require.Equal(t, "    │ ", texttree.Indent4Child("    ", false))
 	require.Equal(t, "    │ ", texttree.Indent4Child("    ", true))
 	require.Equal(t, "     │ ", texttree.Indent4Child("   │ ", true))
diff --git a/util/timeutil/time_test.go b/util/timeutil/time_test.go
index 036dd3cfd5333..7795092c8013e 100644
--- a/util/timeutil/time_test.go
+++ b/util/timeutil/time_test.go
@@ -28,8 +28,6 @@ import (
 )
 
 func TestGetTZNameFromFileName(t *testing.T) {
-	t.Parallel()
-
 	tz, err := inferTZNameFromFileName("/usr/share/zoneinfo/Asia/Shanghai")
 
 	require.NoError(t, err)
@@ -42,8 +40,6 @@ func TestGetTZNameFromFileName(t *testing.T) {
 }
 
 func TestLocal(t *testing.T) {
-	t.Parallel()
-
 	os.Setenv("TZ", "Asia/Shanghai")
 	systemTZ.Store(InferSystemTZ())
 	loc := SystemLocation()
@@ -65,8 +61,6 @@ func TestLocal(t *testing.T) {
 }
 
 func TestInferOneStepLinkForPath(t *testing.T) {
-	t.Parallel()
-
 	os.Remove(filepath.Join(os.TempDir(), "testlink1"))
 	os.Remove(filepath.Join(os.TempDir(), "testlink2"))
 	os.Remove(filepath.Join(os.TempDir(), "testlink3"))
diff --git a/util/topsql/reporter/datasink.go b/util/topsql/reporter/datasink.go
new file mode 100644
index 0000000000000..c4206c71dc440
--- /dev/null
+++ b/util/topsql/reporter/datasink.go
@@ -0,0 +1,36 @@
+// Copyright 2021 PingCAP, Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package reporter
+
+import "time"
+
+// DataSink collects and sends data to a target.
+type DataSink interface {
+	// TrySend pushes a report data into the sink, which will later be sent to a target by the sink. A deadline can be
+	// specified to control how late it should be sent. If the sink is kept full and cannot schedule a send within
+	// the specified deadline, or the sink is closed, an error will be returned.
+	TrySend(data ReportData, deadline time.Time) error
+
+	// IsPaused indicates that the DataSink is not expecting to receive records for now
+	// and may resume in the future.
+	IsPaused() bool
+
+	// IsDown indicates that the DataSink has been down and can be cleared.
+	// Note that: once a DataSink is down, it cannot go back to be up.
+	IsDown() bool
+
+	// Close cleans up resources owned by this DataSink
+	Close()
+}
diff --git a/util/topsql/reporter/reporter.go b/util/topsql/reporter/reporter.go
index 113cb5ce29bc4..39e3be5eae8e4 100644
--- a/util/topsql/reporter/reporter.go
+++ b/util/topsql/reporter/reporter.go
@@ -23,7 +23,6 @@ import (
 	"time"
 
 	"github.com/pingcap/failpoint"
-	"github.com/pingcap/tidb/config"
 	"github.com/pingcap/tidb/metrics"
 	"github.com/pingcap/tidb/sessionctx/variable"
 	"github.com/pingcap/tidb/util"
@@ -118,9 +117,9 @@ type planBinaryDecodeFunc func(string) (string, error)
 // RemoteTopSQLReporter implements a TopSQL reporter that sends data to a remote agent
 // This should be called periodically to collect TopSQL resource usage metrics
 type RemoteTopSQLReporter struct {
-	ctx    context.Context
-	cancel context.CancelFunc
-	client ReportClient
+	ctx      context.Context
+	cancel   context.CancelFunc
+	dataSink DataSink
 
