vacuum_cost_page_miss — PostgreSQL configuration parameter

The estimated cost for vacuuming a buffer that has to be read from disk.

At a glance

What it does

The estimated cost for vacuuming a buffer that has to be read from disk. This represents the effort to lock the buffer pool, lookup the shared hash table, read the desired block in from the disk and scan its content. The default value is 2.

(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_page_miss; or SELECT name, setting, unit, context, source FROM pg_settings WHERE name = 'vacuum_cost_page_miss';.

Tuning guidance

Cost charged for a buffer miss during vacuum; tune the headline vacuum_cost_delay/vacuum_cost_limit first — the per-page costs rarely need adjusting.

Reference

PostgreSQL documentation — vacuum_cost_page_miss.