Specifies the maximum number of updated or deleted tuples needed to trigger a VACUUM in any one table, i.e., a limit on the value calculated with autovacuum_vacuum_threshold and autovacuum_vacuum_scale_factor.
At a glance
| Property | Value |
|---|---|
| Parameter | autovacuum_vacuum_max_threshold |
| Category | Vacuuming |
| Default | 100,000,000 |
| Value type | integer |
| Change scope | Reload (postgresql.conf, SIGHUP) |
| Available in | PostgreSQL 18, 19 (added in 18) |
What it does
Specifies the maximum number of updated or deleted tuples needed to trigger a VACUUM in any one table, i.e., a limit on the value calculated with autovacuum_vacuum_threshold and autovacuum_vacuum_scale_factor. The default is 100,000,000 tuples. If -1 is specified, autovacuum will not enforce a maximum number of updated or deleted tuples that will trigger a VACUUM operation. This parameter can only be set in the postgresql.conf file or on the server command line; but the setting can be overridden for individual tables by changing storage parameters.
(Description quoted from the official PostgreSQL documentation.)
How to apply a change
Set it in postgresql.conf (or with ALTER SYSTEM) and reload with SELECT pg_reload_conf(); or pg_ctl reload — no restart needed.
Inspect the current value and source with SHOW autovacuum_vacuum_max_threshold; or SELECT name, setting, unit, context, source FROM pg_settings WHERE name = 'autovacuum_vacuum_max_threshold';.
Tuning guidance
This parameter is rarely a performance lever. Leave it at the default unless you have a specific, documented reason to change it, change it on one session or one role/database first, and confirm the effect with pg_settings and your own measurements before rolling it out cluster-wide.