Received: from malur.postgresql.org ([217.196.149.56]) by arkaria.postgresql.org with esmtp (Exim 4.72) (envelope-from ) id 1U8IP9-0008FP-Kh for pgsql-performance@arkaria.postgresql.org; Wed, 20 Feb 2013 22:44:47 +0000 Received: from localhost ([127.0.0.1] helo=postgresql.org) by malur.postgresql.org with smtp (Exim 4.72) (envelope-from ) id 1U8IP8-0000yi-U0 for pgsql-performance@arkaria.postgresql.org; Wed, 20 Feb 2013 22:44:46 +0000 Received: from magus.postgresql.org ([2a02:c0:301:0:ffff::29]) by malur.postgresql.org with esmtp (Exim 4.72) (envelope-from ) id 1U8IP7-0000yc-Ry for pgsql-performance@postgresql.org; Wed, 20 Feb 2013 22:44:45 +0000 Received: from outmail148152.authsmtp.com ([62.13.148.152]) by magus.postgresql.org with esmtp (Exim 4.72) (envelope-from ) id 1U8IP2-000278-8g for pgsql-performance@postgresql.org; Wed, 20 Feb 2013 22:44:45 +0000 Received: from mail-c233.authsmtp.com (mail-c233.authsmtp.com [62.13.128.233]) by punt9.authsmtp.com (8.14.2/8.14.2/Kp) with ESMTP id r1KMicIp077564; Wed, 20 Feb 2013 22:44:38 GMT Received: from [172.47.23.103] (70-36-143-10.dsl.dynamic.sonic.net [70.36.143.10]) (authenticated bits=0) by mail.authsmtp.com (8.14.2/8.14.2/) with ESMTP id r1KMiZmf047291; Wed, 20 Feb 2013 22:44:36 GMT Message-ID: <512551D2.9090407@agliodbs.com> Date: Wed, 20 Feb 2013 14:44:34 -0800 From: Josh Berkus Organization: PostgreSQL Experts Inc. User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130106 Thunderbird/17.0.2 MIME-Version: 1.0 To: Scott Marlowe CC: pgsql-performance@postgresql.org Subject: Re: High CPU usage / load average after upgrading to Ubuntu 12.04 References: <60B572D9298D944580F7D51195DD30804357FA4ABF@VMBX125.ihostexchange.net> <60B572D9298D944580F7D51195DD30804357FA4C11@VMBX125.ihostexchange.net> <511BE879.8080706@agliodbs.com> <511C2F10.3080409@agliodbs.com> <60B572D9298D944580F7D51195DD30804357FA4DE2@VMBX125.ihostexchange.net> <511D2F11.6040706@agliodbs.com> <60B572D9298D944580F7D51195DD308043580CAA0B@VMBX125.ihostexchange.net> <511D79FE.7060705@agliodbs.com> <60B572D9298D944580F7D51195DD308043580CAA87@VMBX125.ihostexchange.net> <511E7DC0.4090506@agliodbs.com> <5122C507.7060303@agliodbs.com> <5122FF50.8030903@catalyst.net.nz> <5123BB94.7030603@agliodbs.com> <512409AF.8010308@agliodbs.com> In-Reply-To: X-Enigmail-Version: 1.5 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Server-Quench: 1a73b313-7baf-11e2-a49c-0025907707a1 X-AuthReport-Spam: If SPAM / abuse - report it at: http://www.authsmtp.com/abuse X-AuthRoute: OCdyZgscClZXSx8a IioLCC5HRQ8+YBZL BAkGMA9GIUINWEQL c1AAdh19PVdbHwkA AHYJWV5QVFdyXy1y axRSaxtcZklQXgV1 UktWQhwQFX4VWHZc UB4aVRt7dktCcHh2 K0czWXMJX0V5aEEv ExhJFGxTZ3oxbGlM TUBYdQZdcARNfhgU ax4dAXkdCgVyBAwf JSoGdxAwMjUXAxxo ChwWJF0fCQFDGjk1 S1gLAzg1FEIIDyw9 MxE8YkMEE1wYPkQ0 PhM9XholOQIUFhA8 VxgXRncFT+v/ X-Authentic-SMTP: 61633136333939.1021:706 X-AuthFastPath: 0 (Was 255) X-AuthSMTP-Origin: 70.36.143.10/23 X-AuthVirus-Status: No virus detected - but ensure you scan with your own anti-virus system. X-Pg-Spam-Score: -2.6 (--) List-Archive: List-Help: List-ID: List-Owner: List-Post: List-Subscribe: List-Unsubscribe: X-Mailing-List: pgsql-performance Precedence: bulk Sender: pgsql-performance-owner@postgresql.org On 02/19/2013 07:15 PM, Scott Marlowe wrote: > On Tue, Feb 19, 2013 at 4:24 PM, Josh Berkus wrote: >> ... then you'll see checkpoint "stalls" and spread checkpoint will >> actually make them worse by making the stalls longer. > > Wait, if they're spread enough then there won't be a checkpoint, so to > speak. Are you saying that spreading them out means that they still > kind of pile up, even with say a completion target of 1.0 etc? I'm saying that spreading them makes things worse, because they get intermixed with the fsyncs for the WAL and causes commits to stall. I tried setting checkpoint_completion_target = 0.0 and throughput got about 10% better. I'm beginning to think that checkpoint_completion_target should be 0.0, by default. -- Josh Berkus PostgreSQL Experts Inc. http://pgexperts.com -- Sent via pgsql-performance mailing list (pgsql-performance@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance