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Date: Sat, 14 Jan 2006 08:14:02 -0800 (PST)
From: Arne Woerner <arne_woerner@yahoo.com>
To: Ivan Voras <ivoras@fer.hr>, freebsd-performance@freebsd.org,
	slawek.zak@gmail.com
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Subject: Re: Horrible PostgreSQL performance with NFS
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--- Ivan Voras <ivoras@fer.hr> wrote:
> Arne Woerner wrote:
> > But why does switching from local disc
> > to NFS makes the PostgreSQL performance
> > so bad?
> 
> A wild guess/try: does file locking work
> properly with NFS and the filer?
>
I would recommend the following test in order to answer that
question:

Executing the shell script in appendix A of this email will test,
if locking works, and how fast it is:
% time ./lck-tst.sh </path/to/local-fs/file>
% time ./lck-tst.sh </path/to/NFS/file>

-Arne

appendix A: the script lck-tst.sh
#!/bin/sh

lockf -k $1 sleep 10 &
sleep 3
lockf -k -s -t 0 $1 echo BAD || echo GOOD
wait

sts=`date +%s`
i=0
while [ $i -lt 2000 ]; do
  i=`expr $i + 1`
  lockf -k $1 sleep 0 &
done
expr `date +%s` - $sts


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