autovacuum_vacuum_insert_scale_factor

autovacuum_vacuum_insert_scale_factor sets the number of tuple inserts prior to vacuum as a fraction of reltuples. It is a sighup setting present in PG13–18; the latest recorded boot default is 0.2.

Note

Fact — official short description: “Number of tuple inserts prior to vacuum as a fraction of reltuples.”

Identity

Type , Valuereal: Upstream pg_settings type
Context , Valuesighup: Takes effect after configuration reload
Unit , Value—: Raw unit
Range , Value0 – 100: Raw limits in the last observed version
Enum values , Value—: — for non-enum types
Category , ValueVacuuming / Automatic Vacuuming: Upstream classification
Latest boot value , Value0.2: 0.2

Lifecycle

Fact	Value
First observed	PG13
Present in	PG13–19 Beta 3
Removed in	No
Introduction commit	`b07642dbcd8d` — Trigger autovacuum based on number of INSERTs
Commit date	2020-03-28
Discussion	thread 1

Default history

Measured PG9.0–19 Beta 3 boot defaults
Versions	Raw `boot_val`	Unit	Human value
PG13–19 Beta 3	`0.2`	—	0.2

How it works

Number of tuple inserts prior to vacuum as a fraction of reltuples. A configuration reload applies a new value; existing work already in flight is not retroactively changed.

For insert-heavy tables the trigger is the insert threshold plus insert scale factor times reltuples times the fraction not all-frozen. Such vacuuming can advance visibility/freeze state even without dead tuples and reduce later aggressive-vacuum work.

Monitor and change autovacuum_vacuum_insert_scale_factor together with autovacuum_vacuum_threshold, autovacuum_vacuum_scale_factor, autovacuum_vacuum_max_threshold. Validate on the relevant server role and real workload, then use its sighup 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	Tune autovacuum_vacuum_insert_scale_factor from table size, change rate, and maintenance SLA, using per-table thresholds for large/hot relations. Observe trigger intervals, dead tuples, and ANALYZE/VACUUM duration.
OLAP	Run explicit ANALYZE/VACUUM after bulk loads instead of waiting only for proportional triggers; plan freezing and visibility-map advancement separately for append-only partitions.
Small nodes	Start with upstream or the measured Pigsty matrix value. Fixed thresholds dominate on small tables; after changes, confirm worker and I/O headroom.

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: PG13–19 Beta 3 unmodified; OLAP: PG13–19 Beta 3 unmodified; CRIT: PG13–19 Beta 3 unmodified; TINY: PG13–19 Beta 3 unmodified. No Pigsty-specific rationale is inferred from an absent override.

Common pitfalls

Changing the global value while a table storage parameter overrides it.
Treating reltuples and cumulative change statistics as exact real-time counts.
Blaming a threshold without checking long transactions, replication slots, and worker saturation.
Buying short-term quiet by deferring maintenance until wraparound failsafe activates.

autovacuum_vacuum_threshold · autovacuum_vacuum_scale_factor · autovacuum_vacuum_max_threshold · autovacuum_vacuum_insert_threshold · autovacuum · autovacuum_analyze_scale_factor