Received: from maia.hub.org (maia-5.hub.org [200.46.204.29]) by mail.postgresql.org (Postfix) with ESMTP id B955EB5DCEB for ; Tue, 26 Jul 2011 14:46:31 -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 02165-04-6 for ; Tue, 26 Jul 2011 17:46:25 +0000 (UTC) X-Greylist: domain auto-whitelisted by SQLgrey-1.7.6 Received: from sam.nabble.com (sam.nabble.com [216.139.236.26]) by mail.postgresql.org (Postfix) with ESMTP id 63D2BB5DC3B for ; Tue, 26 Jul 2011 14:46:06 -0300 (ADT) Received: from [192.168.236.26] (helo=sam.nabble.com) by sam.nabble.com with esmtp (Exim 4.72) (envelope-from ) id 1Qllhi-0007zC-Oo for pgsql-admin@postgresql.org; Tue, 26 Jul 2011 10:46:02 -0700 Date: Tue, 26 Jul 2011 10:46:02 -0700 (PDT) From: Filippos To: pgsql-admin@postgresql.org Message-ID: <1311702362761-4635691.post@n5.nabble.com> Subject: heavy load-high cpu itilization MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Virus-Scanned: Maia Mailguard 1.0.1 X-Spam-Status: No, hits=-0.767 tagged_above=-10 required=5 tests=BAYES_00=-1.9, FREEMAIL_FROM=0.001, T_TO_NO_BRKTS_FREEMAIL=0.01, URI_HEX=1.122 X-Spam-Level: X-Archive-Number: 201107/185 X-Sequence-Number: 37964 Dear all first of all congratulations on your greak work here since from time to time i 've found many answers to my problems. unfortunately for this specific problem i didnt find much relevant information, so i would ask for your guidance dealing with the following situation: we have a dedicated server (8.4.4, redhat) with 24 cpus and 36 GB or RAM. i would say that the traffic in the server is huge and the cpu utilization is pretty high too (avg ~ 75% except during the nights when is it much lower). i am trying to tune the server a little bit to handle this problem. the incoming data in the database are about 30-40 GB /day. at first the checkpoint_segments were set to 50, the checkpoint_timeout at 15 min and the checkpoint_completion_target was 0.5 sec. i noticed that the utilization of the server was higher when it was close to making a checkpoint and since the parameter of full_page_writes is ON , i changed the parameters mentioned above to (i did that after reading a lot of stuff online): checkpoint_segments->250 checkpoint_timeout->40min checkpoint_completion_target -> 0.8 but the cpu utilization is not significantly lower. another parameter i will certainly change is the wal_buffers which is now set at 64KB and i plan to make it 16MB. can this parameter cause a significant percentage of the problem? are there any suggestions what i can do to tune better the server? i can provide any information you find relevant for the configuration of the server, the OS, the storage etc thank you in advance heavy load-high cpu itilization -- View this message in context: http://postgresql.1045698.n5.nabble.com/heavy-load-high-cpu-itilization-tp4635691p4635691.html Sent from the PostgreSQL - admin mailing list archive at Nabble.com.