enable_partition_pruning — PostgreSQL configuration parameter

Enables or disables the query planner’s ability to eliminate a partitioned table’s partitions from query plans.

At a glance

What it does

Enables or disables the query planner’s ability to eliminate a partitioned table’s partitions from query plans. This also controls the planner’s ability to generate query plans which allow the query executor to remove (ignore) partitions during query execution. The default is on. See ddl_partition_pruning for details.

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

Tuning guidance

This is a diagnostic switch, not a production tuning knob. Turn it off briefly (per session) to confirm why the planner avoids or prefers a plan, then leave it on. Forcing it off in production masks bad estimates instead of fixing them — fix statistics, costs or indexes instead.

Reference

PostgreSQL documentation — enable_partition_pruning.