LQO runs each of your queries under PostgreSQL's default plan and under a set of planner settings, on a replica, and tells you which settings make which queries clearly faster. One binary, no extension, nothing changed on your server.
−36%
Time for the demo's trap query with the setting LQO found, 1,061 ms down to 684 ms
0 writes
Got through in tests that send writes past LQO's own checks. Every trial is read-only and rolled back
1 binary
No dependencies and no extension. PostgreSQL 14 to 18
Apache 2.0
License for all of the code
Measured on a two-core cloud machine with PostgreSQL 16. The test logs are on GitHub.
releases
Every PostgreSQL database has a few queries the planner gets badly wrong. Not slow because they’re big. Slow because the planner guessed the wrong row count, picked …
benchmarks
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 …
testing
A tool that runs your queries on a database has two jobs, and the first one matters more. It must never do harm: no writes, no settings left behind, no runaway query. …
guides
A query optimizer turns your SQL into a plan: which table to read first, which index to use, how to join one table to the next. A learned query optimizer is one that …
the name
LQO is short for learned query optimizer, the name database researchers use for an optimizer that improves from what queries actually did rather than from its own …
If LQO nearly fits your database, or you'd like it to do something it doesn't yet, write in.