From 8bba5293c009db26ac32498227e2530ff9ab105e Mon Sep 17 00:00:00 2001
From: tangenta <tangenta@126.com>
Date: Sun, 8 Oct 2023 15:33:22 +0800
Subject: [PATCH] ddl: fix DST times for adding index (#47425)

ref pingcap/tidb#46033, close pingcap/tidb#47426
---
 ddl/db_test.go                 | 10 +++++-----
 ddl/index_cop.go               |  2 +-
 ddl/ingest/integration_test.go |  3 +++
 ddl/util/util.go               |  2 +-
 4 files changed, 10 insertions(+), 7 deletions(-)

diff --git a/ddl/db_test.go b/ddl/db_test.go
index 64a0442063e0f..aefcad56e751a 100644
--- a/ddl/db_test.go
+++ b/ddl/db_test.go
@@ -139,12 +139,12 @@ func TestGetTimeZone(t *testing.T) {
 		offset int
 		err    string
 	}{
-		{"set time_zone = '+00:00'", "", "UTC", 0, ""},
-		{"set time_zone = '-00:00'", "", "UTC", 0, ""},
+		{"set time_zone = '+00:00'", "", "", 0, ""},
+		{"set time_zone = '-00:00'", "", "", 0, ""},
 		{"set time_zone = 'UTC'", "UTC", "UTC", 0, ""},
-		{"set time_zone = '+05:00'", "", "UTC", 18000, ""},
-		{"set time_zone = '-08:00'", "", "UTC", -28800, ""},
-		{"set time_zone = '+08:00'", "", "UTC", 28800, ""},
+		{"set time_zone = '+05:00'", "", "", 18000, ""},
+		{"set time_zone = '-08:00'", "", "", -28800, ""},
+		{"set time_zone = '+08:00'", "", "", 28800, ""},
 		{"set time_zone = 'Asia/Shanghai'", "Asia/Shanghai", "Asia/Shanghai", 0, ""},
 		{"set time_zone = 'SYSTEM'", "Asia/Shanghai", "Asia/Shanghai", 0, ""},
 		{"set time_zone = DEFAULT", "Asia/Shanghai", "Asia/Shanghai", 0, ""},
diff --git a/ddl/index_cop.go b/ddl/index_cop.go
index d90b88cae8fd9..8098855cb79ef 100644
--- a/ddl/index_cop.go
+++ b/ddl/index_cop.go
@@ -482,7 +482,7 @@ func getRestoreData(tblInfo *model.TableInfo, targetIdx, pkIdx *model.IndexInfo,
 
 func buildDAGPB(sCtx sessionctx.Context, tblInfo *model.TableInfo, colInfos []*model.ColumnInfo) (*tipb.DAGRequest, error) {
 	dagReq := &tipb.DAGRequest{}
-	_, dagReq.TimeZoneOffset = timeutil.Zone(sCtx.GetSessionVars().Location())
+	dagReq.TimeZoneName, dagReq.TimeZoneOffset = timeutil.Zone(sCtx.GetSessionVars().Location())
 	sc := sCtx.GetSessionVars().StmtCtx
 	dagReq.Flags = sc.PushDownFlags()
 	for i := range colInfos {
diff --git a/ddl/ingest/integration_test.go b/ddl/ingest/integration_test.go
index ca1871f0dcfde..8c0f22c9a3509 100644
--- a/ddl/ingest/integration_test.go
+++ b/ddl/ingest/integration_test.go
@@ -199,12 +199,15 @@ func TestAddIndexIngestTimezone(t *testing.T) {
 	tk.MustExec("SET time_zone = '-06:00';")
 	tk.MustExec("create table t (`src` varchar(48),`t` timestamp,`timezone` varchar(100));")
 	tk.MustExec("insert into t values('2000-07-29 23:15:30','2000-07-29 23:15:30','-6:00');")
+	// Test Daylight time.
+	tk.MustExec("insert into t values('1991-07-21 00:00:00','1991-07-21 00:00:00','-6:00');")
 	tk.MustExec("alter table t add index idx(t);")
 	tk.MustExec("admin check table t;")
 
 	tk.MustExec("alter table t drop index idx;")
 	tk.MustExec("SET time_zone = 'Asia/Shanghai';")
 	tk.MustExec("insert into t values('2000-07-29 23:15:30','2000-07-29 23:15:30', '+8:00');")
+	tk.MustExec("insert into t values('1991-07-21 00:00:00','1991-07-21 00:00:00','+8:00');")
 	tk.MustExec("alter table t add index idx(t);")
 	tk.MustExec("admin check table t;")
 }
diff --git a/ddl/util/util.go b/ddl/util/util.go
index c0765e6fbe9bb..525aade903966 100644
--- a/ddl/util/util.go
+++ b/ddl/util/util.go
@@ -230,7 +230,7 @@ func GetTimeZone(sctx sessionctx.Context) (string, int) {
 		}
 	}
 	_, offset := time.Now().In(loc).Zone()
-	return "UTC", offset
+	return "", offset
 }
 
 // enableEmulatorGC means whether to enable emulator GC. The default is enable.