 	// normalizedSQLMap is an map, whose keys are SQL digest strings and values are SQLMeta.
 	normalizedSQLMap atomic.Value // sync.Map
@@ -145,12 +144,12 @@ type SQLMeta struct {
 //
 // planBinaryDecoder is a decoding function which will be called asynchronously to decode the plan binary to string
 // MaxStatementsNum is the maximum SQL and plan number, which will restrict the memory usage of the internal LFU cache
-func NewRemoteTopSQLReporter(client ReportClient) *RemoteTopSQLReporter {
+func NewRemoteTopSQLReporter(dataSink DataSink) *RemoteTopSQLReporter {
 	ctx, cancel := context.WithCancel(context.Background())
 	tsr := &RemoteTopSQLReporter{
 		ctx:                     ctx,
 		cancel:                  cancel,
-		client:                  client,
+		dataSink:                dataSink,
 		collectCPUDataChan:      make(chan cpuData, 1),
 		reportCollectedDataChan: make(chan collectedData, 1),
 	}
@@ -238,7 +237,7 @@ func (tsr *RemoteTopSQLReporter) Collect(timestamp uint64, records []tracecpu.SQ
 // Close uses to close and release the reporter resource.
 func (tsr *RemoteTopSQLReporter) Close() {
 	tsr.cancel()
-	tsr.client.Close()
+	tsr.dataSink.Close()
 }
 
 func addEvictedCPUTime(collectTarget map[string]*dataPoints, timestamp uint64, totalCPUTimeMs uint32) {
@@ -450,15 +449,15 @@ type collectedData struct {
 	normalizedPlanMap *sync.Map
 }
 
-// reportData contains data that reporter sends to the agent
-type reportData struct {
+// ReportData contains data that reporter sends to the agent
+type ReportData struct {
 	// collectedData contains the topN collected records and the `others` record which aggregation all records that is out of Top N.
 	collectedData     []*dataPoints
 	normalizedSQLMap  *sync.Map
 	normalizedPlanMap *sync.Map
 }
 
-func (d *reportData) hasData() bool {
+func (d *ReportData) hasData() bool {
 	if len(d.collectedData) > 0 {
 		return true
 	}
@@ -496,9 +495,9 @@ func (tsr *RemoteTopSQLReporter) reportWorker() {
 	}
 }
 
-// getReportData gets reportData from the collectedData.
+// getReportData gets ReportData from the collectedData.
 // This function will calculate the topN collected records and the `others` record which aggregation all records that is out of Top N.
-func (tsr *RemoteTopSQLReporter) getReportData(collected collectedData) reportData {
+func (tsr *RemoteTopSQLReporter) getReportData(collected collectedData) ReportData {
 	// Fetch TopN dataPoints.
 	others := collected.records[keyOthers]
 	delete(collected.records, keyOthers)
@@ -524,21 +523,20 @@ func (tsr *RemoteTopSQLReporter) getReportData(collected collectedData) reportDa
 		records = append(records, others)
 	}
 
-	return reportData{
+	return ReportData{
 		collectedData:     records,
 		normalizedSQLMap:  collected.normalizedSQLMap,
 		normalizedPlanMap: collected.normalizedPlanMap,
 	}
 }
 
-func (tsr *RemoteTopSQLReporter) doReport(data reportData) {
+func (tsr *RemoteTopSQLReporter) doReport(data ReportData) {
 	defer util.Recover("top-sql", "doReport", nil, false)
 
