From: Carlos Moreno <morenopg@mochima.com>
To: pgsql-performance@postgresql.org
Subject: Re: "Mysterious" issues with newly installed 8.3
Date: Mon, 13 Oct 2008 10:55:23 -0400
Message-ID: <48F3615B.4050705@mochima.com> (raw)
In-Reply-To: <Pine.GSO.4.64.0810100345010.26609@westnet.com>
References: <48EE98FE.60100@mochima.com>
<a1ec7d000810091734k60cee7d7qb95470936ad461c1@mail.gmail.com>
<Pine.GSO.4.64.0810100345010.26609@westnet.com>
Thanks Greg and others for your replies,
> This is really something to watch out for. One quick thing first
> though: what frequency does the CPU on the new server show when you
> look at /proc/cpuinfo? If you see "cpu MHz: 1000.00"
It was like that in the initial setup --- I just disabled the cpuspeed
service (service cpuspeed stop; chkconfig cpuspeed off ), and now
it shows the full 2600MHz at all times (the installation of PG was
done after this change)
> Another really handy way to gauge memory speed on Linux, if there are
> similar kernels installed on each system like your case, is to use
> "hdparm -T".
Great tip! I was familiar with the -T switch, but was not clear on the
notion that the figure tells you that much about the overall memory
performance!
Anyway, I checked on both, and the new system is slightly superior
(around 2200 for the new, around 1900 for the old one) --- a bit below
the figure you mention you'd expect (2500 --- though that was for a
2.8GHz Opteron, presumably with faster FSB and faster memory??)
I guess my logical next step is what was suggested by Scott --- install
8.2.4 and repeat the same tests with this one; that should give me
interesting information.
Anyway, if I find something interesting or puzzling, I would post again
with the results of those tests.
Thanks again for the valuable advice and comments!
Carlos
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To: pgsql-performance@postgresql.org
Cc: morenopg@mochima.com
Subject: Re: "Mysterious" issues with newly installed 8.3
In-Reply-To: <48F3615B.4050705@mochima.com>
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