vacuum_cost_limit — PostgreSQL configuration parameter

This is the accumulated cost that will cause the vacuuming process to sleep for vacuum_cost_delay.

At a glance

What it does

This is the accumulated cost that will cause the vacuuming process to sleep for vacuum_cost_delay. The default is 200.

(Description quoted from the official PostgreSQL documentation.)

How to apply a change

Can be set per session with SET, per role/database with ALTER ROLE/DATABASE ... SET, or globally in postgresql.conf.

Inspect the current value and source with SHOW vacuum_cost_limit; or SELECT name, setting, unit, context, source FROM pg_settings WHERE name = 'vacuum_cost_limit';.

Tuning guidance

Raise it to let vacuum do more work between sleeps (faster, more I/O); the autovacuum equivalent is autovacuum_vacuum_cost_limit. Pair changes with vacuum_cost_delay.

Reference

PostgreSQL documentation — vacuum_cost_limit.