jit_optimize_above_cost — PostgreSQL configuration parameter

Sets the query cost above which JIT compilation applies expensive optimizations.

At a glance

What it does

Sets the query cost above which JIT compilation applies expensive optimizations. Such optimization adds planning time, but can improve execution speed. It is not meaningful to set this to less than jit_above_cost, and it is unlikely to be beneficial to set it to more than jit_inline_above_cost. Setting this to -1 disables expensive optimizations. The default is 500000.

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

Tuning guidance

Raise it to skip the LLVM optimization pass on queries too short to amortize it; -1 disables optimization. It only matters when JIT is enabled and triggered.

Reference

PostgreSQL documentation — jit_optimize_above_cost.