Pryscila, > > There are other methods for query optimization, one of them is based on > > plan transformations (for example, using A-Star algorithm) instead of > > plan constructions used by PostgreSQL.
We do certainly need a specific optimization for large star-schema joins. I'm not certain that A* is suitable for our cost model, though; I think we might need to work up something more particular to Postgres. > > Does anyone know why this method was choosen? Are there any papers or > > researches about it? There probably are on ACM but I've not read them. Ours is a pretty straightforward implementation of a cost-based optimizer. You can always read the code ;-) Mark Kirkwood put together this nice paper on planner statistics: http://www.powerpostgresql.com/PlanStats -- Josh Berkus Aglio Database Solutions San Francisco ---------------------------(end of broadcast)--------------------------- TIP 1: if posting/reading through Usenet, please send an appropriate subscribe-nomail command to [EMAIL PROTECTED] so that your message can get through to the mailing list cleanly
