Transaction ID wraparound forces emergency autovacuum despite disabled autovacuum

When a table's pg_class.relfrozenxid age reaches autovacuum_freeze_max_age (default 200 million transactions), the system launches autovacuum processes to prevent transaction ID wraparound even when autovacuum is otherwise disabled. This forced vacuum can cause unexpected load spikes.

Monitor database_wraparound_age_datfrozenxid metric to track proximity to wraparound threshold. If approaching limit, manually run VACUUM FREEZE on large tables during maintenance windows. Consider reducing autovacuum_freeze_max_age for individual large tables via table storage parameters to spread vacuum load. Enable autovacuum globally to prevent emergency situations.