*: write system timezone into mysql.tidb in bootstrap stage.

executor/distsql.go

@@ -15,8 +15,10 @@ package executor
 
 import (
 	"math"
+	"path/filepath"
 	"runtime"
 	"sort"
+	"strings"
 	"sync"
 	"sync/atomic"
 	"time"
@@ -117,6 +119,21 @@ func closeAll(objs ...Closeable) error {
 	return errors.Trace(err)
 }
 
+// GetTZNameFromFileName gets IANA timezone name from zoneinfo path.
+// TODO It will be refined later. This is just a quick fix.
+func GetTZNameFromFileName(path string) (string, error) {
+	// phase1 only support read /etc/localtime which is a softlink to zoneinfo file
+	substr := "share/zoneinfo"
+	if strings.Contains(path, substr) {
+		idx := strings.Index(path, substr)
+		return string(path[idx+len(substr)+1:]), nil
+	}
+	return "", errors.New("only support softlink has share/zoneinfo in the middle" + path)
+}
+
+var localStr string
+var localOnce sync.Once
+
 // zone returns the current timezone name and timezone offset in seconds.
 // In compatible with MySQL, we change `Local` to `System`.
 // TODO: Golang team plan to return system timezone name intead of
@@ -127,7 +144,20 @@ func zone(sctx sessionctx.Context) (string, int64) {
 	var name string
 	name = loc.String()
 	if name == "Local" {
-		name = "System"
+		localOnce.Do(func() {
+			path, err := filepath.EvalSymlinks("/etc/localtime")
+			if err != nil {
+				log.Errorln(err)
+				localStr = "System"
+			}
+			localStr, err = GetTZNameFromFileName(path)
+			if err != nil {
+				log.Errorln(err)
+				localStr = "System"
+			}
+		})
+
+		return localStr, int64(offset)
 	}
 
 	return name, int64(offset)

executor/distsql_test.go

@@ -207,3 +207,9 @@ func (s *testSuite) TestUniqueKeyNullValueSelect(c *C) {
 	res = tk.MustQuery("select * from t where id is null;")
 	res.Check(testkit.Rows("<nil> a", "<nil> b", "<nil> c"))
 }
+
+func (s *testSuite) TestgetTZNameFromFileName(c *C) {
+	tz, err := executor.GetTZNameFromFileName("/user/share/zoneinfo/Asia/Shanghai")
+	c.Assert(err, IsNil)
+	c.Assert(tz, Equals, "Asia/Shanghai")
+}

store/mockstore/mocktikv/cop_handler_dag.go

@@ -169,8 +169,11 @@ func (h *rpcHandler) buildDAGExecutor(req *coprocessor.Request) (*dagContext, ex
 // timezone offset in seconds east of UTC is used to constructed the timezone.
 func constructTimeZone(name string, offset int) (*time.Location, error) {
 	if name != "" {
+		// no need to care about case since name is retreved
+		// from go std library call
 		return LocCache.getLoc(name)
 	}
+
 	return time.FixedZone("", offset), nil
 }