From: Steve Poe <spoe@sfnet.cc>
To: Thomas F.O'Connell <tfo@sitening.com>
Cc: PgSQL - Performance <pgsql-performance@postgresql.org>
Subject: Re: pgbench Comparison of 7.4.7 to 8.0.2
Date: Sun, 24 Apr 2005 23:58:16 -0700
Message-ID: <426C9508.8030902@sfnet.cc> (raw)
In-Reply-To: <b4a298793e5eee60fb12a725197d5c42@sitening.com>
References: <2784476415a96bb0912ebca41edb3d84@sitening.com>
<6865.1113600214@sss.pgh.pa.us>
<b4a298793e5eee60fb12a725197d5c42@sitening.com>
>There was some interesting oscillation behavior in both version of
postgres that occurred with 25 >clients and 1000 transactions at a
scaling factor of 100. This was repeatable with the distribution
>version of pgbench run iteratively from the command line. I'm not sure
how to explain this.
Tom,
When you see these oscillations, do they occur after so many generated
results? Some oscillation is normal, in my opinion, from 10-15% of the
performance is noise-related.
The key is to tune the server that you either 1) minimize the
oscillation and/or 2)increase your overall performance above the 10-15%
baseline, and 3) find out what the mean and standard deviation between
all your results.
If your results are within that range, this maybe "normal". I follow-up
with you later on what I do.
Steve Poe
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To: pgsql-performance@postgresql.org
Cc: spoe@sfnet.cc, tfo@sitening.com
Subject: Re: pgbench Comparison of 7.4.7 to 8.0.2
In-Reply-To: <426C9508.8030902@sfnet.cc>
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