X-Original-To: pgsql-performance-postgresql.org@localhost.postgresql.org Received: from localhost (mx1.hub.org [200.46.208.251]) by postgresql.org (Postfix) with ESMTP id ADC1D9FA293 for ; Thu, 18 May 2006 09:44:56 -0300 (ADT) Received: from postgresql.org ([200.46.204.71]) by localhost (mx1.hub.org [200.46.208.251]) (amavisd-new, port 10024) with ESMTP id 27044-04 for ; Thu, 18 May 2006 09:44:45 -0300 (ADT) X-Greylist: from auto-whitelisted by SQLgrey- Received: from my.endian.it (unknown [62.146.87.34]) by postgresql.org (Postfix) with ESMTP id BF4E59F9C18 for ; Thu, 18 May 2006 09:44:43 -0300 (ADT) Received: from dell.home.lan (host45-104.pool875.interbusiness.it [87.5.104.45]) (authenticated (0 bits)) by my.endian.it (8.11.6/8.11.6) with ESMTP id k4ICn3104140; Thu, 18 May 2006 14:49:03 +0200 Subject: Re: Benchmarck PostgreSQL 8.1.4 MySQL 5.0.20 and Oracle From: Chris Mair To: Olivier Andreotti Cc: pgsql-performance@postgresql.org In-Reply-To: References: <1147947373.7943.35.camel@dell.home.lan> Content-Type: text/plain Date: Thu, 18 May 2006 14:44:40 +0200 Message-Id: <1147956280.9324.7.camel@dell.home.lan> Mime-Version: 1.0 X-Mailer: Evolution 2.0.2 (2.0.2-27) Content-Transfer-Encoding: 7bit X-Virus-Scanned: Maia Mailguard 1.0.1 X-Archive-Number: 200605/385 X-Sequence-Number: 19172 > > Could you give us some more infos about the box' performance while you > > run the PG benchmark? A few minutes output of "vmstat 10" maybe? What > > does "top" say? > > > > Here, an extract from the vmstat 3 during the test, you can see that > my problem is probably a very high disk usage (write and read). > > procs -----------memory---------- ---swap-- -----io---- --system-- ----cpu---- > r b swpd free buff cache si so bi bo in cs us sy id wa > 0 11 92 128344 9224 2428432 0 0 287 9691 2227 685 4 3 0 93 > [...] Yes, as is the case most of the time, disk I/O is the bottleneck here... I'd look into everything disk releated here... > > How are you using the 3 disks? Did you split pg_xlog and the database > > on different disks or not? > > > > Data are on disk 1 et 2. Index on disk 3. Perhaps i'm wrong but fsync > = off, pg_xlog are running with that ? Yes, pg_xlog ist also used with fsync=off. you might gain quite some performance if you can manage to put pg_xlog on its own disk (just symlink the directory). Anyway, as others have pointed out, consider that with fsync = off you're loosing the "unbreakability" in case of power failures / os crashes etc. > > Can you say something about the clients? Do they run over network from > > other hosts? What language/bindings do they use? > > > > Client is another server from the same network. Clients are connected > with JDBC connector. ok, don't know about that one.. > > When they do inserts, are the inserts bundled or are there > > single insert transactions? Are the statements prepared? > I use prepared statements for all requests. Each transaction is about > 5-45 requests. sounds ok, could be even more bundled together if the application is compatible with that. Bye, Chris.