insert two rows successfully with same primary key

[siddontang]

Bug Report

Please answer these questions before submitting your issue. Thanks!

1. What did you do?

mysql> use test;
Database changed
mysql> create table t (name varchar(256) primary key, v int);
Query OK, 0 rows affected (0.07 sec)

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

mysql> insert into t values ("a", 1), ("b", 3), ("a", 2) on duplicate key update v = v + 1;
Query OK, 4 rows affected (0.01 sec)
Records: 3  Duplicates: 1  Warnings: 0

mysql> select * from t;
+------+------+
| name | v    |
+------+------+
| a    |    2 |
| b    |    3 |
+------+------+
2 rows in set (0.00 sec)

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

mysql> select * from t;
+------+------+
| name | v    |
+------+------+
| a    |    2 |
| b    |    3 |
+------+------+
2 rows in set (0.01 sec)

mysql> insert into t values ("a", 1), ("b", 3), ("a", 2) on duplicate key update v = v + 1;
Query OK, 5 rows affected (0.00 sec)
Records: 3  Duplicates: 2  Warnings: 0

mysql> select * from t;
+------+------+
| name | v    |
+------+------+
| a    |    2 |
| b    |    4 |
| a    |    2 |
+------+------+
3 rows in set (0.00 sec)

2. What did you expect to see?

Only one row with a

3. What did you see instead?

Two rows

4. What version of TiDB are you using? (tidb-server -V or run select tidb_version(); on TiDB)

3.0.10