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: Mon, 25 Apr 2005 10:18:23 -0700
Message-ID: <426D265F.9080902@sfnet.cc> (raw)
In-Reply-To: <02c5560a910870da3637b6ff791e3a80@sitening.com>
References: <2784476415a96bb0912ebca41edb3d84@sitening.com>
<6865.1113600214@sss.pgh.pa.us>
<b4a298793e5eee60fb12a725197d5c42@sitening.com>
<426C9508.8030902@sfnet.cc>
<02c5560a910870da3637b6ff791e3a80@sitening.com>
Tom,
Just a quick thought: after each run/sample of pgbench, I drop the
database and recreate it. When I don't my results become more skewed.
Steve Poe
Thomas F.O'Connell wrote:
> Interesting. I should've included standard deviation in my pgbench
> iteration patch. Maybe I'll go back and do that.
>
> I was seeing oscillation across the majority of iterations in the 25
> clients/1000 transaction runs on both database versions.
>
> I've got my box specs and configuration files posted. If you see
> anything obvious about the tuning parameters that should be tweaked,
> please let me know.
>
> Thanks for the feedback!
>
> -tfo
>
> --
> Thomas F. O'Connell
> Co-Founder, Information Architect
> Sitening, LLC
>
> Strategic Open Source: Open Your iâ„¢
>
> http://www.sitening.com/
> 110 30th Avenue North, Suite 6
> Nashville, TN 37203-6320
> 615-260-0005
>
> On Apr 25, 2005, at 1:58 AM, Steve Poe wrote:
>
>> >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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Cc: spoe@sfnet.cc, tfo@sitening.com
Subject: Re: pgbench Comparison of 7.4.7 to 8.0.2
In-Reply-To: <426D265F.9080902@sfnet.cc>
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