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

executor/admin.go

@@ -30,6 +30,7 @@ import (
 	"github.com/pingcap/tidb/types"
 	"github.com/pingcap/tidb/util/chunk"
 	"github.com/pingcap/tidb/util/ranger"
+	"github.com/pingcap/tidb/util/timeutil"
 	"github.com/pingcap/tipb/go-tipb"
 	"github.com/pkg/errors"
 	log "github.com/sirupsen/logrus"
@@ -125,7 +126,7 @@ func (e *CheckIndexRangeExec) Open(ctx context.Context) error {
 func (e *CheckIndexRangeExec) buildDAGPB() (*tipb.DAGRequest, error) {
 	dagReq := &tipb.DAGRequest{}
 	dagReq.StartTs = e.ctx.Txn().StartTS()
-	dagReq.TimeZoneName, dagReq.TimeZoneOffset = zone(e.ctx)
+	dagReq.TimeZoneName, dagReq.TimeZoneOffset = timeutil.Zone(e.ctx.GetSessionVars().Location())
 	sc := e.ctx.GetSessionVars().StmtCtx
 	dagReq.Flags = statementContextToFlags(sc)
 	for i := range e.schema.Columns {
@@ -223,7 +224,7 @@ func (e *RecoverIndexExec) constructLimitPB(count uint64) *tipb.Executor {
 func (e *RecoverIndexExec) buildDAGPB(txn kv.Transaction, limitCnt uint64) (*tipb.DAGRequest, error) {
 	dagReq := &tipb.DAGRequest{}
 	dagReq.StartTs = txn.StartTS()
-	dagReq.TimeZoneName, dagReq.TimeZoneOffset = zone(e.ctx)
+	dagReq.TimeZoneName, dagReq.TimeZoneOffset = timeutil.Zone(e.ctx.GetSessionVars().Location())
 	sc := e.ctx.GetSessionVars().StmtCtx
 	dagReq.Flags = statementContextToFlags(sc)
 	for i := range e.columns {
@@ -651,7 +652,7 @@ func (e *CleanupIndexExec) Open(ctx context.Context) error {
 func (e *CleanupIndexExec) buildIdxDAGPB(txn kv.Transaction) (*tipb.DAGRequest, error) {
 	dagReq := &tipb.DAGRequest{}
 	dagReq.StartTs = txn.StartTS()
-	dagReq.TimeZoneName, dagReq.TimeZoneOffset = zone(e.ctx)
+	dagReq.TimeZoneName, dagReq.TimeZoneOffset = timeutil.Zone(e.ctx.GetSessionVars().Location())
 	sc := e.ctx.GetSessionVars().StmtCtx
 	dagReq.Flags = statementContextToFlags(sc)
 	for i := range e.idxCols {

executor/builder.go

@@ -43,6 +43,7 @@ import (
 	"github.com/pingcap/tidb/util/admin"
 	"github.com/pingcap/tidb/util/chunk"
 	"github.com/pingcap/tidb/util/ranger"
+	"github.com/pingcap/tidb/util/timeutil"
 	"github.com/pingcap/tipb/go-tipb"
 	"github.com/pkg/errors"
 	"golang.org/x/net/context"
@@ -1320,7 +1321,7 @@ func (b *executorBuilder) buildDelete(v *plan.Delete) Executor {
 }
 
 func (b *executorBuilder) buildAnalyzeIndexPushdown(task plan.AnalyzeIndexTask, maxNumBuckets uint64) *AnalyzeIndexExec {
-	_, offset := zone(b.ctx)
+	_, offset := timeutil.Zone(b.ctx.GetSessionVars().Location())
 	e := &AnalyzeIndexExec{
 		ctx:             b.ctx,
 		physicalTableID: task.PhysicalTableID,
@@ -1353,7 +1354,7 @@ func (b *executorBuilder) buildAnalyzeColumnsPushdown(task plan.AnalyzeColumnsTa
 		cols = append([]*model.ColumnInfo{task.PKInfo}, cols...)
 	}
 
