Received: from localhost (unknown [200.46.208.211]) by mail.postgresql.org (Postfix) with ESMTP id E38F9632B9F for ; Thu, 7 Jan 2010 14:10:33 -0400 (AST) Received: from mail.postgresql.org ([200.46.204.86]) by localhost (mx1.hub.org [200.46.208.211]) (amavisd-maia, port 10024) with ESMTP id 97908-07 for ; Thu, 7 Jan 2010 18:10:21 +0000 (UTC) X-Greylist: from auto-whitelisted by SQLgrey-1.7.6 Received: from mta.4linux.com.br (boca.4linux.com.br [200.212.122.137]) by mail.postgresql.org (Postfix) with ESMTP id 3AC14632284 for ; Thu, 7 Jan 2010 14:10:23 -0400 (AST) Received: from localhost (localhost.localdomain [127.0.0.1]) by mta.4linux.com.br (Postfix) with ESMTP id 1C422C815; Thu, 7 Jan 2010 15:10:21 -0300 (BRT) X-Virus-Scanned: amavisd-new at mta.4linux.com.br Received: from mta.4linux.com.br ([127.0.0.1]) by localhost (mta.4linux.com.br [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id 9Zsi4JltUVtC; Thu, 7 Jan 2010 15:10:20 -0300 (BRT) Received: from mail.4linux.com.br (unknown [192.168.0.11]) by mta.4linux.com.br (Postfix) with ESMTP id B16EBC61D; Thu, 7 Jan 2010 15:10:20 -0300 (BRT) Date: Thu, 7 Jan 2010 16:10:21 -0200 (BRST) From: "Gurgel, Flavio" To: Scott Marlowe Cc: Matthew Wakeling , Lefteris , pgsql-performance@postgresql.org, Ivan Voras Message-ID: <21221819.49291262887821207.JavaMail.root@mail.4linux.com.br> In-Reply-To: Subject: Re: Air-traffic benchmark MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit X-Originating-IP: [192.168.0.185] X-Mailer: Zimbra 6.0.0_GA_1802.UBUNTU6 (ZimbraWebClient - FF3.0 (Linux)/6.0.0_GA_1802.UBUNTU6) X-Virus-Scanned: Maia Mailguard 1.0.1 X-Spam-Status: No, hits=-1.082 tagged_above=-10 required=5 tests=AWL=-0.897, BAYES_40=-0.185 X-Spam-Level: X-Archive-Number: 201001/113 X-Sequence-Number: 36993 ----- "Scott Marlowe" escreveu: > You do know that indexes in postgresql are not "covering" right? > I.e. > after hitting the index, the db then has to hit the table to see if > those rows are in fact visible. So there's no such thing in pgsql, > at > the moment, as an index only scan. That was just an estimation of effort to reach a tuple through seqscan X indexscan. In both cases the tuple have to be checked, sure. Flavio Henrique A. Gurgel tel. 55-11-2125.4786 cel. 55-11-8389.7635 www.4linux.com.br FREE SOFTWARE SOLUTIONS