VACUUM FULL blocks production traffic during execution

VACUUM FULL requires exclusive table locks that block all read and write operations on the affected table. On production systems with continuous traffic, this causes query timeouts and service degradation for the duration of the vacuum operation, which can be hours for large tables.

Never run VACUUM FULL on production tables during business hours. Schedule during maintenance windows only. For production systems requiring continuous availability, use regular VACUUM instead and address root causes (like inactive replication slots) that prevent it from working. If VACUUM FULL is unavoidable, consider using pg_repack as a non-blocking alternative that allows concurrent reads/writes.