From: Chris Mair <list@1006.org>
To: Alvaro Herrera <alvherre@commandprompt.com>
Cc: Luke Lonergan <llonergan@greenplum.com>
Cc: pgsql-performance@postgresql.org, markir@paradise.net.nz, Josh Berkus <josh@agliodbs.com>
Subject: Re: bad performance on Solaris 10
Date: Thu, 06 Apr 2006 01:13:55 +0200
Message-ID: <1144278835.5133.11.camel@dell.home.lan> (raw)
In-Reply-To: <20060405214824.GB13673@surnet.cl>
References: <1144272685.4562.43.camel@dell.home.lan>
<C059874E.20ECE%llonergan@greenplum.com>
<20060405214824.GB13673@surnet.cl>
> > > 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 ;)
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To: pgsql-performance@postgresql.org
Cc: list@1006.org, alvherre@commandprompt.com, llonergan@greenplum.com, josh@agliodbs.com
Subject: Re: bad performance on Solaris 10
In-Reply-To: <1144278835.5133.11.camel@dell.home.lan>
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