Received: from maia.hub.org (maia-5.hub.org [200.46.204.29]) by mail.postgresql.org (Postfix) with ESMTP id A697F6328D3 for ; Fri, 25 Jun 2010 01:05:01 -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 59702-06 for ; Fri, 25 Jun 2010 04:04:54 +0000 (UTC) X-Greylist: from auto-whitelisted by SQLgrey-1.7.6 Received: from sss.pgh.pa.us (sss.pgh.pa.us [66.207.139.130]) by mail.postgresql.org (Postfix) with ESMTP id 71511632795 for ; Fri, 25 Jun 2010 01:04:54 -0300 (ADT) Received: from sss2.sss.pgh.pa.us (tgl@localhost [127.0.0.1]) by sss.pgh.pa.us (8.14.2/8.14.2) with ESMTP id o5P44qsV023597; Fri, 25 Jun 2010 00:04:53 -0400 (EDT) To: Craig James cc: pgsql-performance@postgresql.org Subject: Re: Occasional giant spikes in CPU load In-reply-to: <4C23FD52.40508@emolecules.com> References: <4BBCFB12.1010306@emolecules.com> <4BBD3A17.90209@emolecules.com> <4C23FD52.40508@emolecules.com> Comments: In-reply-to Craig James message dated "Thu, 24 Jun 2010 17:50:26 -0700" Date: Fri, 25 Jun 2010 00:04:52 -0400 Message-ID: <23596.1277438692@sss.pgh.pa.us> From: Tom Lane X-Virus-Scanned: Maia Mailguard 1.0.1 X-Spam-Status: No, hits=-1.91 tagged_above=-10 required=5 tests=BAYES_00=-1.9, T_RP_MATCHES_RCVD=-0.01 X-Spam-Level: X-Archive-Number: 201006/457 X-Sequence-Number: 39313 Craig James writes: > So what is it that will cause every single Postgres backend to come to life at the same moment, when there's no real load on the server? Maybe if a backend crashes? Some other problem? sinval queue overflow comes to mind ... although that really shouldn't happen if there's "no real load" on the server. What PG version is this? Also, the pg_stat_activity view contents when this happens would probably be more useful to look at than "top" output. regards, tom lane