4 ms·
You're probably right, I was just throwing it out there; some kind of heuristic search algorithm, anyway. Postgres actually uses GAs for complex plans [1]. Bec
by lobster_johnson 13y ago
You're probably right, I was just throwing it out there; some kind of heuristic search algorithm, anyway.
Postgres actually uses GAs for complex plans [1]. Because it's slower than the normal cost-based planner, it only kicks in when a query involves 12 or more tables.
[1] http://www.postgresql.org/docs/9.1/static/geqo.html http://www.postgresql.org/docs/9.1/static/geqo.html
- jacques_chester 13y agoFascinating. Is it actually enabled by default or is a module that needs to be activated? The docco is a bit unclear. Nature-inspired computing does tend to begin shwoing up when very large search spaces appear.
- lobster_johnson 13y agoIt's enabled by default. You can set the threshold to something other than 12 if you want to: http://www.postgresql.org/docs/9.1/static/runtime-config-query.html#RUNTIME-CONFIG-QUERY-GEQO http://www.postgresql.org/docs/9.1/static/runtime-config-que...
- jacques_chester 13y agoThanks. The coolest thing I've been wrong about in ages.