LQO Finds Faster PostgreSQL Plans for 35 of 94 Join Order Benchmark Query Shapes

Mon, 19 Oct 2026 00:00:00 +0000

The Join Order Benchmark is where query optimizers go to be embarrassed. It’s 113 queries over the IMDB movie database, real data with all its skew and correlated columns, and it was built to show how far a planner’s row estimates can drift from the truth. If a tool claims to find better plans, this is the first place anyone should look.

So LQO 0.1.0 ran it, start to finish, on a GitHub runner: 4 cores, 15 GB of memory, PostgreSQL 16 with 5 GB of shared buffers. The 113 queries fold into 94 query shapes, because some JOB variants differ only in their constants. Each shape ran under the default plan and under LQO’s 13 standard hints, with a warm-up run and three timed runs per plan. The whole thing took 75 minutes.

Benchmarks on lqo.net

LQO Finds Faster PostgreSQL Plans for 35 of 94 Join Order Benchmark Query Shapes