# WSREP: cluster conflict due to certification failure **URL:** \ **Category:** Percona Server for MySQL 5.7\ **Tags:** mysql, percona\ **Created:** [October 31, 2020, 6:07pm UTC](https://forums.percona.com/t/wsrep-cluster-conflict-due-to-certification-failure/8218 "2020-10-31T18:07:32Z")\ **Posts on this page:** 2\ **Page:** 1
**Author:** ![random\_dev](https://avatars.discourse-cdn.com/v4/letter/r/47e85d/32.png) [@random\_dev](https://forums.percona.com/u/random_dev)\ **Post date:** [October 31, 2020, 6:07pm UTC](https://forums.percona.com/t/wsrep-cluster-conflict-due-to-certification-failure/8218/1 "2020-10-31T18:07:32Z")
Hi! I cannot understand why I’m getting errors “WSREP: cluster conflict due to certification failure”. Hope someone can help me with it because I’m literally at my wits’ end. There are 4 nodes in two datacenters, 200 RPM at max for tbl1 and 250 RPM at max for tbl2 (seems not too big). There is some system info: ```auto mysql> SELECT @@version,@@version_comment; +------------------+-------------------------------------------------------------------------------------------------+ | @@version | @@version_comment | +------------------+-------------------------------------------------------------------------------------------------+ | 5.7.27-30-57-log | Percona XtraDB Cluster (GPL), Release rel30, Revision 64987d4, WSREP version 31.39, wsrep_31.39 | +------------------+-------------------------------------------------------------------------------------------------+ 1 row in set (0.00 sec) mysql> SHOW STATUS LIKE 'wsrep_provider_version'; +------------------------+----------------+ | Variable_name | Value | +------------------------+----------------+ | wsrep_provider_version | 3.39(rb3295e6) | +------------------------+----------------+ 1 row in set (0.00 sec) mysql> SHOW VARIABLES LIKE '%auto_increment%'; +------------------------------+-------+ | Variable_name | Value | +------------------------------+-------+ | auto_increment_increment | 4 | | auto_increment_offset | 3 | | wsrep_auto_increment_control | ON | +------------------------------+-------+ 3 rows in set (0.00 sec) ``` Log example: ```auto 2020-10-24T16:47:47.100389Z 2015474331 [Note] WSREP: --------- CONFLICT DETECTED -------- 2020-10-24T16:47:47.100414Z 2015474331 [Note] WSREP: cluster conflict due to certification failure for threads: 2020-10-24T16:47:47.100421Z 2015474331 [Note] WSREP: Victim thread: THD: 2015474331, mode: local, state: executing, conflict: cert failure, seqno: 200651974 SQL: INSERT INTO tbl1 (some_varchar_field, another_varchar_field, some_foreign_key_id, some_datetime_field, another_datetime_field) VALUES (some_varchar_value, another_varchar_value, some_foreign_key_id_value, some_datetime_value, another_datetime_value) 2020-10-24T16:47:47.100437Z 2034527141 [Note] WSREP: --------- CONFLICT DETECTED -------- 2020-10-24T16:47:47.100446Z 2030700502 [Note] WSREP: --------- CONFLICT DETECTED -------- 2020-10-24T16:47:47.100453Z 2034527141 [Note] WSREP: cluster conflict due to certification failure for threads: 2020-10-24T16:47:47.100461Z 2030700502 [Note] WSREP: cluster conflict due to certification failure for threads: 2020-10-24T16:47:47.100466Z 2034527141 [Note] WSREP: Victim thread: THD: 2034527141, mode: local, state: executing, conflict: cert failure, seqno: 200651977 SQL: INSERT INTO tbl1 (some_varchar_field, another_varchar_field, some_foreign_key_id, some_datetime_field, another_datetime_field) VALUES (some_varchar_value, another_varchar_value, some_foreign_key_id_value, some_datetime_value, another_datetime_value) 2020-10-24T16:47:47.100470Z 2030700502 [Note] WSREP: Victim thread: THD: 2030700502, mode: local, state: executing, conflict: cert failure, seqno: 200651978 SQL: INSERT INTO tbl2 (some_foreign_key_id, another_foreign_key_id, one_more_foreign_key_id, some_varchar_field) VALUES (some_foreign_key_value, another_foreign_key_value, one_more_foreign_key_value, some_varchar_value) ``` tbl1 and tbl2 are not connected in any way, they correspond to different databases. What can lead to these errors? How can I identify the cause? ---
**Author:** ![przemek](https://sea1.discourse-cdn.com/flex019/user_avatar/forums.percona.com/przemek/32/3_2.png) [@przemek](https://forums.percona.com/u/przemek)\ **Post date:** [November 23, 2020, 9:37am UTC](https://forums.percona.com/t/wsrep-cluster-conflict-due-to-certification-failure/8218/2 "2020-11-23T09:37:45Z")
Hi, What if you try using this variable on all nodes: wsrep\_certification\_rules=‘OPTIMIZED’ That should help for such issues related to tables having FK constraints.