X-Original-To: pgsql-performance-postgresql.org@localhost.postgresql.org Received: from localhost (mx1.hub.org [200.46.208.251]) by postgresql.org (Postfix) with ESMTP id 61CD89FA5E9 for ; Wed, 31 May 2006 00:20:54 -0300 (ADT) Received: from postgresql.org ([200.46.204.71]) by localhost (mx1.hub.org [200.46.208.251]) (amavisd-new, port 10024) with ESMTP id 70292-03 for ; Wed, 31 May 2006 00:20:50 -0300 (ADT) X-Greylist: from auto-whitelisted by SQLgrey- Received: from sss.pgh.pa.us (sss.pgh.pa.us [66.207.139.130]) by postgresql.org (Postfix) with ESMTP id A86FC9FA5E1 for ; Wed, 31 May 2006 00:20:49 -0300 (ADT) Received: from sss2.sss.pgh.pa.us (tgl@localhost [127.0.0.1]) by sss.pgh.pa.us (8.13.6/8.13.6) with ESMTP id k4V3KkW9006070; Tue, 30 May 2006 23:20:46 -0400 (EDT) To: "wmiro@ig.com.br" cc: pgsql-performance@postgresql.org Subject: Re: Why the 8.1 plan is worst than 7.4? In-reply-to: <20060526_120456_040065.wmiro@ig.com.br> References: <20060526_120456_040065.wmiro@ig.com.br> Comments: In-reply-to "wmiro@ig.com.br" message dated "Fri, 26 May 2006 09:04:56 -0300" Date: Tue, 30 May 2006 23:20:46 -0400 Message-ID: <6069.1149045646@sss.pgh.pa.us> From: Tom Lane X-Virus-Scanned: Maia Mailguard 1.0.1 X-Archive-Number: 200605/561 X-Sequence-Number: 19348 "wmiro@ig.com.br" writes: > Why the plan is worst in postgres 8.1? (1) you have not actually shown us that the plan is worse. If you are complaining that the planner is wrong, EXPLAIN output (which contains only the planner's estimates) is useless for proving your point. Show EXPLAIN ANALYZE. (2) Have you ANALYZEd these tables recently in either database? The discrepancies in estimated rowcounts suggest that the two planners are working with different statistics. regards, tom lane