Received: from maia.hub.org (maia-2.hub.org [200.46.204.251]) by mail.postgresql.org (Postfix) with ESMTP id 98A421337BE4 for ; Wed, 4 May 2011 21:03:17 -0300 (ADT) Received: from mail.postgresql.org ([200.46.204.86]) by maia.hub.org (mx1.hub.org [200.46.204.251]) (amavisd-maia, port 10024) with ESMTP id 48708-01 for ; Thu, 5 May 2011 00:02:59 +0000 (UTC) X-Greylist: from auto-whitelisted by SQLgrey-1.7.6 Received: from smtp-2.01.com (smtp-2.01.com [38.102.63.181]) by mail.postgresql.org (Postfix) with ESMTP id 3591B1337BF2 for ; Wed, 4 May 2011 21:02:59 -0300 (ADT) Received: from localhost (localhost.localdomain [127.0.0.1]) by smtp-2.01.com (Postfix) with ESMTP id 864DE1AD552 for ; Wed, 4 May 2011 19:02:59 -0500 (CDT) Received: from smtp-2.01.com ([127.0.0.1]) by localhost (smtp-2.01.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id yyZxRVYG+N84 for ; Wed, 4 May 2011 19:02:59 -0500 (CDT) Received: by smtp-2.01.com (Postfix, from userid 99) id 699601AD432; Wed, 4 May 2011 19:02:59 -0500 (CDT) Received: from Sidney-Stratton.local (70-36-143-243.dsl.dynamic.sonic.net [70.36.143.243]) by smtp-2.01.com (Postfix) with ESMTPSA id 30D601AD4C3 for ; Wed, 4 May 2011 19:02:59 -0500 (CDT) Message-ID: <4DC1E92D.5020904@agliodbs.com> Date: Wed, 04 May 2011 17:02:53 -0700 From: Josh Berkus Organization: PostgreSQL Experts Inc. User-Agent: Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10.5; en-US; rv:1.9.2.15) Gecko/20110303 Lightning/1.0b2 Thunderbird/3.1.9 MIME-Version: 1.0 To: postgres performance list Subject: Re: amazon ec2 References: <201105031241.20348.ahodgson@simkin.ca> <201105031309.52154.ahodgson@simkin.ca> <4DC08420.7050602@2ndquadrant.com> <00C0C53C-7042-4C05-B6CD-68BFDF400C76@nasby.net> In-Reply-To: <00C0C53C-7042-4C05-B6CD-68BFDF400C76@nasby.net> X-Enigmail-Version: 1.1.1 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Virus-Scanned: Maia Mailguard 1.0.1 X-Spam-Status: No, hits=-1.9 tagged_above=-10 required=5 tests=BAYES_00=-1.9 X-Spam-Level: X-Archive-Number: 201105/55 X-Sequence-Number: 43564 > FWIW, EnterpriseDB's "InfiniCache" provides the same caching benefit. The way that works is when PG goes to evict a page from shared buffers that page gets compressed and stuffed into a memcache cluster. When PG determines that a given page isn't in shared buffers it will then check that memcache cluster before reading the page from disk. This allows you to cache amounts of data that far exceed the amount of memory you could put in a physical server. So memcached basically replaces the filesystem? That sounds cool, but I'm wondering if it's actually a performance speedup. Seems like it would only be a benefit for single-row lookups; any large reads would be a mess. -- Josh Berkus PostgreSQL Experts Inc. http://pgexperts.com