fix default current_timestamp calculation not consistent with now() f…

…unction results

refactor related statement time related interface and some time function implementations

executor/write_test.go

@@ -2538,3 +2538,15 @@ func (s *testSuite4) TestSetWithRefGenCol(c *C) {
 	_, err = tk.Exec(`insert into t3 set j = i + 1`)
 	c.Assert(err, NotNil)
 }
+
+func (s *testSuite4) TestSetWithCurrentTimestampAndNow(c *C) {
+	tk := testkit.NewTestKitWithInit(c, s.store)
+	tk.MustExec("use test")
+	tk.MustExec(`drop table if exists tbl;`)
+	tk.MustExec(`create table t1(c1 timestamp default current_timestamp, c2 int, c3 timestamp default current_timestamp);`)
+	//c1 insert using now() function result, c3 using default value calculation, should be same
+	tk.MustExec(`insert into t1 set c1 = current_timestamp, c2 = sleep(2);`)
+	tk.MustQuery("select c1 = c3 from t1").Check(testkit.Rows("1"))
+	tk.MustExec(`insert into t1 set c1 = current_timestamp, c2 = sleep(1);`)
+	tk.MustQuery("select c1 = c3 from t1").Check(testkit.Rows("1", "1"))
+}

expression/builtin_time.go

@@ -2028,9 +2028,9 @@ func (b *builtinCurrentDateSig) Clone() builtinFunc {
 // See https://dev.mysql.com/doc/refman/5.7/en/date-and-time-functions.html#function_curdate
 func (b *builtinCurrentDateSig) evalTime(row chunk.Row) (d types.Time, isNull bool, err error) {
 	tz := b.ctx.GetSessionVars().Location()
-	var nowTs = &b.ctx.GetSessionVars().StmtCtx.NowTs
-	if nowTs.Equal(time.Time{}) {
-		*nowTs = time.Now()
+	nowTs, err := getStmtTimestamp(b.ctx)
+	if err != nil {
+		return types.Time{}, true, err
 	}
 	year, month, day := nowTs.In(tz).Date()
 	result := types.Time{
@@ -2087,9 +2087,9 @@ func (b *builtinCurrentTime0ArgSig) Clone() builtinFunc {
 
 func (b *builtinCurrentTime0ArgSig) evalDuration(row chunk.Row) (types.Duration, bool, error) {
 	tz := b.ctx.GetSessionVars().Location()
-	var nowTs = &b.ctx.GetSessionVars().StmtCtx.NowTs
-	if nowTs.Equal(time.Time{}) {
-		*nowTs = time.Now()
+	nowTs, err := getStmtTimestamp(b.ctx)
+	if err != nil {
+		return types.Duration{}, true, err
 	}
 	dur := nowTs.In(tz).Format(types.TimeFormat)
 	res, err := types.ParseDuration(b.ctx.GetSessionVars().StmtCtx, dur, types.MinFsp)
@@ -2115,9 +2115,9 @@ func (b *builtinCurrentTime1ArgSig) evalDuration(row chunk.Row) (types.Duration,
 		return types.Duration{}, true, err
 	}
 	tz := b.ctx.GetSessionVars().Location()
-	var nowTs = &b.ctx.GetSessionVars().StmtCtx.NowTs
-	if nowTs.Equal(time.Time{}) {
-		*nowTs = time.Now()
+	nowTs, err := getStmtTimestamp(b.ctx)
+	if err != nil {
+		return types.Duration{}, true, err
 	}
 	dur := nowTs.In(tz).Format(types.TimeFSPFormat)
 	res, err := types.ParseDuration(b.ctx.GetSessionVars().StmtCtx, dur, int(fsp))
@@ -2257,9 +2257,9 @@ func (b *builtinUTCDateSig) Clone() builtinFunc {
 // evalTime evals UTC_DATE, UTC_DATE().
 // See https://dev.mysql.com/doc/refman/5.7/en/date-and-time-functions.html#function_utc-date
 func (b *builtinUTCDateSig) evalTime(row chunk.Row) (types.Time, bool, error) {
-	var nowTs = &b.ctx.GetSessionVars().StmtCtx.NowTs
-	if nowTs.Equal(time.Time{}) {
-		*nowTs = time.Now()
+	nowTs, err := getStmtTimestamp(b.ctx)
+	if err != nil {
+		return types.Time{}, true, err
 	}
 	year, month, day := nowTs.UTC().Date()
 	result := types.Time{
@@ -2318,9 +2318,9 @@ func (c *utcTimestampFunctionClass) getFunction(ctx sessionctx.Context, args []E
 }
 
