Received: from maia.hub.org (maia-5.hub.org [200.46.204.29]) by mail.postgresql.org (Postfix) with ESMTP id 416466321F9 for ; Wed, 4 Aug 2010 16:20:22 -0300 (ADT) Received: from mail.postgresql.org ([200.46.204.86]) by maia.hub.org (mx1.hub.org [200.46.204.29]) (amavisd-maia, port 10024) with ESMTP id 43987-05 for ; Wed, 4 Aug 2010 19:20:15 +0000 (UTC) X-Greylist: from auto-whitelisted by SQLgrey-1.7.6 Received: from sss.pgh.pa.us (sss.pgh.pa.us [66.207.139.130]) by mail.postgresql.org (Postfix) with ESMTP id CFABF632AA4 for ; Wed, 4 Aug 2010 16:20:14 -0300 (ADT) Received: from sss2.sss.pgh.pa.us (tgl@localhost [127.0.0.1]) by sss.pgh.pa.us (8.14.2/8.14.2) with ESMTP id o74JK8WP024450; Wed, 4 Aug 2010 15:20:08 -0400 (EDT) To: Hannu Krosing cc: Robert Haas , Peter Hussey , pgsql-performance Subject: Re: Questions on query planner, join types, and work_mem In-reply-to: <1280948634.3735.69.camel@hvost> References: <18551.1280275502@sss.pgh.pa.us> <25534.1280498632@sss.pgh.pa.us> <1280819031.14579.38.camel@hvost> <1280944268.3735.12.camel@hvost> <22961.1280944836@sss.pgh.pa.us> <1280947287.3735.56.camel@hvost> <1280948634.3735.69.camel@hvost> Comments: In-reply-to Hannu Krosing message dated "Wed, 04 Aug 2010 22:03:54 +0300" Date: Wed, 04 Aug 2010 15:20:08 -0400 Message-ID: <24449.1280949608@sss.pgh.pa.us> From: Tom Lane X-Virus-Scanned: Maia Mailguard 1.0.1 X-Spam-Status: No, hits=-1.91 tagged_above=-10 required=5 tests=BAYES_00=-1.9, T_RP_MATCHES_RCVD=-0.01 X-Spam-Level: X-Archive-Number: 201008/54 X-Sequence-Number: 39897 Hannu Krosing writes: > There was ample space for keeping the indexes in linux cache (it has 1GB > cached currently) though the system may have decided to start writing it > to disk, so I suspect that most of the time was spent copying random > index pages back and forth between shared buffers and disk cache. If you're on a platform that has oprofile, you could probably verify that rather than just guess it ... regards, tom lane