Optimize Date/Date32 scan

lib/column/date.go

@@ -250,9 +250,7 @@ func parseDate(value string, minDate time.Time, maxDate time.Time, location *tim
 		return tv, nil
 	}
 	if tv, err = time.Parse(defaultDateFormatNoZone, value); err == nil {
-		return time.Date(
-			tv.Year(), tv.Month(), tv.Day(), tv.Hour(), tv.Minute(), tv.Second(), tv.Nanosecond(), location,
-		), nil
+		return getTimeWithDifferentLocation(tv, location), nil
 	}
 	return time.Time{}, err
 }
@@ -272,10 +270,10 @@ func (col *Date) Encode(buffer *proto.Buffer) {
 func (col *Date) row(i int) time.Time {
 	t := col.col.Row(i)
 
-	if col.location != nil {
+	if col.location != nil && col.location != time.UTC {
 		// proto.Date is normalized as time.Time with UTC timezone.
 		// We make sure Date return from ClickHouse matches server timezone or user defined location.
-		t = time.Date(t.Year(), t.Month(), t.Day(), t.Hour(), t.Minute(), t.Second(), t.Nanosecond(), col.location)
+		t = getTimeWithDifferentLocation(t, col.location)
 	}
 	return t
 }

lib/column/date32.go

@@ -247,10 +247,10 @@ func (col *Date32) Encode(buffer *proto.Buffer) {
 func (col *Date32) row(i int) time.Time {
 	t := col.col.Row(i)
 
-	if col.location != nil {
+	if col.location != nil && col.location != time.UTC {
 		// proto.Date is normalized as time.Time with UTC timezone.
 		// We make sure Date return from ClickHouse matches server timezone or user defined location.
-		t = time.Date(t.Year(), t.Month(), t.Day(), t.Hour(), t.Minute(), t.Second(), t.Nanosecond(), col.location)
+		t = getTimeWithDifferentLocation(t, col.location)
 	}
 	return t
 }

lib/column/datetime.go

@@ -302,9 +302,7 @@ func (col *DateTime) parseDateTime(value string) (tv time.Time, err error) {
 		return tv, nil
 	}
 	if tv, err = time.Parse(defaultDateTimeFormatNoZone, value); err == nil {
-		return time.Date(
-			tv.Year(), tv.Month(), tv.Day(), tv.Hour(), tv.Minute(), tv.Second(), tv.Nanosecond(), time.Local,
-		), nil
+		return getTimeWithDifferentLocation(tv, time.Local), nil
 	}
 	return time.Time{}, err
 }

lib/column/datetime64.go

@@ -307,9 +307,7 @@ func (col *DateTime64) parseDateTime(value string) (tv time.Time, err error) {
 		return tv, nil
 	}
 	if tv, err = time.Parse(defaultDateTime64FormatNoZone, value); err == nil {
-		return time.Date(
-			tv.Year(), tv.Month(), tv.Day(), tv.Hour(), tv.Minute(), tv.Second(), tv.Nanosecond(), time.Local,
-		), nil
+		return getTimeWithDifferentLocation(tv, time.Local), nil
 	}
 	return time.Time{}, err
 }

lib/column/time_helper.go

@@ -0,0 +1,29 @@
+// Licensed to ClickHouse, Inc. under one or more contributor
+// license agreements. See the NOTICE file distributed with
+// this work for additional information regarding copyright
+// ownership. ClickHouse, Inc. licenses this file to you under
+// the Apache License, Version 2.0 (the "License"); you may
+// not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing,
+// software distributed under the License is distributed on an
+// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+// KIND, either express or implied.  See the License for the
+// specific language governing permissions and limitations
+// under the License.
+
+package column
+
+import "time"
+
+// getTimeWithDifferentLocation returns the same time but with different location, e.g.
+// "2024-08-15 13:22:34 -03:00" will become "2024-08-15 13:22:34 +04:00".
+func getTimeWithDifferentLocation(t time.Time, loc *time.Location) time.Time {
+	year, month, day := t.Date()
+	hour, minute, sec := t.Clock()
+
+	return time.Date(year, month, day, hour, minute, sec, t.Nanosecond(), loc)
+}

lib/column/time_helper_test.go

@@ -0,0 +1,76 @@
+// Licensed to ClickHouse, Inc. under one or more contributor
+// license agreements. See the NOTICE file distributed with
+// this work for additional information regarding copyright
+// ownership. ClickHouse, Inc. licenses this file to you under
+// the Apache License, Version 2.0 (the "License"); you may
+// not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing,
+// software distributed under the License is distributed on an
+// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+// KIND, either express or implied.  See the License for the
+// specific language governing permissions and limitations
+// under the License.
+
+package column
+
+import (
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestGetTimeWithDifferentLocation(t *testing.T) {
+	tests := []struct {
+		in   string
+		loc  *time.Location
+		want string
+	}{
+		{
+			in:   "2023-02-15 14:02:12.321 +00:00",
+			loc:  time.FixedZone("", 60*60),
+			want: "2023-02-15 14:02:12.321 +01:00",
+		},
+		{
+			in:   "2023-02-15 14:02:12.321 +03:00",
+			loc:  time.FixedZone("", -4*60*60),
+			want: "2023-02-15 14:02:12.321 -04:00",
+		},
+		{
+			in:   "2024-02-29 02:01:12 -06:00",
+			loc:  time.FixedZone("", -4*60*60),
+			want: "2024-02-29 02:01:12 -04:00",
+		},
+		{
+			in:   "2023-02-15 04:02:12.321 +02:00",
+			loc:  time.UTC,
+			want: "2023-02-15 04:02:12.321 +00:00",
+		},
+		{
+			in:   "2023-02-15 04:02:12.321 +00:00",
+			loc:  time.UTC,
+			want: "2023-02-15 04:02:12.321 +00:00",
+		},
+	}
+	for _, tt := range tests {
+		in, _ := time.Parse(defaultDateTime64FormatWithZone, tt.in)
+		got := getTimeWithDifferentLocation(in, tt.loc)
+		assert.Equal(t, tt.want, got.Format(defaultDateTime64FormatWithZone))
+	}
+}
+
+var benchmarkResultTime time.Time
+
+func BenchmarkGetTimeWithDifferentLocation(b *testing.B) {
+	t := time.Date(2023, time.April, 12, 1, 12, 33, 0, time.UTC)
+	loc := time.FixedZone("", 4*60*60)
+
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		benchmarkResultTime = getTimeWithDifferentLocation(t, loc)
+	}
+}