 func evalUTCTimestampWithFsp(ctx sessionctx.Context, fsp int) (types.Time, bool, error) {
-	var nowTs = &ctx.GetSessionVars().StmtCtx.NowTs
-	if nowTs.Equal(time.Time{}) {
-		*nowTs = time.Now()
+	nowTs, err := getStmtTimestamp(ctx)
+	if err != nil {
+		return types.Time{}, true, err
 	}
 	result, err := convertTimeToMysqlTime(nowTs.UTC(), fsp, types.ModeHalfEven)
 	if err != nil {
@@ -2405,13 +2405,9 @@ func (c *nowFunctionClass) getFunction(ctx sessionctx.Context, args []Expression
 }
 
 func evalNowWithFsp(ctx sessionctx.Context, fsp int) (types.Time, bool, error) {
-	var sysTs = &ctx.GetSessionVars().StmtCtx.SysTs
-	if sysTs.Equal(time.Time{}) {
-		var err error
-		*sysTs, err = getSystemTimestamp(ctx)
-		if err != nil {
-			return types.Time{}, true, err
-		}
+	nowTs, err := getStmtTimestamp(ctx)
+	if err != nil {
+		return types.Time{}, true, err
 	}
 
 	// In MySQL's implementation, now() will truncate the result instead of rounding it.
@@ -2422,7 +2418,7 @@ func evalNowWithFsp(ctx sessionctx.Context, fsp int) (types.Time, bool, error) {
 	//	+----------------------------+-------------------------+---------------------+
 	//	| 2019-03-25 15:57:56.612966 | 2019-03-25 15:57:56.612 | 2019-03-25 15:57:56 |
 	//	+----------------------------+-------------------------+---------------------+
-	result, err := convertTimeToMysqlTime(*sysTs, fsp, types.ModeTruncate)
+	result, err := convertTimeToMysqlTime(nowTs, fsp, types.ModeTruncate)
 	if err != nil {
 		return types.Time{}, true, err
 	}
@@ -4278,11 +4274,11 @@ func (b *builtinUnixTimestampCurrentSig) Clone() builtinFunc {
 // evalInt evals a UNIX_TIMESTAMP().
 // See https://dev.mysql.com/doc/refman/5.7/en/date-and-time-functions.html#function_unix-timestamp
 func (b *builtinUnixTimestampCurrentSig) evalInt(row chunk.Row) (int64, bool, error) {
-	var nowTs = &b.ctx.GetSessionVars().StmtCtx.NowTs
-	if nowTs.Equal(time.Time{}) {
-		*nowTs = time.Now()
+	nowTs, err := getStmtTimestamp(b.ctx)
+	if err != nil {
+		return 0, true, err
 	}
-	dec, err := goTimeToMysqlUnixTimestamp(*nowTs, 1)
+	dec, err := goTimeToMysqlUnixTimestamp(nowTs, 1)
 	if err != nil {
 		return 0, true, err
 	}
@@ -6340,9 +6336,9 @@ func (b *builtinUTCTimeWithoutArgSig) Clone() builtinFunc {
 // evalDuration evals a builtinUTCTimeWithoutArgSig.
 // See https://dev.mysql.com/doc/refman/5.7/en/date-and-time-functions.html#function_utc-time
 func (b *builtinUTCTimeWithoutArgSig) evalDuration(row chunk.Row) (types.Duration, bool, error) {
-	var nowTs = &b.ctx.GetSessionVars().StmtCtx.NowTs
-	if nowTs.Equal(time.Time{}) {
-		*nowTs = time.Now()
+	nowTs, err := getStmtTimestamp(b.ctx)
+	if err != nil {
+		return types.Duration{}, true, err
 	}
 	v, err := types.ParseDuration(b.ctx.GetSessionVars().StmtCtx, nowTs.UTC().Format(types.TimeFormat), 0)
 	return v, false, err
@@ -6371,9 +6367,9 @@ func (b *builtinUTCTimeWithArgSig) evalDuration(row chunk.Row) (types.Duration,
 	if fsp < int64(types.MinFsp) {
 		return types.Duration{}, true, errors.Errorf("Invalid negative %d specified, must in [0, 6].", fsp)
 	}
-	var nowTs = &b.ctx.GetSessionVars().StmtCtx.NowTs
-	if nowTs.Equal(time.Time{}) {
-		*nowTs = time.Now()
+	nowTs, err := getStmtTimestamp(b.ctx)
+	if err != nil {
+		return types.Duration{}, true, err
 	}
 	v, err := types.ParseDuration(b.ctx.GetSessionVars().StmtCtx, nowTs.UTC().Format(types.TimeFSPFormat), int(fsp))
 	return v, false, err

