[#MDEV-31725] Change visibility of some multi

For UPDATEs involving a single table, the server call to handler::ha_direct_update_rows(ha_rows *update_rows, ha_rows *found_rows) allows ColumnStore to correctly set the number of updated rows.

However, for UPDATEs involving multi-tables, the server does not call handler::direct_update_rows(). This is causing the following UPDATE statement in ColumnStore to incorrectly report the affected number of rows to the client, even when the actual UPDATE is successful:

MariaDB [test]> CREATE TABLE mcs_1 (a INT, b INT(11), c VARCHAR(100)) engine=columnstore;

Query OK, 0 rows affected (0.287 sec)

MariaDB [test]> CREATE TABLE mcs_2 (a INT, b INT(11), c VARCHAR(100)) engine=columnstore;

Query OK, 0 rows affected (0.271 sec)

MariaDB [test]> INSERT INTO mcs_1 VALUES (33, 99, 1);

Query OK, 1 row affected (1.179 sec)

MariaDB [test]> INSERT INTO mcs_1 VALUES (33, 99, 2);

Query OK, 1 row affected (0.115 sec)

MariaDB [test]> INSERT INTO mcs_1 VALUES (33, 99, 3);

Query OK, 1 row affected (1.116 sec)

MariaDB [test]> INSERT INTO mcs_2 VALUES (33, 11, 1);

Query OK, 1 row affected (0.173 sec)

MariaDB [test]> INSERT INTO mcs_2 VALUES (33, 11, 2);

Query OK, 1 row affected (1.119 sec)

MariaDB [test]> INSERT INTO mcs_2 VALUES (33, 11, 3);

Query OK, 1 row affected (0.112 sec)

MariaDB [test]> SELECT * FROM mcs_1;

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

| a    | b    | c    |

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

|   33 |   99 | 1    |

|   33 |   99 | 2    |

|   33 |   99 | 3    |

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

3 rows in set (0.056 sec)

MariaDB [test]> UPDATE mcs_1 A, mcs_2 B SET A.b = B.b WHERE A.c = B.c LIMIT 1;

Query OK, 0 row affected (1.154 sec)

Rows matched: 0  Changed: 0  Warnings: 0

MariaDB [test]> SELECT * FROM mcs_1;

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

| a    | b    | c    |

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

|   33 |   11 | 1    |

|   33 |   99 | 2    |

|   33 |   99 | 3    |

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

3 rows in set (0.009 sec)

As can be seen, the UPDATE is successful but the number of affected rows reported to the client is incorrect.

For the above multi-table UPDATE, the server execution calls the below functions in the following order:
1. handler::rnd_init()
2. handler::rnd_end()
3. multi_update::send_eof()

multi_update::send_eof() is responsible for reporting the count of the affected rows to the client. Knowing this execution order, ColumnStore can correctly set the number of affected rows in handler::rnd_end(), provided the following members of class multi_update are made public:
multi_update::update_tables
multi_update::table_to_update
multi_update::updated
multi_update::found

[MDEV-31725] Change visibility of some multi_update members to public Created: 2023-07-17 Updated: 2023-11-28 Resolved: 2023-09-02
Status:	Closed
Project:	MariaDB Server
Component/s:	Data Manipulation - Update
Fix Version/s:	N/A

[MDEV-31725] Change visibility of some multi_update members to public Created: 2023-07-17 Updated: 2023-11-28 Resolved: 2023-09-02