For UPDATE operation, row count for 'Changed: ' returned is incorrect

engine: 1e56a0b557efb677d07533d05eb02ad723955317
server: 11c83d9ae9eb249d00589cc6ab71e7f4e67ffa27
buildNo: 7534

For UPDATE, the "Changed: " row count is always the same as "Rows matched". For InnoDB tables, "Changed: " reflects only the actual rows changed.

ColumnStore

MariaDB [mytest]> create table t2 (c1 int, c2 int) engine=columnstore;

Query OK, 0 rows affected (0.125 sec)

MariaDB [mytest]> insert into t2 values (1,1),(1,1),(1,1);

Query OK, 3 rows affected (0.106 sec)

Records: 3  Duplicates: 0  Warnings: 0

MariaDB [mytest]> select * from t2;

+------+------+

| c1   | c2   |

+------+------+

|    1 |    1 |

|    1 |    1 |

|    1 |    1 |

+------+------+

3 rows in set (0.050 sec)

MariaDB [mytest]> update t2 set c1=1;

Query OK, 3 rows affected (0.090 sec)

Rows matched: 3  Changed: 3  Warnings: 0

MariaDB [mytest]> insert t2 values (2,2);

Query OK, 1 row affected (0.092 sec)

MariaDB [mytest]> select * from t2;

+------+------+

| c1   | c2   |

+------+------+

|    1 |    1 |

|    1 |    1 |

|    1 |    1 |

|    2 |    2 |

+------+------+

4 rows in set (0.014 sec)

MariaDB [mytest]> update t2 set c1=2;

Query OK, 4 rows affected (0.098 sec)

Rows matched: 4  Changed: 4  Warnings: 0

InnoDB

MariaDB [mytest]> create table t1 (c1 int, c2 int) engine=innodb;
Query OK, 0 rows affected (0.013 sec)

MariaDB [mytest]> insert into t1 values (1,1),(1,1),(1,1);
Query OK, 3 rows affected (0.003 sec)
Records: 3 Duplicates: 0 Warnings: 0

MariaDB [mytest]> select * from t1;
----------+

----------+

----------+
3 rows in set (0.001 sec)

MariaDB [mytest]> update t1 set c1=1;
Query OK, 0 rows affected (0.001 sec)
Rows matched: 3 Changed: 0 Warnings: 0

MariaDB [mytest]> insert t1 values (2,2);
Query OK, 1 row affected (0.003 sec)

MariaDB [mytest]> select * from t1;
----------+

----------+

----------+
4 rows in set (0.001 sec)

MariaDB [mytest]> update t1 set c1=2;
Query OK, 3 rows affected (0.002 sec)
Rows matched: 4 Changed: 3 Warnings: 0