server: set system_time_zone from system_tz

server/server.go

@@ -59,6 +59,7 @@ import (
 	"github.com/pingcap/tidb/util"
 	"github.com/pingcap/tidb/util/logutil"
 	"github.com/pingcap/tidb/util/sys/linux"
+	"github.com/pingcap/tidb/util/timeutil"
 	"go.uber.org/zap"
 	"google.golang.org/grpc"
 )
@@ -209,6 +210,7 @@ func NewServer(cfg *config.Config, driver IDriver) (*Server, error) {
 		stopListenerCh:    make(chan struct{}, 1),
 	}
 	s.loadTLSCertificates()
+	setSystemTimeZoneVariable()
 
 	s.capability = defaultCapability
 	if s.tlsConfig != nil {
@@ -622,6 +624,18 @@ func (s *Server) kickIdleConnection() {
 	}
 }
 
+func setSystemTimeZoneVariable() {
+	tz, err := timeutil.GetSystemTZ()
+	if err != nil {
+		logutil.BgLogger().Error(
+			"Error getting SystemTZ, use default value instead",
+			zap.Error(err),
+			zap.String("default system_time_zone", variable.SysVars["system_time_zone"].Value))
+		return
+	}
+	variable.SysVars["system_time_zone"].Value = tz
+}
+
 // Server error codes.
 const (
 	codeUnknownFieldType = 1

server/tidb_test.go

@@ -37,6 +37,7 @@ import (
 	"github.com/pingcap/tidb/metrics"
 	"github.com/pingcap/tidb/session"
 	"github.com/pingcap/tidb/store/mockstore"
+	"github.com/pingcap/tidb/util/testkit"
 )
 
 type TidbTestSuite struct {
@@ -293,6 +294,19 @@ func registerTLSConfig(configName string, caCertPath string, clientCertPath stri
 	return nil
 }
 
+func (ts *TidbTestSuite) TestSystemTimeZone(c *C) {
+	tk := testkit.NewTestKit(c, ts.store)
+	cfg := config.NewConfig()
+	cfg.Port = 4002
+	cfg.Status.ReportStatus = false
+	server, err := NewServer(cfg, ts.tidbdrv)
+	c.Assert(err, IsNil)
+	defer server.Close()
+
+	tz1 := tk.MustQuery("select variable_value from mysql.tidb where variable_name = 'system_tz'").Rows()
+	tk.MustQuery("select @@system_time_zone").Check(tz1)
+}
+
 func (ts *TidbTestSuite) TestTLS(c *C) {
 	// Generate valid TLS certificates.
 	caCert, caKey, err := generateCert(0, "TiDB CA", nil, nil, "/tmp/ca-key.pem", "/tmp/ca-cert.pem")

util/timeutil/time.go

@@ -117,6 +117,14 @@ func SetSystemTZ(name string) {
 	})
 }
 
+// GetSystemTZ gets the value of systemTZ, an error is returned if systemTZ is not properly set.
+func GetSystemTZ() (string, error) {
+	if systemTZ == "System" || systemTZ == "" {
+		return "", fmt.Errorf("variable `systemTZ` is not properly set")
+	}
+	return systemTZ, nil
+}
+
 // getLoc first trying to load location from a cache map. If nothing found in such map, then call
 // `time.LoadLocation` to get a timezone location. After trying both way, an error will be returned
 //  if valid Location is not found.