Public bug reported: When running OpenStack against Percona XtraDB 5.6 (Xenial) we observe foreign key violation crashes on the slave servers when using wsrep_slave_threads > 1. This happens semi-regularly every few days in at least 1 production environment.
Unfortunately it is not straight forward to reproduce in a test environment and likely requires a fairly performant test environment to reproduce the race. It was done many times in production particularly when deploying large heat templates against an OpenStack cloud but do not currently have a test case or even precise OpenStack steps to reproduce the issue. I suggest we can try using rally or otherwise concuct some heat templates to reproduce the issue. The servers in question were also running on HDD storage. I did find the following similar bug though without a lot of detail: https://jira.mariadb.org/browse/MDEV-13246 2018-10-08 02:26:11 283550 [ERROR] Slave SQL: Could not execute Delete_rows event on table heat.raw_template; Cannot delete or update a parent row: a foreign key constraint fails (`heat`.`stack`, CONSTRAINT `stack_ibfk_2` FOREIGN KEY (`prev_raw_template_id`) REFERENCES `raw_template` (`id`)), Error_code: 1451; handler error HA_ERR_ROW_IS_REFERENCED; the event's master log FIRST, end_log_pos 12099, Error_code: 1451 2018-10-08 02:26:11 283550 [Warning] WSREP: RBR event 3 Delete_rows apply warning: 152, 90837000 2018-10-08 02:26:11 283550 [Warning] WSREP: Failed to apply app buffer: seqno: 90837000, status: 1 at galera/src/trx_handle.cpp:apply():351 Retrying 2th time ** Affects: percona-xtradb-cluster-5.6 (Ubuntu) Importance: Undecided Status: New -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1823850 Title: wsrep_slave_threads >1 causes foreign key constraint violations To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/percona-xtradb-cluster-5.6/+bug/1823850/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