expression/builtin_time_test.go

@@ -764,8 +764,7 @@ func (s *testEvaluatorSuite) TestTime(c *C) {
 }
 
 func resetStmtContext(ctx sessionctx.Context) {
-	ctx.GetSessionVars().StmtCtx.NowTs = time.Time{}
-	ctx.GetSessionVars().StmtCtx.SysTs = time.Time{}
+	ctx.GetSessionVars().StmtCtx.ResetNowTs()
 }
 
 func (s *testEvaluatorSuite) TestNowAndUTCTimestamp(c *C) {

expression/helper.go

@@ -54,7 +54,7 @@ func GetTimeValue(ctx sessionctx.Context, v interface{}, tp byte, fsp int) (d ty
 	case string:
 		upperX := strings.ToUpper(x)
 		if upperX == strings.ToUpper(ast.CurrentTimestamp) {
-			defaultTime, err := getSystemTimestamp(ctx)
+			defaultTime, err := getStmtTimestamp(ctx)
 			if err != nil {
 				return d, err
 			}
@@ -120,7 +120,9 @@ func GetTimeValue(ctx sessionctx.Context, v interface{}, tp byte, fsp int) (d ty
 	return d, nil
 }
 
-func getSystemTimestamp(ctx sessionctx.Context) (time.Time, error) {
+// if timestamp session variable set, use session variable as current time, otherwise use cached time
+// during one sql statement, the "current_time" should be the same
+func getStmtTimestamp(ctx sessionctx.Context) (time.Time, error) {
 	now := time.Now()
 
 	if ctx == nil {
@@ -133,15 +135,16 @@ func getSystemTimestamp(ctx sessionctx.Context) (time.Time, error) {
 		return now, err
 	}
 
-	if timestampStr == "" {
-		return now, nil
-	}
-	timestamp, err := types.StrToInt(sessionVars.StmtCtx, timestampStr)
-	if err != nil {
-		return time.Time{}, err
-	}
-	if timestamp <= 0 {
-		return now, nil
+	if timestampStr != "" {
+		timestamp, err := types.StrToInt(sessionVars.StmtCtx, timestampStr)
+		if err != nil {
+			return time.Time{}, err
+		}
+		if timestamp <= 0 {
+			return now, nil
+		}
+		return time.Unix(timestamp, 0), nil
 	}
-	return time.Unix(timestamp, 0), nil
+	stmtCtx := ctx.GetSessionVars().StmtCtx
+	return stmtCtx.GetNowTsCached(), nil
 }

sessionctx/stmtctx/stmtctx.go

@@ -120,8 +120,8 @@ type StatementContext struct {
 	RuntimeStatsColl *execdetails.RuntimeStatsColl
 	TableIDs         []int64
 	IndexIDs         []int64
-	NowTs            time.Time
-	SysTs            time.Time
+	nowTs            time.Time // use this variable for now/current_timestamp calculation/cache for one stmt
+	stmtTimeCached   bool
 	StmtType         string
 	OriginalSQL      string
 	digestMemo       struct {
@@ -132,6 +132,21 @@ type StatementContext struct {
 	Tables []TableEntry
 }
 
+// GetNowTsCached getter for nowTs, if not set get now time and cache it
+func (sc *StatementContext) GetNowTsCached() time.Time {
+	if !sc.stmtTimeCached {
+		now := time.Now()
+		sc.nowTs = now
+		sc.stmtTimeCached = true
+	}
+	return sc.nowTs
+}
+
+// ResetNowTs resetter for nowTs, clear cached time flag
+func (sc *StatementContext) ResetNowTs() {
+	sc.stmtTimeCached = false
+}
+
 // SQLDigest gets normalized and digest for provided sql.
 // it will cache result after first calling.
 func (sc *StatementContext) SQLDigest() (normalized, sqlDigest string) {