X-Original-To: pgsql-performance-postgresql.org@localhost.postgresql.org Received: from localhost (unknown [200.46.204.144]) by svr1.postgresql.org (Postfix) with ESMTP id AD4855286A for ; Tue, 19 Jul 2005 11:49:10 -0300 (ADT) Received: from svr1.postgresql.org ([200.46.204.71]) by localhost (av.hub.org [200.46.204.144]) (amavisd-new, port 10024) with ESMTP id 49865-01 for ; Tue, 19 Jul 2005 14:49:06 +0000 (GMT) Received: from wproxy.gmail.com (wproxy.gmail.com [64.233.184.200]) by svr1.postgresql.org (Postfix) with ESMTP id F15A952995 for ; Tue, 19 Jul 2005 11:49:05 -0300 (ADT) Received: by wproxy.gmail.com with SMTP id i35so1210895wra for ; Tue, 19 Jul 2005 07:49:10 -0700 (PDT) DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=beta; d=gmail.com; h=received:message-id:date:from:reply-to:to:subject:cc:in-reply-to:mime-version:content-type:content-transfer-encoding:content-disposition:references; b=mhQ0B63ZLQYyzMAVfvQujUqo4yn7S6vRV/eccVvASR+wKrY/MBh3j3eotGoofM1GNySAFXemSreRhyrao6Qh0bpJakI4mo/hOePvdnfIcGL38armR0gnx0oiLZYNIRQWvyd7345NuzWbiIUQLiMyYg11VMErjTgoHK30N6/z9vA= Received: by 10.54.50.62 with SMTP id x62mr752726wrx; Tue, 19 Jul 2005 07:48:42 -0700 (PDT) Received: by 10.54.120.11 with HTTP; Tue, 19 Jul 2005 07:48:42 -0700 (PDT) Message-ID: <59d991c405071907482bb0689b@mail.gmail.com> Date: Tue, 19 Jul 2005 10:48:42 -0400 From: Christopher Petrilli Reply-To: Christopher Petrilli To: Tom Lane Subject: Re: Impact of checkpoint_segments under continual load conditions Cc: Vivek Khera , pgsql-performance@postgresql.org In-Reply-To: <16794.1121718743@sss.pgh.pa.us> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Content-Disposition: inline References: <59d991c4050717100874c08a86@mail.gmail.com> <59d991c405071811457ccdd3f1@mail.gmail.com> <16394.1121715156@sss.pgh.pa.us> <59d991c405071812342e290f57@mail.gmail.com> <16794.1121718743@sss.pgh.pa.us> X-Virus-Scanned: by amavisd-new at hub.org X-Spam-Status: No, hits=0.164 tagged_above=0 required=5 tests=AWL, RCVD_BY_IP X-Spam-Level: X-Archive-Number: 200507/280 X-Sequence-Number: 13521 On 7/18/05, Tom Lane wrote: > > The table has 15 columns, 5 indexes (character, inet and timestamp). > > No foreign keys. The only other thing running on the machine was the > > application actually DOING the benchmarking, written in Python > > (psycopg), but it was, according to top, using less than 1% of the > > CPU. It was just talking through a pipe to a psql prompt to do the > > COPY. >=20 > Sounds pretty plain-vanilla all right. >=20 > Are you in a position to try the same benchmark against CVS tip? > (The nightly snapshot tarball would be plenty close enough.) I'm > just wondering if the old bgwriter behavior of locking down the > bufmgr while it examined the ARC/2Q data structures is causing this... Tom, It looks like the CVS HEAD is definately "better," but not by a huge amount. The only difference is I wasn't run autovacuum in the background (default settings), but I don't think this explains it.=20 Here's a graph of the differences and density of behavior: http://blog.amber.org/diagrams/pgsql_copy_803_cvs.png I can provide the raw data. Each COPY was 500 rows. Note that fsync is turned off here. Maybe it'd be more stable with it turned on? Chris --=20 | Christopher Petrilli | petrilli@gmail.com