Parameter · Vacuuming / Freezing
vacuum_multixact_failsafe_age
Multixact age at which VACUUM should trigger failsafe to avoid a wraparound outage.
- Default:
1600000000 - Type: integer
- Range: 0 … 2100000000
- Applies: Session (any user)
In plain words
The MultiXact version of the vacuum failsafe (PostgreSQL 14+). If a table's MultiXact age passes 1.6 billion, VACUUM stops sleeping and skips non-essential work so it can freeze as fast as possible.
For DBAs and operators
Never effectively lower than 105% of autovacuum_multixact_freeze_max_age. Same behaviour and same log line as vacuum_failsafe_age: WARNING: bypassing nonessential maintenance of table "app.public.orders" as a failsafe after 0 index scans. If you reach it, find what blocks freezing (old transactions holding MultiXacts, prepared transactions) and check pg_multixact size.
How to change it
Any user can change it for their session with SET.