Received: from localhost (maia-5.hub.org [200.46.204.182]) by postgresql.org (Postfix) with ESMTP id 9C3199FB377 for ; Thu, 19 Jul 2007 16:04:47 -0300 (ADT) Received: from postgresql.org ([200.46.204.71]) by localhost (mx1.hub.org [200.46.204.182]) (amavisd-maia, port 10024) with ESMTP id 60649-05 for ; Thu, 19 Jul 2007 16:04:41 -0300 (ADT) X-Greylist: from auto-whitelisted by SQLgrey-1.7.5 Received: from westnet.com (westnet.com [216.187.52.2]) by postgresql.org (Postfix) with ESMTP id BB5169FB24B for ; Thu, 19 Jul 2007 16:04:43 -0300 (ADT) Received: from westnet.com (localhost [127.0.0.1]) by westnet.com (8.14.0/8.14.0) with ESMTP id l6JJ4iwe003531 for ; Thu, 19 Jul 2007 15:04:44 -0400 (EDT) Received: from localhost (gsmith@localhost) by westnet.com (8.14.0/8.13.2/Submit) with ESMTP id l6JJ4ieq003528 for ; Thu, 19 Jul 2007 15:04:44 -0400 (EDT) X-Authentication-Warning: westnet.com: gsmith owned process doing -bs Date: Thu, 19 Jul 2007 15:04:44 -0400 (EDT) From: Greg Smith X-X-Sender: gsmith@westnet.com To: pgsql-performance@postgresql.org Subject: Re: User concurrency thresholding: where do I look? In-Reply-To: <200707190828.59088.josh@agliodbs.com> Message-ID: References: <200707190828.59088.josh@agliodbs.com> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed X-Virus-Scanned: Maia Mailguard 1.0.1 X-Archive-Number: 200707/250 X-Sequence-Number: 25934 On Thu, 19 Jul 2007, Josh Berkus wrote: > What seems to be happening is that at some specific number of > connections average throughput drops 30% and response time quadruples or > worse. Could you characterize what each connection is doing and how you're generating the load? I don't know how productive speculating about the cause here will be until there's a test script available so other people can see where the tipping point is on their system. -- * Greg Smith gsmith@gregsmith.com http://www.gregsmith.com Baltimore, MD