vacuum_failsafe_age

vacuum_failsafe_age sets the age at which VACUUM should trigger failsafe to avoid a wraparound outage. It is a user setting present in PG14–18; the latest recorded boot default is 1600000000.

Note

Fact — official short description: “Age at which VACUUM should trigger failsafe to avoid a wraparound outage.”

Identity

Type , Valueinteger: Upstream pg_settings type
Context , Valueuser: Settable by an ordinary user
Unit , Value—: Raw unit
Range , Value0 – 2100000000: Raw limits in the last observed version
Enum values , Value—: — for non-enum types
Category , ValueVacuuming / Freezing: Upstream classification
Latest boot value , Value1600000000: 1600000000

Lifecycle

Fact	Value
First observed	PG14
Present in	PG14–19 Beta 3
Removed in	No
Introduction commit	`1e55e7d1755c` — Add wraparound failsafe to VACUUM.
Commit date	2021-04-07
Discussion	thread 1 · thread 2

Default history

Measured PG9.0–19 Beta 3 boot defaults
Versions	Raw `boot_val`	Unit	Human value
PG14–19 Beta 3	`1600000000`	—	1600000000

How it works

Age at which VACUUM should trigger failsafe to avoid a wraparound outage. It can be changed at session scope, so different sessions may observe different behavior.

At the failsafe age, a running VACUUM prioritizes advancing the freeze horizon quickly: cost delays stop and optional work such as index cleanup and tail truncation is skipped. This is a last defense against wraparound outage, not a routine performance mode.

Monitor and change vacuum_failsafe_age together with autovacuum_freeze_max_age, vacuum_freeze_min_age, vacuum_freeze_table_age. Validate on the relevant server role and real workload, then use its user context to choose session change, reload, or restart; a historical boot default is not the current effective value.

Tuning advice

Tip

Advice. These are workload-specific starting points and must be validated with measurements.

Workload	Guidance
OLTP	Calibrate vacuum_failsafe_age against the oldest XID/MXID age in every database and measured vacuum completion rate. Remove long transactions, stale slots, and blocked workers; never raise ages merely to hide a backlog.
OLAP	Proactively VACUUM (FREEZE) newly loaded or static partitions in batch windows and reserve I/O time for full scans. Convert age budgets using peak transaction rate, not a wall-clock guess.
Small nodes	Upstream defaults are usually safest. A small system still needs anti-wraparound maintenance; monitor every database, not only the application database.

Pigsty

Values use the fixed 8-vCPU, 32-GiB, 100-GiB SSD fixture and render the current Pigsty templates for PG19 Beta 3; this does not assert current Pigsty support for that historical or beta release.

Template	Effective value	Versus upstream boot	Source expression
OLTP	Unmodified	—	—
OLAP	Unmodified	—	—
CRIT	Unmodified	—	—
TINY	Unmodified	—	—

Caution

Advice — pending human review. Fact from the current Pigsty template projection: OLTP: PG14–19 Beta 3 unmodified; OLAP: PG14–19 Beta 3 unmodified; CRIT: PG14–19 Beta 3 unmodified; TINY: PG14–19 Beta 3 unmodified. No Pigsty-specific rationale is inferred from an absent override.

Common pitfalls

Treating failsafe as a normal high-throughput VACUUM mode.
Ignoring skipped index cleanup after the emergency has passed.
Raising the age to suppress evidence of a maintenance failure.
Changing the global value while a table storage parameter overrides it.
Treating reltuples and cumulative change statistics as exact real-time counts.

autovacuum_freeze_max_age · vacuum_freeze_min_age · vacuum_freeze_table_age · autovacuum_multixact_freeze_max_age · vacuum_multixact_freeze_min_age · vacuum_multixact_freeze_table_age