Thanks Tom! Reducing random_page_cost to 2 did the trick for this query. It now favors the index scan. Even if this is a cached situation, I wouldn't expect a difference of 3 min vs 3 seconds. Even if unrelated, do you think disk fragmentation would have negative effects? Is it worth trying to defragment the drive on a regular basis in Windows? Jeremy Haile On Tue, 16 Jan 2007 16:39:07 -0500, "Tom Lane" <tgl@xxxxxxxxxxxxx> said: > "Jeremy Haile" <jhaile@xxxxxxxxxxx> writes: > > Running PostgreSQL 8.2.1 on Win32. The query planner is choosing a seq > > scan over index scan even though index scan is faster (as shown by > > disabling seqscan). Table is recently analyzed and row count estimates > > seem to be in the ballpark. > > Try reducing random_page_cost a bit. Keep in mind that you are probably > measuring a fully-cached situation here, if you repeated the test case. > If your database fits into memory reasonably well then that's fine and > you want to optimize for that case ... but otherwise you may find > yourself pessimizing the actual behavior. > > regards, tom lane
