Received: from maia.hub.org (maia-5.hub.org [200.46.204.29]) by mail.postgresql.org (Postfix) with ESMTP id 93ED46324C9 for ; Thu, 17 Jun 2010 16:59:52 -0300 (ADT) Received: from mail.postgresql.org ([200.46.204.86]) by maia.hub.org (mx1.hub.org [200.46.204.29]) (amavisd-maia, port 10024) with ESMTP id 85470-02 for ; Thu, 17 Jun 2010 19:59:45 +0000 (UTC) X-Greylist: from auto-whitelisted by SQLgrey-1.7.6 Received: from moutng.kundenserver.de (moutng.kundenserver.de [212.227.126.171]) by mail.postgresql.org (Postfix) with ESMTP id 596CB632208 for ; Thu, 17 Jun 2010 16:59:45 -0300 (ADT) Received: from [75.197.106.33] (33.sub-75-197-106.myvzw.com [75.197.106.33]) by mrelayeu.kundenserver.de (node=mreu1) with ESMTP (Nemesis) id 0MJYNz-1OMrCw31sB-002fWE; Thu, 17 Jun 2010 21:59:42 +0200 Message-ID: <4C1A7EAB.3020202@2ndquadrant.com> Date: Thu, 17 Jun 2010 15:59:39 -0400 From: Greg Smith User-Agent: Thunderbird 2.0.0.24 (X11/20100317) MIME-Version: 1.0 To: Josh Berkus CC: postgres performance list Subject: Re: PostgreSQL as a local in-memory cache References: <18287446-8677-46d6-a581-c4777f60ebda@40g2000pry.googlegroups.com> <4C1A5B81.8050908@agliodbs.com> In-Reply-To: <4C1A5B81.8050908@agliodbs.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Provags-ID: V01U2FsdGVkX1/SgdfezEu5N6ccreThXEI9Y3XobSeX3dA1fyK 057BIdTg4pWdlrLJP5l5/ceMf9SYPbGOQ3Dybzqe6yiHlSQDPl Lx6OLe7W6ELXQlC+jx9gj6Cd81UwjNd X-Virus-Scanned: Maia Mailguard 1.0.1 X-Spam-Status: No, hits=-0.001 tagged_above=-10 required=5 tests=BAYES_40=-0.001, RCVD_IN_DNSWL_NONE=-0.0001 X-Spam-Level: X-Archive-Number: 201006/316 X-Sequence-Number: 39172 Josh Berkus wrote: > a) Eliminate WAL logging entirely > c) Turn off the background writer Note that if you turn off full_page_writes and set bgwriter_lru_maxpages=0, you'd get a substantial move in both these directions without touching any code. Would help prove those as useful directions to move toward or not. The difference in WAL writes just after a checkpoint in particular, due to the full_page_writes behavior, is a significant portion of total WAL activity on most systems. -- Greg Smith 2ndQuadrant US Baltimore, MD PostgreSQL Training, Services and Support greg@2ndQuadrant.com www.2ndQuadrant.us