 	if !data.hasData() {
 		return
 	}
 
-	agentAddr := config.GetGlobalConfig().TopSQL.ReceiverAddress
 	timeout := reportTimeout
 	failpoint.Inject("resetTimeoutForTest", func(val failpoint.Value) {
 		if val.(bool) {
@@ -548,14 +546,8 @@ func (tsr *RemoteTopSQLReporter) doReport(data reportData) {
 			}
 		}
 	})
-	ctx, cancel := context.WithTimeout(tsr.ctx, timeout)
-	start := time.Now()
-	err := tsr.client.Send(ctx, agentAddr, data)
-	if err != nil {
-		logutil.BgLogger().Warn("[top-sql] client failed to send data", zap.Error(err))
-		reportAllDurationFailedHistogram.Observe(time.Since(start).Seconds())
-	} else {
-		reportAllDurationSuccHistogram.Observe(time.Since(start).Seconds())
+	deadline := time.Now().Add(timeout)
+	if err := tsr.dataSink.TrySend(data, deadline); err != nil {
+		logutil.BgLogger().Warn("[top-sql] failed to send data to datasink", zap.Error(err))
 	}
-	cancel()
 }
diff --git a/util/topsql/reporter/reporter_test.go b/util/topsql/reporter/reporter_test.go
index ab146930b85a7..33d048fcf1d86 100644
--- a/util/topsql/reporter/reporter_test.go
+++ b/util/topsql/reporter/reporter_test.go
@@ -72,7 +72,7 @@ func setupRemoteTopSQLReporter(maxStatementsNum, interval int, addr string) *Rem
 		conf.TopSQL.ReceiverAddress = addr
 	})
 
-	rc := NewGRPCReportClient(mockPlanBinaryDecoderFunc)
+	rc := NewSingleTargetDataSink(mockPlanBinaryDecoderFunc)
 	ts := NewRemoteTopSQLReporter(rc)
 	return ts
 }
diff --git a/util/topsql/reporter/client.go b/util/topsql/reporter/single_target.go
similarity index 55%
rename from util/topsql/reporter/client.go
rename to util/topsql/reporter/single_target.go
index 994189250e52b..5ed12c11853d8 100644
--- a/util/topsql/reporter/client.go
+++ b/util/topsql/reporter/single_target.go
@@ -16,10 +16,12 @@ package reporter
 
 import (
 	"context"
+	"errors"
 	"math"
 	"sync"
 	"time"
 
+	"github.com/pingcap/tidb/config"
 	"github.com/pingcap/tidb/util/logutil"
 	"github.com/pingcap/tipb/go-tipb"
 	"go.uber.org/zap"
@@ -27,36 +29,126 @@ import (
 	"google.golang.org/grpc/backoff"
 )
 
-// ReportClient send data to the target server.
-type ReportClient interface {
-	Send(ctx context.Context, addr string, data reportData) error
-	Close()
-}
+// SingleTargetDataSink reports data to grpc servers.
+type SingleTargetDataSink struct {
+	ctx    context.Context
+	cancel context.CancelFunc
 
-// GRPCReportClient reports data to grpc servers.
-type GRPCReportClient struct {
 	curRPCAddr string
 	conn       *grpc.ClientConn
+	sendTaskCh chan sendTask
+
 	// calling decodePlan this can take a while, so should not block critical paths
 	decodePlan planBinaryDecodeFunc
 }
 
-// NewGRPCReportClient returns a new GRPCReportClient
-func NewGRPCReportClient(decodePlan planBinaryDecodeFunc) *GRPCReportClient {
-	return &GRPCReportClient{
+// NewSingleTargetDataSink returns a new SingleTargetDataSink
+func NewSingleTargetDataSink(decodePlan planBinaryDecodeFunc) *SingleTargetDataSink {
+	ctx, cancel := context.WithCancel(context.Background())
+	dataSink := &SingleTargetDataSink{
+		ctx:    ctx,
+		cancel: cancel,
+
+		curRPCAddr: "",
+		conn:       nil,
+		sendTaskCh: make(chan sendTask, 1),
+
 		decodePlan: decodePlan,
 	}
+	go dataSink.recoverRun()
+	return dataSink
+}
+
+// recoverRun will run until SingleTargetDataSink is closed.
+func (ds *SingleTargetDataSink) recoverRun() {
+	for ds.run() {
+	}
+}
+
+func (ds *SingleTargetDataSink) run() (rerun bool) {
+	defer func() {
+		r := recover()
+		if r != nil {
+			logutil.BgLogger().Error("panic in SingleTargetDataSink, rerun",
+				zap.Reflect("r", r),
+				zap.Stack("stack trace"))
+			rerun = true
+		}
+	}()
+
+	for {
+		var task sendTask
+		select {
+		case <-ds.ctx.Done():
+			return false
+		case task = <-ds.sendTaskCh:
+		}
+
+		targetRPCAddr := config.GetGlobalConfig().TopSQL.ReceiverAddress
+		if targetRPCAddr == "" {
+			continue
+		}
+
+		ctx, cancel := context.WithDeadline(context.Background(), task.deadline)
+		start := time.Now()
+		err := ds.doSend(ctx, targetRPCAddr, task.data)
+		cancel()
+		if err != nil {
+			logutil.BgLogger().Warn("[top-sql] single target data sink failed to send data to receiver", zap.Error(err))
+			reportAllDurationFailedHistogram.Observe(time.Since(start).Seconds())
+		} else {
+			reportAllDurationSuccHistogram.Observe(time.Since(start).Seconds())
+		}
+	}
 }
 
