From b8d929c3c75459415bbf7ccd4ed0d4eedfc52be9 Mon Sep 17 00:00:00 2001
From: Qiaolin Yu <90088090+Qiaolin-Yu@users.noreply.github.com>
Date: Tue, 20 Sep 2022 16:48:08 +0800
Subject: [PATCH] time: fix the fraction loss when encountering time string
 with timezone suffix (#37820)

* fix the issue of fraction loss when inserting time item

* fix wrong index

* add comments

Co-authored-by: Weizhen Wang <wangweizhen@pingcap.com>
Co-authored-by: Ti Chi Robot <ti-community-prow-bot@tidb.io>
---
 types/time.go      | 10 +++++++++-
 types/time_test.go |  3 +++
 2 files changed, 12 insertions(+), 1 deletion(-)

diff --git a/types/time.go b/types/time.go
index 3d997d940ddf4..132e904d6da00 100644
--- a/types/time.go
+++ b/types/time.go
@@ -575,9 +575,17 @@ func GetFsp(s string) int {
 
 // GetFracIndex finds the last '.' for get fracStr, index = -1 means fracStr not found.
 // but for format like '2019.01.01 00:00:00', the index should be -1.
+// It will not be affected by the time zone suffix. For format like '2020-01-01 12:00:00.123456+05:00', the index should be 19.
 func GetFracIndex(s string) (index int) {
+	tzIndex, _, _, _, _ := GetTimezone(s)
+	var end int
+	if tzIndex != -1 {
+		end = tzIndex - 1
+	} else {
+		end = len(s) - 1
+	}
 	index = -1
-	for i := len(s) - 1; i >= 0; i-- {
+	for i := end; i >= 0; i-- {
 		if unicode.IsPunct(rune(s[i])) {
 			if s[i] == '.' {
 				index = i
diff --git a/types/time_test.go b/types/time_test.go
index af88a18ea1fcf..cf14ca56f8f0a 100644
--- a/types/time_test.go
+++ b/types/time_test.go
@@ -110,6 +110,9 @@ func TestDateTime(t *testing.T) {
 		{"2020-05-28 23:59:59T T00:00:00", "2020-05-28 23:59:59"},
 		{"2020-10-22 10:31-10:12", "2020-10-22 10:31:10"},
 		{"2018.01.01 01:00:00", "2018-01-01 01:00:00"},
+
+		// For issue 35291
+		{"2020-01-01 12:00:00.123456+05:00", "2020-01-01 07:00:00.123456"},
 	}
 
 	for _, test := range table {