X-Original-To: pgsql-performance-postgresql.org@postgresql.org Received: from localhost (mx1.hub.org [200.46.208.251]) by postgresql.org (Postfix) with ESMTP id 92DC59FA5BA for ; Thu, 22 Jun 2006 13:24:51 -0300 (ADT) Received: from postgresql.org ([200.46.204.71]) by localhost (mx1.hub.org [200.46.208.251]) (amavisd-new, port 10024) with ESMTP id 06304-02 for ; Thu, 22 Jun 2006 13:24:47 -0300 (ADT) X-Greylist: from auto-whitelisted by SQLgrey- Received: from sss.pgh.pa.us (sss.pgh.pa.us [66.207.139.130]) by postgresql.org (Postfix) with ESMTP id 656F29FA2F0 for ; Thu, 22 Jun 2006 13:24:46 -0300 (ADT) Received: from sss2.sss.pgh.pa.us (tgl@localhost [127.0.0.1]) by sss.pgh.pa.us (8.13.6/8.13.6) with ESMTP id k5MGOi6s000767; Thu, 22 Jun 2006 12:24:44 -0400 (EDT) To: Peter Wilson cc: pgsql-performance@postgresql.org Subject: Re: Poor performance - fixed by restart In-reply-to: References: Comments: In-reply-to Peter Wilson message dated "Thu, 22 Jun 2006 00:08:53 +0100" Date: Thu, 22 Jun 2006 12:24:44 -0400 Message-ID: <766.1150993484@sss.pgh.pa.us> From: Tom Lane X-Virus-Scanned: Maia Mailguard 1.0.1 X-Archive-Number: 200606/450 X-Sequence-Number: 19807 Peter Wilson writes: > I'd tweaked a couple of parameters in postgres.conf - the significant one I > thought being random_page_cost, so I changed this back to default and did a > 'service postgresql reload' - no difference, but I wasn't sure whether this > could be changed via reload so I restarted Postgres. > The restart fixed the problem. The 85 second insert time dropped back down to 5 > seconds!!! Um, which parameters did you change *exactly*? Also, depending on how you were submitting the queries, it's possible that Postgres was using cached plans already made based on the old settings. In that case the restart would've cleared the bad plans (but starting a fresh connection would've been sufficient for that). regards, tom lane