-var _ ReportClient = &GRPCReportClient{}
+var _ DataSink = &SingleTargetDataSink{}
 
-// Send implements the ReportClient interface.
-// Currently the implementation will establish a new connection every time, which is suitable for a per-minute sending period
-func (r *GRPCReportClient) Send(ctx context.Context, targetRPCAddr string, data reportData) error {
-	if targetRPCAddr == "" {
+// TrySend implements the DataSink interface.
+// Currently the implementation will establish a new connection every time,
+// which is suitable for a per-minute sending period
+func (ds *SingleTargetDataSink) TrySend(data ReportData, deadline time.Time) error {
+	select {
+	case ds.sendTaskCh <- sendTask{data: data, deadline: deadline}:
 		return nil
+	case <-ds.ctx.Done():
+		return ds.ctx.Err()
+	default:
+		ignoreReportChannelFullCounter.Inc()
+		return errors.New("the channel of single target dataSink is full")
+	}
+}
+
+// IsPaused implements the DataSink interface.
+func (ds *SingleTargetDataSink) IsPaused() bool {
+	return len(config.GetGlobalConfig().TopSQL.ReceiverAddress) == 0
+}
+
+// IsDown implements the DataSink interface.
+func (ds *SingleTargetDataSink) IsDown() bool {
+	select {
+	case <-ds.ctx.Done():
+		return true
+	default:
+		return false
+	}
+}
+
+// Close uses to close grpc connection.
+func (ds *SingleTargetDataSink) Close() {
+	ds.cancel()
+	if ds.conn == nil {
+		return
+	}
+	err := ds.conn.Close()
+	if err != nil {
+		logutil.BgLogger().Warn("[top-sql] single target dataSink close connection failed", zap.Error(err))
 	}
-	err := r.tryEstablishConnection(ctx, targetRPCAddr)
+	ds.conn = nil
+}
+
+func (ds *SingleTargetDataSink) doSend(ctx context.Context, addr string, data ReportData) error {
+	err := ds.tryEstablishConnection(ctx, addr)
 	if err != nil {
 		return err
 	}
@@ -67,15 +159,15 @@ func (r *GRPCReportClient) Send(ctx context.Context, targetRPCAddr string, data
 
 	go func() {
 		defer wg.Done()
-		errCh <- r.sendBatchSQLMeta(ctx, data.normalizedSQLMap)
+		errCh <- ds.sendBatchSQLMeta(ctx, data.normalizedSQLMap)
 	}()
 	go func() {
 		defer wg.Done()
-		errCh <- r.sendBatchPlanMeta(ctx, data.normalizedPlanMap)
+		errCh <- ds.sendBatchPlanMeta(ctx, data.normalizedPlanMap)
 	}()
 	go func() {
 		defer wg.Done()
-		errCh <- r.sendBatchCPUTimeRecord(ctx, data.collectedData)
+		errCh <- ds.sendBatchCPUTimeRecord(ctx, data.collectedData)
 	}()
 	wg.Wait()
 	close(errCh)
@@ -87,25 +179,13 @@ func (r *GRPCReportClient) Send(ctx context.Context, targetRPCAddr string, data
 	return nil
 }
 
