Received: from localhost (unknown [200.46.204.183]) by postgresql.org (Postfix) with ESMTP id EBC752E003D for ; Mon, 25 Feb 2008 13:42:45 -0400 (AST) Received: from postgresql.org ([200.46.204.71]) by localhost (mx1.hub.org [200.46.204.183]) (amavisd-maia, port 10024) with ESMTP id 63155-06 for ; Mon, 25 Feb 2008 13:42:27 -0400 (AST) X-Greylist: domain auto-whitelisted by SQLgrey-1.7.5 Received: from smtpoutm.mac.com (smtpoutm.mac.com [17.148.16.78]) by postgresql.org (Postfix) with ESMTP id 222E32E002F for ; Mon, 25 Feb 2008 13:42:27 -0400 (AST) Received: from mac.com (asmtp004-s [10.150.69.67]) by smtpoutm.mac.com (Xserve/smtpout015/MantshX 4.0) with ESMTP id m1PHgQB8019648 for ; Mon, 25 Feb 2008 09:42:26 -0800 (PST) Received: from [192.168.0.9] ([38.99.35.195]) (authenticated bits=0) by mac.com (Xserve/asmtp004/MantshX 4.0) with ESMTP id m1PHgMuk010698 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO); Mon, 25 Feb 2008 09:42:24 -0800 (PST) Mime-Version: 1.0 Message-Id: Date: Mon, 25 Feb 2008 09:42:12 -0800 To: pgsql-performance@postgresql.org From: Joel Stevenson Subject: Re: LISTEN / NOTIFY performance in 8.3 Content-Type: text/plain; charset="us-ascii" ; format="flowed" X-Virus-Scanned: Maia Mailguard 1.0.1 X-Spam-Status: No, hits=0 tagged_above=0 required=5 tests=none X-Spam-Level: X-Archive-Number: 200802/325 X-Sequence-Number: 28867 >Also, it might be worth enabling log_lock_waits to see if the slow >notifies are due to having to wait on some lock or other. Turning on log_lock_waits shows that there is a lot of waiting for locks on the pg_listener table ala: process 22791 still waiting for ExclusiveLock on relation 2614 of database 16387 after 992.397 ms ... process 22791 acquired ExclusiveLock on relation 2614 of database 16387 after 1433.152 ms deadlock_timeout is left at the default 1s setting. Though these are being generated during application activity - running the simulation script does produce 300ms - 600ms NOTIFY statements but doesn't (at the moment) trigger a lock_wait log entry.