I am not sure what you mean by reformulate the data representation. Do you mean do I have to join on all three columns? -----Original Message----- From: Tom Lane [mailto:tgl@xxxxxxxxxxxxx] Sent: Friday, October 29, 2010 2:18 PM To: Ozer, Pam Cc: pgsql-performance@xxxxxxxxxxxxxx Subject: Re: Slow Query- Bad Row Estimate "Ozer, Pam" <pozer@xxxxxxxxxxxxxx> writes: > Unfortunately I have not received a response on this question. Is more > information needed? Does anyone have any ideas why the estimates may be > bad? Or what I might be able to do to speed this up? The most likely explanation for the bad rowcount estimates is that there is correlation between the regionid/countyid/cityid columns, only the planner doesn't know it. Can you reformulate that data representation at all, or at least avoid depending on it as a join key? regards, tom lane -- Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
