X-Original-To: pgsql-performance-postgresql.org@localhost.postgresql.org Received: from localhost (av.hub.org [200.46.204.144]) by postgresql.org (Postfix) with ESMTP id 91E939DC84E for ; Fri, 16 Dec 2005 17:56:54 -0400 (AST) Received: from postgresql.org ([200.46.204.71]) by localhost (av.hub.org [200.46.204.144]) (amavisd-new, port 10024) with ESMTP id 52330-07 for ; Fri, 16 Dec 2005 17:56:54 -0400 (AST) X-Greylist: from auto-whitelisted by SQLgrey- Received: from flake.decibel.org (flake.decibel.org [67.100.216.10]) by postgresql.org (Postfix) with ESMTP id 65EF79DCCFC for ; Fri, 16 Dec 2005 17:56:50 -0400 (AST) Received: by flake.decibel.org (Postfix, from userid 1001) id CB7DF1525C; Fri, 16 Dec 2005 15:56:52 -0600 (CST) Date: Fri, 16 Dec 2005 15:56:52 -0600 From: "Jim C. Nasby" To: Ameet Kini Cc: pgsql-performance@postgresql.org Subject: Re: Lots of postmaster processes (fwd) Message-ID: <20051216215652.GS53809@pervasive.com> References: Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Operating-System: FreeBSD 4.11-RELEASE-p10 i386 X-Distributed: Join the Effort! http://www.distributed.net User-Agent: Mutt/1.5.9i X-Virus-Scanned: by amavisd-new at hub.org X-Spam-Status: No, score=0.005 required=5 tests=[AWL=0.005] X-Spam-Score: 0.005 X-Spam-Level: X-Archive-Number: 200512/407 X-Sequence-Number: 16228 Dunno if this has gotten a reply elsewhere, but during a checkpoint the database can become quite busy. If that happens and performance slows down, other queries will slow down as well. If you have an app where a a high rate of incomming requests (like a busy website), existing backends won't be able to keep up with demand, so incomming connections will end up spawning more connections to the database. On Tue, Dec 13, 2005 at 11:25:40AM -0600, Ameet Kini wrote: > > > Resending it here as it may be more relevant here... > Ameet > > ---------- Forwarded message ---------- > Date: Tue, 13 Dec 2005 11:24:26 -0600 (CST) > From: Ameet Kini > To: pgsql-admin@postgresql.org > Subject: Lots of postmaster processes > > > > In our installation of the postgres 7.4.7, we are seeing a lot of the > following postmaster processes (around 50) being spawned by the initial > postmaster process once in a while: > > postgres 3977 1 1 Nov03 ? 15:11:38 > /s/postgresql-7.4.7/bin/postmaster -D /scratch.1/postgres/condor-db-7.4.7 > > ...... > > postgres 31985 3977 0 10:08 ? 00:00:00 > /s/postgresql-7.4.7/bin/postmaster -D /scratch.1/postgres/condor-db-7.4.7 > > postgres 31986 3977 0 10:08 ? 00:00:00 > /s/postgresql-7.4.7/bin/postmaster -D /scratch.1/postgres/condor-db-7.4.7 > > postgres 31987 3977 0 10:08 ? 00:00:00 > /s/postgresql-7.4.7/bin/postmaster -D /scratch.1/postgres/condor-db-7.4.7 > > postgres 31988 3977 0 10:08 ? 00:00:00 > /s/postgresql-7.4.7/bin/postmaster -D /scratch.1/postgres/condor-db-7.4.7 > > ...... > > > At the same time when these processes being spawned, sometimes there is > also the checkpoint subprocess. I am not sure if that is related. The > document doesn't provide any information. The other activity going on at > the same time is a 'COPY' statement from a client application. > > These extra processes put a considerable load on the machine and cause it > to hang up. > > Thanks, > Ameet > > ---------------------------(end of broadcast)--------------------------- > TIP 1: if posting/reading through Usenet, please send an appropriate > subscribe-nomail command to majordomo@postgresql.org so that your > message can get through to the mailing list cleanly > -- Jim C. Nasby, Sr. Engineering Consultant jnasby@pervasive.com Pervasive Software http://pervasive.com work: 512-231-6117 vcard: http://jim.nasby.net/pervasive.vcf cell: 512-569-9461