Sets the planner’s estimate of the cost of processing each operator or function executed during a query.
At a glance
| Property | Value |
|---|---|
| Parameter | cpu_operator_cost |
| Category | Query Planning |
| Default | 0.0025 |
| Value type | floating point |
| Change scope | Per-session (SET) |
| Available in | PostgreSQL 12, 13, 14, 15, 16, 17, 18, 19 (added in 12) |
What it does
Sets the planner’s estimate of the cost of processing each operator or function executed during a query. The default is 0.0025.
(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 cpu_operator_cost; or SELECT name, setting, unit, context, source FROM pg_settings WHERE name = 'cpu_operator_cost';.
Tuning guidance
Increase it when the planner over-favours plans with many quals/expressions evaluated per row (complex filters or hash conditions). Small, coordinated changes to the cpu_* trio move many plans at once, so test on representative queries.