[#MDEV-9855] log_slave_updates is required for wsrep_gtid

When wsrep_gtid_mode is ON, transactions replicated via Galera Cluster's replication should increment the GTID in the domain given by wsrep_gtid_domain_id on all nodes. This only seems to happen on all nodes if log_slave_updates is enabled.

For example, let's say that we have a 2-node Galera Cluster:

Node 1:

MariaDB [(none)]> SHOW GLOBAL VARIABLES LIKE 'wsrep_gtid%';

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

| Variable_name        | Value |

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

| wsrep_gtid_domain_id | 3     |

| wsrep_gtid_mode      | ON    |

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

2 rows in set (0.00 sec)

MariaDB [(none)]> SHOW GLOBAL VARIABLES LIKE 'log_slave_updates';

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

| Variable_name     | Value |

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

| log_slave_updates | OFF   |

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

1 row in set (0.00 sec)

MariaDB [(none)]> SHOW GLOBAL VARIABLES LIKE 'gtid%pos';

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

| Variable_name    | Value                 |

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

| gtid_binlog_pos  | 0-1-5,1-1-63334,3-1-9 |

| gtid_current_pos | 0-1-5,1-1-63334,3-1-9 |

| gtid_slave_pos   |                       |

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

3 rows in set (0.00 sec)

Node 2:

MariaDB [(none)]> SHOW GLOBAL VARIABLES LIKE 'wsrep_gtid%';

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

| Variable_name        | Value |

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

| wsrep_gtid_domain_id | 3     |

| wsrep_gtid_mode      | ON    |

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

2 rows in set (0.01 sec)

MariaDB [(none)]> SHOW GLOBAL VARIABLES LIKE 'log_slave_updates';

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

| Variable_name     | Value |

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

| log_slave_updates | OFF   |

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

1 row in set (0.00 sec)

MariaDB [(none)]> SHOW GLOBAL VARIABLES LIKE 'gtid%pos';

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

| Variable_name    | Value                 |

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

| gtid_binlog_pos  | 0-1-5,1-1-63334,3-1-9 |

| gtid_current_pos |                       |

| gtid_slave_pos   |                       |

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

3 rows in set (0.00 sec)

Now let's see how gtid_binlog_pos changes on each node.

Node 1:

MariaDB [(none)]> SHOW GLOBAL VARIABLES LIKE 'gtid%pos';

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

| Variable_name    | Value                  |

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

| gtid_binlog_pos  | 0-1-5,1-1-63334,3-1-10 |

| gtid_current_pos | 0-1-5,1-1-63334,3-1-10 |

| gtid_slave_pos   |                        |

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

3 rows in set (0.00 sec)

Node 2:

MariaDB [(none)]> SHOW GLOBAL VARIABLES LIKE 'gtid%pos';

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

| Variable_name    | Value                 |

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

| gtid_binlog_pos  | 0-1-5,1-1-63334,3-1-9 |

| gtid_current_pos |                       |

| gtid_slave_pos   |                       |

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

3 rows in set (0.00 sec)

MariaDB [(none)]> select * from db1.tab1;

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

| id | str  |

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

|  1 | str1 |

|  2 | str2 |

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

2 rows in set (0.00 sec)

Let's try again with log_slave_updates enabled.

Node 1:

MariaDB [(none)]> SHOW GLOBAL VARIABLES LIKE 'wsrep_gtid%';

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

| Variable_name        | Value |

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

| wsrep_gtid_domain_id | 3     |

| wsrep_gtid_mode      | ON    |

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

2 rows in set (0.00 sec)

MariaDB [(none)]> SHOW GLOBAL VARIABLES LIKE 'log_slave_updates';

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

| Variable_name     | Value |

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

| log_slave_updates | ON    |

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

1 row in set (0.00 sec)

MariaDB [(none)]> SHOW GLOBAL VARIABLES LIKE 'gtid%pos';

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

| Variable_name    | Value                  |

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

| gtid_binlog_pos  | 0-1-5,1-1-63334,3-1-10 |

| gtid_current_pos | 0-1-5,1-1-63334,3-1-10 |

| gtid_slave_pos   |                        |

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

3 rows in set (0.00 sec)

MariaDB [(none)]> insert into db1.tab1 values (3, 'str3');

Query OK, 1 row affected (0.01 sec)

MariaDB [(none)]> SHOW GLOBAL VARIABLES LIKE 'gtid%pos';

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

| Variable_name    | Value                  |

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

| gtid_binlog_pos  | 0-1-5,1-1-63334,3-1-11 |

| gtid_current_pos | 0-1-5,1-1-63334,3-1-11 |

| gtid_slave_pos   |                        |

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

3 rows in set (0.00 sec)

Node 2:

MariaDB [(none)]> SHOW GLOBAL VARIABLES LIKE 'gtid%pos';

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

| Variable_name    | Value                  |

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

| gtid_binlog_pos  | 0-1-5,1-1-63334,3-1-11 |

| gtid_current_pos |                        |

| gtid_slave_pos   |                        |

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

3 rows in set (0.00 sec)

MariaDB [(none)]> select * from db1.tab1;

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

| id | str  |

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

|  1 | str1 |

|  2 | str2 |

|  3 | str3 |

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

3 rows in set (0.00 sec)

[MDEV-9855] log_slave_updates is required for wsrep_gtid_mode Created: 2016-03-31 Updated: 2019-05-23 Resolved: 2019-05-23
Status:	Closed
Project:	MariaDB Server
Component/s:	Galera, Replication
Affects Version/s:	10.1.13
Fix Version/s:	N/A

[MDEV-9855] log_slave_updates is required for wsrep_gtid_mode Created: 2016-03-31 Updated: 2019-05-23 Resolved: 2019-05-23