diff --git a/planner/core/explain.go b/planner/core/explain.go
index d0ae474b79e7f..0c68326b00a01 100644
--- a/planner/core/explain.go
+++ b/planner/core/explain.go
@@ -431,7 +431,7 @@ func (p *PhysicalIndexReader) ExplainInfo() string {
 
 // ExplainNormalizedInfo implements Plan interface.
 func (p *PhysicalIndexReader) ExplainNormalizedInfo() string {
-	return p.ExplainInfo()
+	return "index:" + p.indexPlan.TP()
 }
 
 func (p *PhysicalIndexReader) accessObject(sctx sessionctx.Context) string {
diff --git a/planner/core/plan_test.go b/planner/core/plan_test.go
index 288444c9f2c12..5dc6b8a5a1ac4 100644
--- a/planner/core/plan_test.go
+++ b/planner/core/plan_test.go
@@ -21,6 +21,7 @@ import (
 	"testing"
 
 	. "github.com/pingcap/check"
+	"github.com/pingcap/failpoint"
 	"github.com/pingcap/tidb/config"
 	"github.com/pingcap/tidb/domain"
 	"github.com/pingcap/tidb/kv"
@@ -35,7 +36,7 @@ import (
 	"github.com/pingcap/tidb/util/testutil"
 )
 
-var _ = Suite(&testPlanNormalize{})
+var _ = SerialSuites(&testPlanNormalize{})
 
 type testPlanNormalize struct {
 	store kv.Storage
@@ -286,6 +287,14 @@ func (s *testPlanNormalize) TestNormalizedDigest(c *C) {
 	   s_dist_10  char(24) DEFAULT NULL,
 	  PRIMARY KEY ( s_w_id , s_i_id )
 	);`)
+
+	err := failpoint.Enable("github.com/pingcap/tidb/planner/mockRandomPlanID", "return(true)")
+	c.Assert(err, IsNil)
+	defer func() {
+		err = failpoint.Disable("github.com/pingcap/tidb/planner/mockRandomPlanID")
+		c.Assert(err, IsNil)
+	}()
+
 	normalizedDigestCases := []struct {
 		sql1   string
 		sql2   string
@@ -404,7 +413,6 @@ func (s *testPlanNormalize) TestNormalizedDigest(c *C) {
 }
 
 func testNormalizeDigest(tk *testkit.TestKit, c *C, sql1, sql2 string, isSame bool) {
-	tk.Se.GetSessionVars().PlanID = 0
 	tk.MustQuery(sql1)
 	info := tk.Se.ShowProcess()
 	c.Assert(info, NotNil)
@@ -412,7 +420,6 @@ func testNormalizeDigest(tk *testkit.TestKit, c *C, sql1, sql2 string, isSame bo
 	c.Assert(ok, IsTrue)
 	normalized1, digest1 := core.NormalizePlan(physicalPlan)
 
-	tk.Se.GetSessionVars().PlanID = 0
 	tk.MustQuery(sql2)
 	info = tk.Se.ShowProcess()
 	c.Assert(info, NotNil)
diff --git a/planner/core/testdata/plan_normalized_suite_out.json b/planner/core/testdata/plan_normalized_suite_out.json
index 8c656d9b60b40..ec97aea6b15b6 100644
--- a/planner/core/testdata/plan_normalized_suite_out.json
+++ b/planner/core/testdata/plan_normalized_suite_out.json
@@ -47,7 +47,7 @@
         "SQL": "select a+1,b+2 from t1 use index(b) where b=3",
         "Plan": [
           " Projection         root plus(test.t1.a, ?), plus(test.t1.b, ?)",
-          " └─IndexReader      root index:IndexRangeScan_5",
+          " └─IndexReader      root index:IndexRangeScan",
           "   └─IndexRangeScan cop  table:t1, index:b(b), range:[?,?], keep order:false"
         ]
       },
diff --git a/planner/optimize.go b/planner/optimize.go
index bd610664f4bd4..d111e078ab917 100644
--- a/planner/optimize.go
+++ b/planner/optimize.go
@@ -18,6 +18,7 @@ import (
 	"context"
 	"fmt"
 	"math"
+	"math/rand"
 	"runtime/trace"
 	"strings"
 	"sync"
@@ -316,6 +317,10 @@ func optimize(ctx context.Context, sctx sessionctx.Context, node ast.Node, is in
 	hintProcessor := &hint.BlockHintProcessor{Ctx: sctx}
 	node.Accept(hintProcessor)
 
+	failpoint.Inject("mockRandomPlanID", func() {
+		sctx.GetSessionVars().PlanID = rand.Intn(1000) // nolint:gosec
+	})
+
 	builder := planBuilderPool.Get().(*plannercore.PlanBuilder)
 	defer planBuilderPool.Put(builder.ResetForReuse())