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 E13F711F676E for ; Wed, 5 Apr 2006 20:33:10 -0300 (ADT) Received: from postgresql.org ([200.46.204.71]) by localhost (av.hub.org [200.46.204.144]) (amavisd-new, port 10024) with ESMTP id 98783-05 for ; Wed, 5 Apr 2006 20:33:10 -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 36AF111F6724 for ; Wed, 5 Apr 2006 20:33:07 -0300 (ADT) Received: from dell.home.lan (host14-128.pool8251.interbusiness.it [82.51.128.14]) (authenticated (0 bits)) by my.endian.it (8.11.6/8.11.6) with ESMTP id k360Zvr18005 for ; Thu, 6 Apr 2006 02:35:57 +0200 Subject: Re: bad performance on Solaris 10 From: Chris Mair To: pgsql-performance@postgresql.org In-Reply-To: <1144272685.4562.43.camel@dell.home.lan> References: <1144111178.3723.80.camel@dell.home.lan> <1144272685.4562.43.camel@dell.home.lan> Content-Type: text/plain Date: Thu, 06 Apr 2006 01:33:07 +0200 Message-Id: <1144279987.5133.22.camel@dell.home.lan> Mime-Version: 1.0 X-Mailer: Evolution 2.0.2 (2.0.2-22) Content-Transfer-Encoding: 7bit X-Virus-Scanned: by amavisd-new at hub.org X-Spam-Status: No, score=0.09 required=5 tests=[AWL=0.090] X-Spam-Score: 0.09 X-Spam-Level: X-Archive-Number: 200604/81 X-Sequence-Number: 18165 appears this didn't make it to the list... resending to the list directly... --- > > > Doing what http://blogs.sun.com/roller/page/jkshah suggests: > > > wal_sync_method = fsync (unchanged) > > > wal_buffers = 128 (was 8) > > > checkpoint_segments = 128 (was 3) > > > bgwriter_all_percent = 0 (was 0.333) > > > bgwriter_all_maxpages = 0 (was 5) > > > and leaving everything else default (solarispackages from pgfoundry) > > > increased performance ~ 7 times! Ok, so I could quite believe my own benchmarks and I decided to do a fresh initdb and retry everything. At first it looked like I coudn't reproduce the speed up I just saw. Then I realized it was the wal_sync_method = fsync line that makes all the difference! Normally parameters that are commented are default values, but for wal_sync_method it actually says (note the comment): wal_sync_method = fsync # the default is the first option # supported by the operating system: # open_datasync # fdatasync # fsync # fsync_writethrough # open_sync So Im my last mail I drew the wrong conclusion, because i didn't comment wal_sync_method to double check. To the point: the default wal_sync_method choosen on Solaris 10 appears to be a very bad one - for me, picking fsync increases performance ~ times 7, all other parameters unchanged! Would it be a good idea to change this in the default install? Bye, Chris. PS: yes I did a fresh initdb again to double check ;)