Galera Write-Set Certification Failures
warningGalera cluster transactions failing certification due to conflicts detected during optimistic locking. High certification failure rate indicates concurrent writes to same data across nodes, reducing effective write throughput and causing application-level errors.
mysql.galera.wsrep_local_cert_failures rate > 5/sec, with mysql.galera.wsrep_received and mysql.galera.wsrep_replicated_bytes showing high replication traffic
Certification failures in Galera are normal but high rates indicate suboptimal write distribution. Review application write patterns: 1) Use application-level write routing to direct related writes to same node, 2) Implement retry logic for certification failures (error 1213 deadlock), 3) Batch related updates in single transaction to reduce conflict window. Check transaction isolation level - READ-COMMITTED has fewer conflicts than REPEATABLE-READ. Monitor mysql.galera.wsrep_cert_deps_distance - higher distance allows more parallelization. Consider node-specific write domains if possible to minimize cross-node conflicts.