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Subject: Re: bad performance on Solaris 10
From: Chris Mair <list@1006.org>
To: Mark Kirkwood <markir@paradise.net.nz>
Cc: pgsql-performance@postgresql.org, josh@agliodbs.com,
	llonergan@greenplum.com
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Date: Thu, 06 Apr 2006 01:29:40 +0200
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> > I've done a few tests.
> > 
> > Remounting the fs where $PGDATA lives with "forcedirectio"
> > (together with logging, that is default) did not help
> > (if not harm...) performance.
> > 
> >
> 
> Sure - forcedirectio on the entire $PGDATA is a definite loss, you only 
> want it on $PGDATA/pg_xlog. The usual way this is accomplished is by 
> making a separate filsystem for pg_xlog and symlinking from $PGDATA.
> 
> Did you try the other option of remounting the fs for $PGDATA without 
> logging or forcedirectio?

not yet, I'm not on the final disk set yet.

when I get there I'll have two separate filesystems for pg_xlog and base
and will try what you suggest.

(but note the other mail about wal_sync_method = fsync)

bye, chris.