autocommit handles process issues

[keeplearning20221]

Bug Report

Please answer these questions before submitting your issue. Thanks!

1. Minimal reproduce step (Required)

set autocommit = ON;
begin;
Query OK, 0 rows affected (0.00 sec)

mysql> select * from test.t1;
+-----+
| id |
+-----+
| 590 |
+-----+
1 row in set (0.01 sec)

mysql> update test.t1 set id = id+1;
Query OK, 1 row affected (0.00 sec)
Rows matched: 1 Changed: 1 Warnings: 0

mysql> select * from test.t1;
+-----+
| id |
+-----+
| 591 |
+-----+
1 row in set (0.01 sec)

mysql> set autocommit = ON;
Query OK, 0 rows affected (0.01 sec)

mysql> rollback;

2. What did you expect to see? (Required)

consistent with mysql
select * from test.t1;
+-----+
| id |
+-----+
| 590 |
+-----+

3. What did you see instead (Required)

select * from test.t1;
+-----+
| id |
+-----+
| 591 |
+-----+
1 row in set (0.01 sec)

4. What is your TiDB version? (Required)

Release Version: v6.1.0
Edition: Community
Git Commit Hash: 1a89dec
Git Branch: heads/refs/tags/v6.1.0
UTC Build Time: 2022-06-05 05:15:11
GoVersion: go1.18.2
Race Enabled: false
TiKV Min Version: v3.0.0-60965b006877ca7234adaced7890d7b029ed1306
Check Table Before Drop: false |

[seiya-annie]

tested in mysql 8.0.23:

mysql> create table test(a int);
Query OK, 0 rows affected (0.05 sec)

mysql> insert into test values (590);
Query OK, 1 row affected (0.01 sec)

mysql> set autocommit = ON;
Query OK, 0 rows affected (0.01 sec)

mysql> begin;
Query OK, 0 rows affected (0.00 sec)

mysql> select * from test;
+------+
| a    |
+------+
|  590 |
+------+
1 row in set (0.00 sec)

mysql> update test set a= a+1;
Query OK, 1 row affected (0.00 sec)
Rows matched: 1  Changed: 1  Warnings: 0

mysql> select * from test;
+------+
| a    |
+------+
|  591 |
+------+
1 row in set (0.00 sec)

mysql> set autocommit = ON;
Query OK, 0 rows affected (0.00 sec)

mysql> rollback;
Query OK, 0 rows affected (0.01 sec)

mysql> select * from test;
+------+
| a    |
+------+
|  590 |
+------+
1 row in set (0.00 sec)

mysql> exit

[seiya-annie]

tried on 4.0.16, exists the same issue

[cfzjywxk]

@seiya-annie
Thanks for the analysis, it's needed to be fixed.