Received: from localhost (unknown [200.46.204.184]) by postgresql.org (Postfix) with ESMTP id 9D74F9FB9A0 for ; Sun, 28 Oct 2007 19:08:42 -0300 (ADT) Received: from postgresql.org ([200.46.204.71]) by localhost (mx1.hub.org [200.46.204.184]) (amavisd-maia, port 10024) with ESMTP id 20187-02 for ; Sun, 28 Oct 2007 19:08:32 -0300 (ADT) X-Greylist: from auto-whitelisted by SQLgrey-1.7.5 Received: from sss.pgh.pa.us (sss.pgh.pa.us [66.207.139.130]) by postgresql.org (Postfix) with ESMTP id 4CD7C9FB9C7 for ; Sun, 28 Oct 2007 19:08:36 -0300 (ADT) Received: from sss2.sss.pgh.pa.us (tgl@localhost [127.0.0.1]) by sss.pgh.pa.us (8.14.1/8.14.1) with ESMTP id l9SM8YZ5008689; Sun, 28 Oct 2007 18:08:34 -0400 (EDT) To: Sami Dalouche cc: pgsql-performance@postgresql.org Subject: Re: Outer joins and Seq scans In-reply-to: <1193606710.9008.12.camel@samlaptop> References: <1193606710.9008.12.camel@samlaptop> Comments: In-reply-to Sami Dalouche message dated "Sun, 28 Oct 2007 22:25:10 +0100" Date: Sun, 28 Oct 2007 18:08:34 -0400 Message-ID: <8688.1193609314@sss.pgh.pa.us> From: Tom Lane X-Virus-Scanned: Maia Mailguard 1.0.1 X-Archive-Number: 200710/336 X-Sequence-Number: 27358 Sami Dalouche writes: > So, what could prevent postgrs from using the index ? You've carefully withheld all the details that might let us guess. If I had to guess anyway, I'd guess this is a pre-8.2 PG release that doesn't know how to rearrange outer joins, but there are any number of other possibilities. If you want useful help on a query planning issue, you generally need to provide - the exact Postgres version - full schema declaration of the relevant tables - exact queries tested - full EXPLAIN ANALYZE output With less info than that, people are just shooting in the dark. regards, tom lane