-	_, offset := zone(b.ctx)
+	_, offset := timeutil.Zone(b.ctx.GetSessionVars().Location())
 	e := &AnalyzeColumnsExec{
 		ctx:             b.ctx,
 		physicalTableID: task.PhysicalTableID,
@@ -1430,7 +1431,7 @@ func constructDistExec(sctx sessionctx.Context, plans []plan.PhysicalPlan) ([]*t
 func (b *executorBuilder) constructDAGReq(plans []plan.PhysicalPlan) (dagReq *tipb.DAGRequest, streaming bool, err error) {
 	dagReq = &tipb.DAGRequest{}
 	dagReq.StartTs = b.getStartTS()
-	dagReq.TimeZoneName, dagReq.TimeZoneOffset = zone(b.ctx)
+	dagReq.TimeZoneName, dagReq.TimeZoneOffset = timeutil.Zone(b.ctx.GetSessionVars().Location())
 	sc := b.ctx.GetSessionVars().StmtCtx
 	dagReq.Flags = statementContextToFlags(sc)
 	dagReq.Executors, streaming, err = constructDistExec(b.ctx, plans)

executor/distsql.go

@@ -19,7 +19,6 @@ import (
 	"sort"
 	"sync"
 	"sync/atomic"
-	"time"
 	"unsafe"
 
 	"github.com/pingcap/tidb/distsql"
@@ -117,22 +116,6 @@ func closeAll(objs ...Closeable) error {
 	return errors.Trace(err)
 }
 
-// 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
-// returning `Local` when `loc` is `time.Local`. We need keep an eye on this.
-func zone(sctx sessionctx.Context) (string, int64) {
-	loc := sctx.GetSessionVars().Location()
-	_, offset := time.Now().In(loc).Zone()
-	var name string
-	name = loc.String()
-	if name == "Local" {
-		name = "System"
-	}
-
-	return name, int64(offset)
-}
-
 // statementContextToFlags converts StatementContext to tipb.SelectRequest.Flags.
 func statementContextToFlags(sc *stmtctx.StatementContext) uint64 {
 	var flags uint64

executor/executor_test.go

@@ -26,6 +26,7 @@ import (
 	"time"
 
 	gofail "github.com/etcd-io/gofail/runtime"
+	"github.com/golang/protobuf/proto"
 	. "github.com/pingcap/check"
 	pb "github.com/pingcap/kvproto/pkg/kvrpcpb"
 	"github.com/pingcap/tidb/config"
@@ -58,6 +59,8 @@ import (
 	"github.com/pingcap/tidb/util/testkit"
 	"github.com/pingcap/tidb/util/testleak"
 	"github.com/pingcap/tidb/util/testutil"
+	"github.com/pingcap/tidb/util/timeutil"
+	"github.com/pingcap/tipb/go-tipb"
 	"github.com/pkg/errors"
 	"golang.org/x/net/context"
 )
@@ -2357,6 +2360,32 @@ func (s *testContextOptionSuite) TestCoprocessorPriority(c *C) {
 	cli.mu.Unlock()
 }
 
+func (s *testSuite) TestTimezonePushDown(c *C) {
+	tk := testkit.NewTestKit(c, s.store)
+	tk.MustExec("use test")
+	tk.MustExec("create table t (ts timestamp)")
+	defer tk.MustExec("drop table t")
+	tk.MustExec(`insert into t values ("2018-09-13 10:02:06")`)
+
+	systemTZ := timeutil.Local()
+	c.Assert(systemTZ.String(), Not(Equals), "System")
+	ctx := context.Background()
+	count := 0
+	ctx1 := context.WithValue(ctx, "CheckSelectRequestHook", func(req *kv.Request) {
+		count += 1
+		dagReq := new(tipb.DAGRequest)
+		err := proto.Unmarshal(req.Data, dagReq)
+		c.Assert(err, IsNil)
+		c.Assert(dagReq.GetTimeZoneName(), Equals, systemTZ.String())
+	})
+	tk.Se.Execute(ctx1, `select * from t where ts = "2018-09-13 10:02:06"`)
+
+	tk.MustExec(`set time_zone="System"`)
+	tk.Se.Execute(ctx1, `select * from t where ts = "2018-09-13 10:02:06"`)
+
+	c.Assert(count, Equals, 2) // Make sure the hook function is called.
+}
+
 func (s *testSuite) TestNotFillCacheFlag(c *C) {
 	tk := testkit.NewTestKit(c, s.store)
 	tk.MustExec("use test")

