Receiving the following error when saving changes to any pages:
A database query error has occurred. This may indicate a bug in the software.
Query:
COMMIT
Function: LoadBalancer::commitMasterChanges
Error: 1213 Deadlock found when trying to get lock; try restarting transaction (URL of MariaDB/MySQL Read/Write cluster)
MariaDB Galera Server 5.5.44 in a 3 node cluster using MariaDB Maxscale as load balancer/read&write proxy
What is $wgMainCacheType set to? Have you looked at SHOW INNODB STATUS to see the last deadlock?
I don't see why this should always happen, though in any case it might help to initiate writes only on some preferred master rather than all of them.
$wgMainCacheType = CACHE_NONE; $wgMemCachedServers = array();
The cluster is currently configured to only write to one host as we were having issues with another application being in multimaster mode.
SHOW INNODB STATUS isn't an accepted command in MariaDB Galera. Correct syntax: SHOW ENGINE INNODB STATUS;
Last captured deadlock has nothing to do with this MediaWiki error.
Closing as an old report with no further reports from other users since. Please re-open if this is still an issue on a currently supported version of MediaWiki.