Received: from maia.hub.org (unknown [200.46.208.211]) by mail.postgresql.org (Postfix) with ESMTP id 03E16633143 for ; Sun, 7 Mar 2010 13:57:52 -0400 (AST) Received: from mail.postgresql.org ([200.46.204.86]) by maia.hub.org (mx1.hub.org [200.46.208.211]) (amavisd-maia, port 10024) with ESMTP id 24308-09 for ; Sun, 7 Mar 2010 17:57:39 +0000 (UTC) X-Greylist: from auto-whitelisted by SQLgrey-1.7.6 Received: from glacier.frostconsultingllc.com (glacier.frostconsultingllc.com [69.36.227.170]) by mail.postgresql.org (Postfix) with ESMTP id 5B99563312A for ; Sun, 7 Mar 2010 13:57:41 -0400 (AST) Received: from adsl-63-195-55-98.dsl.snfc21.pacbell.net ([63.195.55.98] helo=Sidney-Stratton.local) by glacier.frostconsultingllc.com with esmtpsa (TLSv1:CAMELLIA256-SHA:256) (Exim 4.69) (envelope-from ) id 1NoKjQ-0005bJ-D6; Sun, 07 Mar 2010 09:57:39 -0800 Message-ID: <4B93E906.5030804@agliodbs.com> Date: Sun, 07 Mar 2010 09:57:26 -0800 From: Josh Berkus User-Agent: Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10.5; en-US; rv:1.9.1b3pre) Gecko/20090223 Thunderbird/3.0b2 MIME-Version: 1.0 To: Robert Haas CC: pgsql-performance@postgresql.org Subject: Re: Estimation issue with partitioned tables References: <4B8ACFE7.6040207@agliodbs.com> <603c8f071003030912k5750abadif64cb36d67ab99ae@mail.gmail.com> <4B8ED891.7060405@agliodbs.com> <603c8f071003031807p52f136edh683d19a1d5b46660@mail.gmail.com> In-Reply-To: <603c8f071003031807p52f136edh683d19a1d5b46660@mail.gmail.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Virus-Scanned: Maia Mailguard 1.0.1 X-Spam-Status: No, hits=-2.124 tagged_above=-10 required=5 tests=AWL=0.319, BAYES_00=-2.599, SUBJECT_FUZZY_TION=0.156 X-Spam-Level: X-Archive-Number: 201003/68 X-Sequence-Number: 37893 Robert, >> Yeah, I can generate one pretty easily; the behavior is readily >> observable and repeatable. Will get on it RSN, but at you said, we're >> not doing anything about it for 9.0. Well, I can generate a test case, but on examination it turns out to be nothing to do with partitioning; it's just good old "n-distinct underestimation", and not really related to partitioning or joins. --Josh Berkus