Received: from localhost (unknown [200.46.208.211]) by mail.postgresql.org (Postfix) with ESMTP id D225063347A for ; Thu, 7 Jan 2010 10:52:14 -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 59194-01 for ; Thu, 7 Jan 2010 14:51:55 +0000 (UTC) X-Greylist: domain auto-whitelisted by SQLgrey-1.7.6 Received: from lo.gmane.org (lo.gmane.org [80.91.229.12]) by mail.postgresql.org (Postfix) with ESMTP id EDB33632AC3 for ; Thu, 7 Jan 2010 10:52:03 -0400 (AST) Received: from list by lo.gmane.org with local (Exim 4.50) id 1NStiO-0007XN-7h for pgsql-performance@postgresql.org; Thu, 07 Jan 2010 15:51:56 +0100 Received: from 89-164-111-99.dsl.iskon.hr ([89.164.111.99]) by main.gmane.org with esmtp (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Thu, 07 Jan 2010 15:51:56 +0100 Received: from ivoras by 89-164-111-99.dsl.iskon.hr with local (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Thu, 07 Jan 2010 15:51:56 +0100 X-Injected-Via-Gmane: http://gmane.org/ To: pgsql-performance@postgresql.org From: Ivan Voras Subject: Re: Air-traffic benchmark Date: Thu, 07 Jan 2010 15:51:26 +0100 Lines: 25 Message-ID: References: <852badbc1001070438j36eb10d3qa22398ffcbef405f@mail.gmail.com> <4B45E36E.4040706@tweakers.net> <852badbc1001070547p48b47175vf87efc473e3bd41b@mail.gmail.com> <26014999.20100107150535@erwied.eu> <852badbc1001070610p698dc3cfr4628b1e7768990e6@mail.gmail.com> <20100107141423.GC4315@alvh.no-ip.org> <852badbc1001070623m5d901c42k50bb808409141ca4@mail.gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Complaints-To: usenet@ger.gmane.org X-Gmane-NNTP-Posting-Host: 89-164-111-99.dsl.iskon.hr User-Agent: Mozilla/5.0 (Windows; U; Windows NT 6.0; en-US; rv:1.9.1.5) Gecko/20091204 Thunderbird/3.0 In-Reply-To: <852badbc1001070623m5d901c42k50bb808409141ca4@mail.gmail.com> X-Virus-Scanned: Maia Mailguard 1.0.1 X-Spam-Status: No, hits=-1.855 tagged_above=-10 required=5 tests=AWL=-0.745, BAYES_05=-1.11 X-Spam-Level: X-Archive-Number: 201001/95 X-Sequence-Number: 36975 On 7.1.2010 15:23, Lefteris wrote: > I think what you all said was very helpful and clear! The only part > that I still disagree/don't understand is the shared_buffer option:)) Did you ever try increasing shared_buffers to what was suggested (around 4 GB) and see what happens (I didn't see it in your posts)? Shared_buffers can be thought as the PostgreSQLs internal cache. If the pages being scanned for a particular query are in the cache, this will help performance very much on multiple exequtions of the same query. OTOH, since the file system's cache didn't help you significantly, there is low possibility shared_buffers will. It is still worth trying.