Received: from localhost (maia-1.hub.org [200.46.204.191]) by postgresql.org (Postfix) with ESMTP id 5F6F89FA0EE for ; Sun, 31 Dec 2006 13:11:43 -0400 (AST) Received: from postgresql.org ([200.46.204.71]) by localhost (mx1.hub.org [200.46.204.191]) (amavisd-new, port 10024) with ESMTP id 33909-08 for ; Sun, 31 Dec 2006 13:11:33 -0400 (AST) X-Greylist: from auto-whitelisted by SQLgrey-1.7.4 Received: from sss.pgh.pa.us (sss.pgh.pa.us [66.207.139.130]) by postgresql.org (Postfix) with ESMTP id D84039F939F for ; Sun, 31 Dec 2006 13:11:29 -0400 (AST) 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 kBVHBSRh004050; Sun, 31 Dec 2006 12:11:28 -0500 (EST) To: Rolf =?iso-8859-1?q?=D8stvik?= cc: pgsql-performance@postgresql.org Subject: Re: Worse perfomance on 8.2.0 than on 7.4.14 In-reply-to: <200612311233.10201.rolfostvik@yahoo.no> References: <200612311233.10201.rolfostvik@yahoo.no> Comments: In-reply-to Rolf =?iso-8859-1?q?=D8stvik?= message dated "Sun, 31 Dec 2006 12:33:09 +0100" Date: Sun, 31 Dec 2006 12:11:28 -0500 Message-ID: <4049.1167585088@sss.pgh.pa.us> From: Tom Lane X-Virus-Scanned: Maia Mailguard 1.0.1 X-Archive-Number: 200612/545 X-Sequence-Number: 22601 Rolf =?iso-8859-1?q?=D8stvik?= writes: > I have a simple query which uses 32ms on 7.4.14 and 1015ms on 8.2.0. There's something awfully strange about that 8.2 plan --- if it knew that it'd have to scan all of uut_result_subset (which it should have known, if the stats were up-to-date), why did it use an indexscan rather than a seqscan? Are you sure you haven't tweaked any parameters you didn't tell us about, such as setting enable_seqscan = off? regards, tom lane