On Tue, 2006-05-30 at 11:05 -0400, Tom Lane wrote: > Do you have realistic test data? The EXPLAIN shows that this is pulling > 275366 of the 826032 rows in the two tables, which seems like rather a > lot for a single user. If it's reasonable that the query needs to fetch > one-third of the data, then you should resign yourself to it taking > awhile :-( I'd say so, yes. The user_subscription table now has only six rows, but the number of actions (giving/taking credits) for a user could easily be as high as 50.000. > If the expected number of matching rows were much smaller, it would > make sense to use indexscans over the two big tables, but unfortunately > existing PG releases don't know how to generate an indexscan join > with a UNION ALL in between :-(. FWIW, 8.2 will be able to do it. > In current releases the only thing I can suggest is to merge > user_subscription_credits_given and user_subscription_credits_taken > into one table so you don't need the UNION ALL. See, that's an idea! :) Thnx, I'll try that. Is it inapropriate to ask about rough estimate on availableness of 8.2? :) Mario -- Mario Splivalo Mob-Art mario.splivalo@xxxxxxxxx "I can do it quick, I can do it cheap, I can do it well. Pick any two."
