Improve wsrep_auto_increment_control handling

General

Escalation

General

Escalation

Description

Currently, when wsrep_auto_increment_control is ON, user can still change the auto_increment_increment and auto_increment_offset variables dynamically. Just these settings will get reset later on any cluster reconfiguration.

This may be very confusing.

When wsrep_auto_increment_control is ON, I suggest to either disable the ability of changing the auto_increment_* variables completely (return ERROR), or at least return clear WARNING message that such variable change will be discarded by any later cluster reconfiguration.

In order to not brake backwards compatibility, maybe introduce the more strict behavior (error) only if pxc_strict_mode=enforcing|master.

Quick example of current behavior:

Node1 > show variables like '%auto_inc%';
+------------------------------+-------+
| Variable_name | Value |
+------------------------------+-------+
| auto_increment_increment | 3 |
| auto_increment_offset | 3 |
| wsrep_auto_increment_control | ON |
+------------------------------+-------+
3 rows in set (0.00 sec)
Node1 > set global auto_increment_increment=1;
Query OK, 0 rows affected (0.00 sec)
Node1 > set global auto_increment_offset=1;
Query OK, 0 rows affected (0.00 sec)
Node1 > show variables like '%auto_inc%';
+------------------------------+-------+
| Variable_name | Value |
+------------------------------+-------+
| auto_increment_increment | 1 |
| auto_increment_offset | 1 |
| wsrep_auto_increment_control | ON |
+------------------------------+-------+
3 rows in set (0.00 sec)

Node1 > select @@version,@@version_comment\G
*************************** 1. row ***************************
 @@version: 5.6.39-83.1-56
@@version_comment: Percona XtraDB Cluster (GPL), Release rel83.1, Revision 0a72eda, WSREP version 26.25, wsrep_26.25
1 row in set (0.00 sec)
[root@node3 ~]# systemctl restart mysql
Node1 > show variables like '%auto_inc%';
+------------------------------+-------+
| Variable_name | Value |
+------------------------------+-------+
| auto_increment_increment | 3 |
| auto_increment_offset | 3 |
| wsrep_auto_increment_control | ON |
+------------------------------+-------+
3 rows in set (0.00 sec)

Environment

None

AFFECTED CS IDs

224754

Smart Checklist

Activity

Show:

Julia Vural March 4, 2025 at 9:27 PM

It appears that this issue is no longer being worked on, so we are closing it for housekeeping purposes. If you believe the issue still exists, please open a new ticket after confirming it's present in the latest release.