Throttling pause for autovacuum I/O.
At a glance
| Property | Value |
|---|---|
| Parameter | autovacuum_vacuum_cost_delay |
| Category | Autovacuum |
| Default | 2ms |
| Value type | time (ms/s/min) |
| Change scope | Reload (no restart) |
What it does
The sleep autovacuum takes after accumulating autovacuum_vacuum_cost_limit cost, throttling its I/O impact. Default lowered to 2ms in PG12.
How to apply a change
Takes effect on configuration reload (sighup context). Run SELECT pg_reload_conf(); or send SIGHUP — no restart needed.
Inspect the current value and source with SHOW autovacuum_vacuum_cost_delay; or SELECT name, setting, unit, context, source FROM pg_settings WHERE name = 'autovacuum_vacuum_cost_delay';.
Tuning guidance
Lower to 0-1ms (or raise the cost limit) to let autovacuum keep up on fast storage; the conservative default can let busy tables outrun the cleaner.