expression/builtin_time_test.go

@@ -31,6 +31,7 @@ import (
 	"github.com/pingcap/tidb/util/mock"
 	"github.com/pingcap/tidb/util/testleak"
 	"github.com/pingcap/tidb/util/testutil"
+	"github.com/pingcap/tidb/util/timeutil"
 	"github.com/pkg/errors"
 )
 
@@ -997,7 +998,7 @@ func (s *testEvaluatorSuite) TestSysDate(c *C) {
 	fc := funcs[ast.Sysdate]
 
 	ctx := mock.NewContext()
-	ctx.GetSessionVars().StmtCtx.TimeZone = time.Local
+	ctx.GetSessionVars().StmtCtx.TimeZone = timeutil.Local()
 	timezones := []types.Datum{types.NewDatum(1234), types.NewDatum(0)}
 	for _, timezone := range timezones {
 		// sysdate() result is not affected by "timestamp" session variable.

session/bootstrap.go

@@ -32,6 +32,7 @@ import (
 	"github.com/pingcap/tidb/terror"
 	"github.com/pingcap/tidb/util/auth"
 	"github.com/pingcap/tidb/util/chunk"
+	"github.com/pingcap/tidb/util/timeutil"
 	"github.com/pkg/errors"
 	log "github.com/sirupsen/logrus"
 	"golang.org/x/net/context"
@@ -233,7 +234,10 @@ const (
 	bootstrappedVarTrue = "True"
 	// The variable name in mysql.TiDB table.
 	// It is used for getting the version of the TiDB server which bootstrapped the store.
-	tidbServerVersionVar = "tidb_server_version" //
+	tidbServerVersionVar = "tidb_server_version"
+	// The variable name in mysql.tidb table and it will be used when we want to know
+	// system timezone.
+	tidbSystemTZ = "system_tz"
 	// Const for TiDB server version 2.
 	version2  = 2
 	version3  = 3
@@ -257,6 +261,7 @@ const (
 	version21 = 21
 	version22 = 22
 	version23 = 23
+	version24 = 24
 )
 
 func checkBootstrapped(s Session) (bool, error) {
@@ -407,6 +412,10 @@ func upgrade(s Session) {
 		upgradeToVer23(s)
 	}
 
+	if ver < version24 {
+		upgradeToVer24(s)
+	}
+
 	updateBootstrapVer(s)
 	_, err = s.Execute(context.Background(), "COMMIT")
 
@@ -649,6 +658,18 @@ func upgradeToVer23(s Session) {
 	doReentrantDDL(s, "ALTER TABLE mysql.stats_histograms ADD COLUMN `flag` bigint(64) NOT NULL DEFAULT 0", infoschema.ErrColumnExists)
 }
 
+// writeSystemTZ writes system timezone info into mysql.tidb
+func writeSystemTZ(s Session) {
+	sql := fmt.Sprintf(`INSERT HIGH_PRIORITY INTO %s.%s VALUES ("%s", "%s", "TiDB Global System Timezone.") ON DUPLICATE KEY UPDATE VARIABLE_VALUE="%s"`,
+		mysql.SystemDB, mysql.TiDBTable, tidbSystemTZ, timeutil.InferSystemTZ(), timeutil.InferSystemTZ())
+	mustExecute(s, sql)
+}
+
+// upgradeToVer24 initializes `System` timezone according to docs/design/2018-09-10-adding-tz-env.md
+func upgradeToVer24(s Session) {
+	writeSystemTZ(s)
+}
+
 // updateBootstrapVer updates bootstrap version variable in mysql.TiDB table.
 func updateBootstrapVer(s Session) {
 	// Update bootstrap version.
@@ -732,6 +753,7 @@ func doDMLWorks(s Session) {
 		mysql.SystemDB, mysql.TiDBTable, tidbServerVersionVar, currentBootstrapVersion)
 	mustExecute(s, sql)
 