-// Close uses to close grpc connection.
-func (r *GRPCReportClient) Close() {
-	if r.conn == nil {
-		return
-	}
-	err := r.conn.Close()
-	if err != nil {
-		logutil.BgLogger().Warn("[top-sql] grpc client close connection failed", zap.Error(err))
-	}
-	r.conn = nil
-}
-
 // sendBatchCPUTimeRecord sends a batch of TopSQL records by stream.
-func (r *GRPCReportClient) sendBatchCPUTimeRecord(ctx context.Context, records []*dataPoints) error {
+func (ds *SingleTargetDataSink) sendBatchCPUTimeRecord(ctx context.Context, records []*dataPoints) error {
 	if len(records) == 0 {
 		return nil
 	}
 	start := time.Now()
-	client := tipb.NewTopSQLAgentClient(r.conn)
+	client := tipb.NewTopSQLAgentClient(ds.conn)
 	stream, err := client.ReportCPUTimeRecords(ctx)
 	if err != nil {
 		return err
@@ -133,9 +213,9 @@ func (r *GRPCReportClient) sendBatchCPUTimeRecord(ctx context.Context, records [
 }
 
 // sendBatchSQLMeta sends a batch of SQL metas by stream.
-func (r *GRPCReportClient) sendBatchSQLMeta(ctx context.Context, sqlMap *sync.Map) error {
+func (ds *SingleTargetDataSink) sendBatchSQLMeta(ctx context.Context, sqlMap *sync.Map) error {
 	start := time.Now()
-	client := tipb.NewTopSQLAgentClient(r.conn)
+	client := tipb.NewTopSQLAgentClient(ds.conn)
 	stream, err := client.ReportSQLMeta(ctx)
 	if err != nil {
 		return err
@@ -169,16 +249,16 @@ func (r *GRPCReportClient) sendBatchSQLMeta(ctx context.Context, sqlMap *sync.Ma
 }
 
 // sendBatchPlanMeta sends a batch of SQL metas by stream.
-func (r *GRPCReportClient) sendBatchPlanMeta(ctx context.Context, planMap *sync.Map) error {
+func (ds *SingleTargetDataSink) sendBatchPlanMeta(ctx context.Context, planMap *sync.Map) error {
 	start := time.Now()
-	client := tipb.NewTopSQLAgentClient(r.conn)
+	client := tipb.NewTopSQLAgentClient(ds.conn)
 	stream, err := client.ReportPlanMeta(ctx)
 	if err != nil {
 		return err
 	}
 	cnt := 0
 	planMap.Range(func(key, value interface{}) bool {
-		planDecoded, errDecode := r.decodePlan(value.(string))
+		planDecoded, errDecode := ds.decodePlan(value.(string))
 		if errDecode != nil {
 			logutil.BgLogger().Warn("[top-sql] decode plan failed", zap.Error(errDecode))
 			return true
@@ -208,26 +288,26 @@ func (r *GRPCReportClient) sendBatchPlanMeta(ctx context.Context, planMap *sync.
 }
 
 // tryEstablishConnection establishes the gRPC connection if connection is not established.
-func (r *GRPCReportClient) tryEstablishConnection(ctx context.Context, targetRPCAddr string) (err error) {
-	if r.curRPCAddr == targetRPCAddr && r.conn != nil {
+func (ds *SingleTargetDataSink) tryEstablishConnection(ctx context.Context, targetRPCAddr string) (err error) {
+	if ds.curRPCAddr == targetRPCAddr && ds.conn != nil {
 		// Address is not changed, skip.
 		return nil
 	}
 
-	if r.conn != nil {
-		err := r.conn.Close()
-		logutil.BgLogger().Warn("[top-sql] grpc client close connection failed", zap.Error(err))
+	if ds.conn != nil {
+		err := ds.conn.Close()
+		logutil.BgLogger().Warn("[top-sql] grpc dataSink close connection failed", zap.Error(err))
 	}
 
