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!


Thomas F. O'Connell
Co-Founder, Information Architect
Sitening, LLC

Strategic Open Source: Open Your iâ„¢
110 30th Avenue North, Suite 6
Nashville, TN 37203-6320

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.


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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