+	writeSystemTZ(s)
 	_, err := s.Execute(context.Background(), "COMMIT")
 	if err != nil {
 		time.Sleep(1 * time.Second)

session/session.go

@@ -53,6 +53,7 @@ import (
 	"github.com/pingcap/tidb/util/charset"
 	"github.com/pingcap/tidb/util/chunk"
 	"github.com/pingcap/tidb/util/kvcache"
+	"github.com/pingcap/tidb/util/timeutil"
 	binlog "github.com/pingcap/tipb/go-binlog"
 	"github.com/pkg/errors"
 	log "github.com/sirupsen/logrus"
@@ -1068,6 +1069,20 @@ func CreateSession(store kv.Storage) (Session, error) {
 	return s, nil
 }
 
+// loadSystemTZ loads systemTZ from mysql.tidb
+func loadSystemTZ(se *session) (string, error) {
+	sql := `select variable_value from mysql.tidb where variable_name = "system_tz"`
+	rss, errLoad := se.Execute(context.Background(), sql)
+	if errLoad != nil {
+		return "", errLoad
+	}
+	// the record of mysql.tidb under where condition: variable_name = "system_tz" should shall only be one.
+	defer rss[0].Close()
+	chk := rss[0].NewChunk()
+	rss[0].Next(context.Background(), chk)
+	return chk.GetRow(0).GetString(0), nil
+}
+
 // BootstrapSession runs the first time when the TiDB server start.
 func BootstrapSession(store kv.Storage) (*domain.Domain, error) {
 	ver := getStoreBootstrapVersion(store)
@@ -1081,11 +1096,20 @@ func BootstrapSession(store kv.Storage) (*domain.Domain, error) {
 	if err != nil {
 		return nil, errors.Trace(err)
 	}
+	// get system tz from mysql.tidb
+	tz, err := loadSystemTZ(se)
+	if err != nil {
+		return nil, errors.Trace(err)
+	}
+
+	timeutil.SetSystemTZ(tz)
+
 	dom := domain.GetDomain(se)
 	err = dom.LoadPrivilegeLoop(se)
 	if err != nil {
 		return nil, errors.Trace(err)
 	}
+
 	se1, err := createSession(store)
 	if err != nil {
 		return nil, errors.Trace(err)
@@ -1180,7 +1204,7 @@ func createSessionWithDomain(store kv.Storage, dom *domain.Domain) (*session, er
 
 const (
 	notBootstrapped         = 0
-	currentBootstrapVersion = 23
+	currentBootstrapVersion = 24
 )
 
 func getStoreBootstrapVersion(store kv.Storage) int64 {

sessionctx/variable/session.go

@@ -29,6 +29,7 @@ import (
 	"github.com/pingcap/tidb/types"
 	"github.com/pingcap/tidb/util/auth"
 	"github.com/pingcap/tidb/util/chunk"
+	"github.com/pingcap/tidb/util/timeutil"
 	"github.com/pkg/errors"
 )
 
@@ -426,7 +427,7 @@ func (s *SessionVars) GetNextPreparedStmtID() uint32 {
 func (s *SessionVars) Location() *time.Location {
 	loc := s.TimeZone
 	if loc == nil {
-		loc = time.Local
+		loc = timeutil.Local()
 	}
 	return loc
 }

sessionctx/variable/varsutil.go

@@ -25,6 +25,7 @@ import (
 	"github.com/pingcap/tidb/config"
 	"github.com/pingcap/tidb/mysql"
 	"github.com/pingcap/tidb/types"
+	"github.com/pingcap/tidb/util/timeutil"
 	"github.com/pkg/errors"
 )
 
@@ -350,8 +351,7 @@ func tidbOptInt64(opt string, defaultVal int64) int64 {
 
 func parseTimeZone(s string) (*time.Location, error) {
 	if strings.EqualFold(s, "SYSTEM") {
-		// TODO: Support global time_zone variable, it should be set to global time_zone value.
-		return time.Local, nil
+		return timeutil.Local(), nil
 	}
 
 	loc, err := time.LoadLocation(s)