Received: from localhost (unknown [200.46.204.184]) by developer.postgresql.org (Postfix) with ESMTP id 98EA22E004F for ; Fri, 11 Apr 2008 11:47:39 -0300 (ADT) Received: from developer.postgresql.org ([200.46.204.71]) by localhost (mx1.hub.org [200.46.204.184]) (amavisd-maia, port 10024) with ESMTP id 64083-02-2 for ; Fri, 11 Apr 2008 11:47:24 -0300 (ADT) X-Greylist: from auto-whitelisted by SQLgrey-1.7.5 Received: from oxford.xeocode.com (unknown [62.232.55.118]) by developer.postgresql.org (Postfix) with ESMTP id 8CB242E00C4 for ; Fri, 11 Apr 2008 11:47:19 -0300 (ADT) Received: from localhost ([127.0.0.1] helo=oxford.xeocode.com) by oxford.xeocode.com with esmtp (Exim 4.69) (envelope-from ) id 1JkKX7-0001tg-L8; Fri, 11 Apr 2008 15:47:17 +0100 To: "Albe Laurenz" Cc: Subject: Re: Performance increase with elevator=deadline In-Reply-To: (Albe Laurenz's message of "Fri\, 11 Apr 2008 13\:22\:04 +0200") User-Agent: Gnus/5.11 (Gnus v5.11) Emacs/22.1 (gnu/linux) X-Draft-From: ("nnimap+mail01.enterprisedb.com:INBOX.performance" 5147) References: From: Gregory Stark Organization: EnterpriseDB Date: Fri, 11 Apr 2008 15:47:17 +0100 Message-ID: <878wzkh2iy.fsf@oxford.xeocode.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Virus-Scanned: Maia Mailguard 1.0.1 X-Archive-Number: 200804/154 X-Sequence-Number: 29647 "Albe Laurenz" writes: > This refers to the performance problem reported in > http://archives.postgresql.org/pgsql-performance/2008-04/msg00052.php > > After some time of trial and error we found that changing the I/O scheduling > algorithm to "deadline" improved I/O performance by a factor 4 (!) for > this specific load test. What was the algorithm before? -- Gregory Stark EnterpriseDB http://www.enterprisedb.com Ask me about EnterpriseDB's On-Demand Production Tuning