-	r.conn, err = r.dial(ctx, targetRPCAddr)
+	ds.conn, err = ds.dial(ctx, targetRPCAddr)
 	if err != nil {
 		return err
 	}
-	r.curRPCAddr = targetRPCAddr
+	ds.curRPCAddr = targetRPCAddr
 	return nil
 }
 
-func (r *GRPCReportClient) dial(ctx context.Context, targetRPCAddr string) (*grpc.ClientConn, error) {
+func (ds *SingleTargetDataSink) dial(ctx context.Context, targetRPCAddr string) (*grpc.ClientConn, error) {
 	dialCtx, cancel := context.WithTimeout(ctx, dialTimeout)
 	defer cancel()
 	return grpc.DialContext(
@@ -250,3 +330,8 @@ func (r *GRPCReportClient) dial(ctx context.Context, targetRPCAddr string) (*grp
 		}),
 	)
 }
+
+type sendTask struct {
+	data     ReportData
+	deadline time.Time
+}
diff --git a/util/topsql/topsql.go b/util/topsql/topsql.go
index 5a458b4a21f3f..67ceb242039b5 100644
--- a/util/topsql/topsql.go
+++ b/util/topsql/topsql.go
@@ -40,8 +40,8 @@ var globalTopSQLReport reporter.TopSQLReporter
 
 // SetupTopSQL sets up the top-sql worker.
 func SetupTopSQL() {
-	rc := reporter.NewGRPCReportClient(plancodec.DecodeNormalizedPlan)
-	globalTopSQLReport = reporter.NewRemoteTopSQLReporter(rc)
+	ds := reporter.NewSingleTargetDataSink(plancodec.DecodeNormalizedPlan)
+	globalTopSQLReport = reporter.NewRemoteTopSQLReporter(ds)
 	tracecpu.GlobalSQLCPUProfiler.SetCollector(globalTopSQLReport)
 	tracecpu.GlobalSQLCPUProfiler.Run()
 }
diff --git a/util/topsql/topsql_test.go b/util/topsql/topsql_test.go
index 616095231bfbe..d9ec6799194d7 100644
--- a/util/topsql/topsql_test.go
+++ b/util/topsql/topsql_test.go
@@ -115,7 +115,7 @@ func TestTopSQLReporter(t *testing.T) {
 		conf.TopSQL.ReceiverAddress = server.Address()
 	})
 
-	client := reporter.NewGRPCReportClient(mockPlanBinaryDecoderFunc)
+	client := reporter.NewSingleTargetDataSink(mockPlanBinaryDecoderFunc)
 	report := reporter.NewRemoteTopSQLReporter(client)
 	defer report.Close()
 
diff --git a/util/vitess/vitess_hash_test.go b/util/vitess/vitess_hash_test.go
index 769c0d5c0cc4f..7e6587b2007a9 100644
--- a/util/vitess/vitess_hash_test.go
+++ b/util/vitess/vitess_hash_test.go
@@ -25,8 +25,6 @@ import (
 )
 
 func TestVitessHash(t *testing.T) {
-	t.Parallel()
-
 	hashed, err := HashUint64(30375298039)
 	require.NoError(t, err)
 	require.Equal(t, "031265661E5F1133", toHex(hashed))
diff --git a/util/wait_group_wrapper_test.go b/util/wait_group_wrapper_test.go
index ea915fba64813..40e66fdaf5759 100644
--- a/util/wait_group_wrapper_test.go
+++ b/util/wait_group_wrapper_test.go
@@ -22,7 +22,6 @@ import (
 )
 
 func TestWaitGroupWrapperRun(t *testing.T) {
-	t.Parallel()
 	var expect int32 = 4
 	var val atomic.Int32
 	var wg WaitGroupWrapper
@@ -36,7 +35,6 @@ func TestWaitGroupWrapperRun(t *testing.T) {
 }
 
 func TestWaitGroupWrapperRunWithRecover(t *testing.T) {
-	t.Parallel()
 	var expect int32 = 2
 	var val atomic.Int32
 	var wg WaitGroupWrapper