Received: from localhost (unknown [200.46.204.183]) by postgresql.org (Postfix) with ESMTP id 4196D9FB68F for ; Wed, 17 Oct 2007 10:15:37 -0300 (ADT) Received: from postgresql.org ([200.46.204.71]) by localhost (mx1.hub.org [200.46.204.183]) (amavisd-maia, port 10024) with ESMTP id 82557-04 for ; Wed, 17 Oct 2007 10:15:33 -0300 (ADT) X-Greylist: from auto-whitelisted by SQLgrey-1.7.5 Received: from cassarossa.samfundet.no (cassarossa.samfundet.no [129.241.93.19]) by postgresql.org (Postfix) with ESMTP id 67A039FB831 for ; Wed, 17 Oct 2007 10:15:33 -0300 (ADT) Received: from trofast.ipv6.sesse.net ([2001:700:300:1803:20e:cff:fe36:a766] helo=trofast.sesse.net) by cassarossa.samfundet.no with esmtps (TLS-1.0:RSA_AES_256_CBC_SHA1:32) (Exim 4.63) (envelope-from ) id 1Ii8kD-00084g-Dv; Wed, 17 Oct 2007 15:15:30 +0200 Received: from root by trofast.sesse.net with local (Exim 4.68) (envelope-from ) id 1Ii8k8-0000to-KC; Wed, 17 Oct 2007 15:15:24 +0200 Date: Wed, 17 Oct 2007 15:15:24 +0200 From: "Steinar H. Gunderson" To: Stefano Dal Pra Cc: pgsql-sql@postgresql.org, pgsql-performance@postgresql.org Subject: Re: two queryes in a single tablescan Message-ID: <20071017131524.GC3237@uio.no> Mail-Followup-To: Stefano Dal Pra , pgsql-sql@postgresql.org, pgsql-performance@postgresql.org References: <290a5abc0710170530v215cb2b0q4fa000ad43096a28@mail.gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <290a5abc0710170530v215cb2b0q4fa000ad43096a28@mail.gmail.com> X-Operating-System: Linux 2.6.20.4 on a x86_64 X-Message-Flag: Outlook? --> http://www.mozilla.org/products/thunderbird/ User-Agent: Mutt/1.5.16 (2007-06-11) X-Virus-Scanned: Maia Mailguard 1.0.1 X-Archive-Number: 200710/199 X-Sequence-Number: 27221 On Wed, Oct 17, 2007 at 02:30:52PM +0200, Stefano Dal Pra wrote: > The main goal would be to get multiple results while scanning the > table[s] once only > thus getting results in a faster way. In 8.3, Postgres will do this for you itself -- if you already have a sequential scan running against a given table, another one starting in parallel will simply piggyback it. /* Steinar */ -- Homepage: http://www.sesse.net/