diff --git a/evaluator/builtin_time.go b/evaluator/builtin_time.go
index b28778191f..baacb77d05 100644
--- a/evaluator/builtin_time.go
+++ b/evaluator/builtin_time.go
@@ -184,7 +184,7 @@ func builtinNow(args []types.Datum, _ context.Context) (d types.Datum, err error
 		d.SetNull()
 		return d, errors.Trace(err)
 	}
-	d.SetMysqlTime(tr)
+	d.SetMysqlTime(&tr)
 	return d, nil
 }
 
@@ -373,7 +373,7 @@ func builtinCurrentDate(args []types.Datum, _ context.Context) (d types.Datum, e
 	t := mysql.Time{
 		Time: time.Date(year, month, day, 0, 0, 0, 0, time.Local),
 		Type: mysql.TypeDate, Fsp: 0}
-	d.SetMysqlTime(t)
+	d.SetMysqlTime(&t)
 	return d, nil
 }
 
diff --git a/mysql/time.go b/mysql/time.go
index 7f98199415..678a5bc34f 100644
--- a/mysql/time.go
+++ b/mysql/time.go
@@ -280,7 +280,10 @@ func (t Time) ConvertToDuration() (Duration, error) {
 
 // Compare returns an integer comparing the time instant t to o.
 // If t is after o, return 1, equal o, return 0, before o, return -1.
-func (t Time) Compare(o Time) int {
+func (t *Time) Compare(o *Time) int {
+	if o == nil {
+		return 1
+	}
 	if t.Time.After(o.Time) {
 		return 1
 	} else if t.Time.Equal(o.Time) {
@@ -299,7 +302,7 @@ func (t Time) CompareString(str string) (int, error) {
 		return 0, errors.Trace(err)
 	}
 
-	return t.Compare(o), nil
+	return t.Compare(&o), nil
 }
 
 // RoundFrac rounds fractional seconds precision with new fsp and returns a new one.
@@ -1027,7 +1030,10 @@ func checkTimestamp(t Time) bool {
 }
 
 // ExtractTimeNum extracts time value number from time unit and format.
-func ExtractTimeNum(unit string, t Time) (int64, error) {
+func ExtractTimeNum(unit string, t *Time) (int64, error) {
+	if t == nil {
+		return 0, errors.Errorf("invalid time t")
+	}
 	switch strings.ToUpper(unit) {
 	case "MICROSECOND":
 		return int64(t.Nanosecond() / 1000), nil
diff --git a/tidb-server/server/util.go b/tidb-server/server/util.go
index 4d6c76d3d7..c143f48bf3 100644
--- a/tidb-server/server/util.go
+++ b/tidb-server/server/util.go
@@ -293,7 +293,7 @@ func dumpRowValuesBinary(alloc arena.Allocator, columns []*ColumnInfo, row []typ
 		case types.KindMysqlDecimal:
 			data = append(data, dumpLengthEncodedString(hack.Slice(val.GetMysqlDecimal().String()), alloc)...)
 		case types.KindMysqlTime:
-			data = append(data, dumpBinaryDateTime(val.GetMysqlTime(), nil)...)
+			data = append(data, dumpBinaryDateTime(*val.GetMysqlTime(), nil)...)
 		case types.KindMysqlDuration:
 			data = append(data, dumpBinaryTime(val.GetMysqlDuration().Duration)...)
 		case types.KindMysqlSet:
diff --git a/util/types/datum.go b/util/types/datum.go
index fc5744e8be..6d038342ed 100644
--- a/util/types/datum.go
+++ b/util/types/datum.go
@@ -233,12 +233,12 @@ func (d *Datum) SetMysqlSet(b mysql.Set) {
 }
 
 // GetMysqlTime gets mysql.Time value
-func (d *Datum) GetMysqlTime() mysql.Time {
-	return d.x.(mysql.Time)
+func (d *Datum) GetMysqlTime() *mysql.Time {
+	return d.x.(*mysql.Time)
 }
 
 // SetMysqlTime sets mysql.Time value
-func (d *Datum) SetMysqlTime(b mysql.Time) {
+func (d *Datum) SetMysqlTime(b *mysql.Time) {
 	d.k = KindMysqlTime
 	d.x = b
 }
@@ -258,6 +258,8 @@ func (d *Datum) GetValue() interface{} {
 		return d.GetString()
 	case KindBytes:
 		return d.GetBytes()
+	case KindMysqlTime:
+		return *d.GetMysqlTime()
 	default:
 		return d.x
 	}
@@ -306,9 +308,10 @@ func (d *Datum) SetValue(val interface{}) {
 	case mysql.Set:
 		d.x = x
 		d.k = KindMysqlSet
+	case *mysql.Time:
+		d.SetMysqlTime(x)
 	case mysql.Time:
-		d.x = x
-		d.k = KindMysqlTime
+		d.SetMysqlTime(&x)
 	case []Datum:
 		d.x = x
 		d.k = KindRow
@@ -458,7 +461,7 @@ func (d *Datum) compareString(s string) (int, error) {
 		return d.GetMysqlDecimal().Cmp(dec), err
 	case KindMysqlTime:
 		dt, err := mysql.ParseDatetime(s)
-		return d.GetMysqlTime().Compare(dt), err
+		return d.GetMysqlTime().Compare(&dt), err
 	case KindMysqlDuration:
 		dur, err := mysql.ParseDuration(s, mysql.MaxFsp)
 		return d.GetMysqlDuration().Compare(dur), err
@@ -544,7 +547,10 @@ func (d *Datum) compareMysqlSet(set mysql.Set) (int, error) {
 	}
 }
 
-func (d *Datum) compareMysqlTime(time mysql.Time) (int, error) {
+func (d *Datum) compareMysqlTime(time *mysql.Time) (int, error) {
+	if time == nil {
+		return 0, errors.Errorf("invalid time t")
+	}
 	switch d.k {
 	case KindString, KindBytes:
 		dt, err := mysql.ParseDatetime(d.GetString())