(cough cough, missed the Reply to all button) Hi Jeff, On Sat, Dec 8, 2012 at 3:32 AM, Jeff Janes <jeff.janes@xxxxxxxxx> wrote: > If those estimates are better, it probably means that your filter > condition is picking a part of the "el JOIN l" that has much different > selectivity to r than the full set does, and PostgreSQL has no way of > knowing that. It's certainly that. The fact is that this query is OK on most of the French territory but it doesn't go well when you're looking at Paris area in particular. As the query is supposed to return the shows you can book, the selectivity is quite different as Paris has a lot of places AND places organize a lot more shows in Paris than in the rest of France. I was hoping that the high number of places would be enough to circumvent the second fact which is much harder for PostgreSQL to get but it looks like it's not. Is there any way I could mitigate this issue by playing with planner knobs? I don't remember having seen something I could use for selectivity (such as the n_distinct stuff). It's not that big a deal if it's a little worth elsewhere as there are far less places so the effects of a bad plan are more contained. -- Guillaume -- Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
