X-Original-To: pgsql-performance-postgresql.org@localhost.postgresql.org Received: from localhost (unknown [200.46.204.144]) by svr1.postgresql.org (Postfix) with ESMTP id 4E39152BDF for ; Wed, 17 Aug 2005 14:27:10 -0300 (ADT) Received: from svr1.postgresql.org ([200.46.204.71]) by localhost (av.hub.org [200.46.204.144]) (amavisd-new, port 10024) with ESMTP id 62916-03 for ; Wed, 17 Aug 2005 17:27:05 +0000 (GMT) Received: from davinci.ethosmedia.com (server227.ethosmedia.com [209.128.84.227]) by svr1.postgresql.org (Postfix) with ESMTP id 8599752C09 for ; Wed, 17 Aug 2005 14:27:02 -0300 (ADT) X-EthosMedia-Virus-Scanned: no infections found Received: from [63.195.55.98] (account josh@agliodbs.com HELO spooky) by davinci.ethosmedia.com (CommuniGate Pro SMTP 4.1.8) with ESMTP id 7742017; Wed, 17 Aug 2005 10:29:18 -0700 From: Josh Berkus Organization: Aglio Database Solutions To: pgsql-performance@postgresql.org Subject: Re: Need for speed Date: Wed, 17 Aug 2005 10:28:04 -0700 User-Agent: KMail/1.8 Cc: Ulrich Wisser References: <4303003B.3020407@relevanttraffic.se> In-Reply-To: <4303003B.3020407@relevanttraffic.se> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200508171028.05028.josh@agliodbs.com> X-Virus-Scanned: by amavisd-new at hub.org X-Spam-Status: No, hits=0.012 required=5 tests=[AWL=0.012] X-Spam-Level: X-Archive-Number: 200508/207 X-Sequence-Number: 13954 Ulrich, > I believe the biggest problem is disc io. Reports for very recent data > are quite fast, these are used very often and therefor already in the > cache. But reports can contain (and regulary do) very old data. In that > case the whole system slows down. To me this sounds like the recent data > is flushed out of the cache and now all data for all queries has to be > fetched from disc. How large is the database on disk? > My machine has 2GB memory, please find postgresql.conf below. hmmmm ... effective_cache_size? random_page_cost? cpu_tuple_cost? etc. -- Josh Berkus Aglio Database Solutions San Francisco