vacuum_freeze_min_age

vacuum_freeze_min_age — Minimum age at which VACUUM should freeze a table row. Observed in PG9.0–19 Beta 3; its last measured boot default is 50000000 in PG19 Beta 3, with user context. This is a beta-snapshot fact and can change before PostgreSQL 19 GA.

Note

Fact — official short description: “Minimum age at which VACUUM should freeze a table row.”

Identity

Type , Valueinteger: Upstream pg_settings type
Context , Valueuser: Settable by an ordinary user
Unit , Value—: Raw unit
Range , Value0 – 1000000000: Raw limits in the last observed version
Enum values , Value—: — for non-enum types
Category , ValueVacuuming / Freezing: Upstream classification
Latest boot value , Value50000000: 50000000

Lifecycle

Fact	Value
First observed	PG9.0 (research boundary)
Present in	PG9.0–19 Beta 3
Removed in	No
Introduction commit	Not asserted: predates the PG9.0 research boundary
Commit date	—
Discussion	—

Default history

Measured PG9.0–19 Beta 3 boot defaults
Versions	Raw `boot_val`	Unit	Human value
PG9.0–19 Beta 3	`50000000`	—	50000000

How it works

Sets the minimum XID age at which VACUUM freezes tuple xmin values. It is a user-context setting, so a session can override it for manual VACUUM.

VACUUM computes an XID freeze cutoff from this age. Lower values freeze XIDs earlier and can repeat work on rows soon updated; higher values defer work. The effective value is capped at half of autovacuum_freeze_max_age.

Track age(relfrozenxid) for tables and age(datfrozenxid) for every database. Interpret this lower cutoff with vacuum_freeze_table_age, autovacuum_freeze_max_age, and vacuum_failsafe_age; the separate vacuum_multixact_freeze_min_age controls MXIDs.

Tuning advice

Tip

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

Workload	Guidance
OLTP	Keep enough distance below autovacuum_freeze_max_age for routine vacuums to advance relfrozenxid. Tune from peak XID consumption and measured vacuum completion, not days on a calendar.
OLAP	For append-mostly or static partitions, a lower value during planned VACUUM can freeze XIDs earlier and reduce later aggressive work; verify the extra WAL and scan cost.
Small nodes	Keep the upstream default unless XID-age evidence justifies a change. Small databases still share the cluster transaction counter and need every database monitored.

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: PG9.0–19 Beta 3 unmodified; OLAP: PG9.0–19 Beta 3 unmodified; CRIT: PG9.0–19 Beta 3 unmodified; TINY: PG9.0–19 Beta 3 unmodified. No Pigsty-specific rationale is inferred from an absent override.

Common pitfalls

Describing the cutoff as an MXID control; MultiXacts use vacuum_multixact_freeze_min_age.
Converting XID age to time without the measured transaction rate.
Raising the value so far that routine vacuum loses useful headroom before anti-wraparound work.
Ignoring per-table autovacuum_freeze_min_age overrides.

autovacuum_freeze_max_age · vacuum_freeze_table_age · vacuum_failsafe_age · vacuum_multixact_freeze_min_age · autovacuum · log_autovacuum_min_duration