X-Original-To: pgsql-performance-postgresql.org@localhost.postgresql.org Received: from localhost (av.hub.org [200.46.204.144]) by postgresql.org (Postfix) with ESMTP id 9A29A9DCAA5 for ; Sat, 3 Dec 2005 15:32:39 -0400 (AST) Received: from postgresql.org ([200.46.204.71]) by localhost (av.hub.org [200.46.204.144]) (amavisd-new, port 10024) with ESMTP id 41271-02 for ; Sat, 3 Dec 2005 15:32:36 -0400 (AST) X-Greylist: from auto-whitelisted by SQLgrey- Received: from smtp105.mail.sc5.yahoo.com (smtp105.mail.sc5.yahoo.com [66.163.169.225]) by postgresql.org (Postfix) with SMTP id 66E3E9DCA94 for ; Sat, 3 Dec 2005 15:32:36 -0400 (AST) Received: (qmail 78681 invoked from network); 3 Dec 2005 19:32:33 -0000 DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=s1024; d=Yahoo.com; h=Received:Received:Message-ID:Date:From:User-Agent:X-Accept-Language:MIME-Version:To:CC:Subject:References:In-Reply-To:Content-Type:Content-Transfer-Encoding; b=YOWNi8L4iPNpQn8yWhYNHEd0u+X2pBK9zLb09AgkZKnUPEubg97aTqOjtmIwui60xLQuTbeJDb7+NwCcVwIJFDBbSEN9WPvyaTPQ5XOW1Hsy6nXmTO5fS6Q5tyyg5CIOfhqaatxaT7PWhLdlGeUe7tlQ++UFPUk7LHVn+vgiULw= ; Received: from unknown (HELO jupiter.black-lion.info) (janwieck@68.80.245.191 with login) by smtp105.mail.sc5.yahoo.com with SMTP; 3 Dec 2005 19:32:33 -0000 Received: from [172.21.8.23] (mars.black-lion.info [192.168.192.101]) (authenticated bits=0) by jupiter.black-lion.info (8.12.10/8.12.9) with ESMTP id jB3JWV1o004966; Sat, 3 Dec 2005 14:32:32 -0500 (EST) (envelope-from JanWieck@Yahoo.com) Message-ID: <4391F2C5.9040009@Yahoo.com> Date: Sat, 03 Dec 2005 14:32:21 -0500 From: Jan Wieck User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.0; en-US; rv:1.7.1) Gecko/20040707 X-Accept-Language: en-us, en MIME-Version: 1.0 To: Michael Riess CC: pgsql-performance@postgresql.org Subject: Re: 15,000 tables - next step References: <4391BF0F.9000208@Yahoo.com> <20051203162642.GA29022@surnet.cl> In-Reply-To: Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit X-Virus-Scanned: by amavisd-new at hub.org X-Spam-Status: No, score=0.348 required=5 tests=[AWL=-0.131, DNS_FROM_RFC_ABUSE=0.479] X-Spam-Score: 0.348 X-Spam-Level: X-Archive-Number: 200512/102 X-Sequence-Number: 15923 On 12/3/2005 11:41 AM, Michael Riess wrote: > Alvaro Herrera schrieb: >> Michael Riess wrote: >> >>> Shared memory ... I currently use 1500 buffers for 50 connections, and >>> performance really suffered when I used 3000 buffers. The problem is >>> that it is a 1GB machine, and Apache + Tomcat need about 400MB. >> >> Well, I'd think that's were your problem is. Not only you have a >> (relatively speaking) small server -- you also share it with other >> very-memory-hungry services! That's not a situation I'd like to be in. >> Try putting Apache and Tomcat elsewhere, and leave the bulk of the 1GB >> to Postgres. > > No can do. I can try to switch to a 2GB machine, but I will not use > several machines. Not for a 5GB database. ;-) What version of PostgreSQL are we talking about? If it is anything older than 8.0, you should upgrade at least to that. With 8.0 or better try 20000 shared buffers or more. It is well possible that going from 1500 to 3000 buffers made things worse. Your buffer cache can't even hold the system catalog in shared memory. If those 50 backends serve all those 500 apps at the same time, they suffer from constant catalog cache misses and don't find the entries in the shared buffers either. Jan -- #======================================================================# # It's easier to get forgiveness for being wrong than for being right. # # Let's break this rule - forgive me. # #================================================== JanWieck@Yahoo.com #