Re: pgbench -T isn't a hard cutoff.

From: Greg Smith <greg(at)2ndQuadrant(dot)com>
To: pgsql-bugs(at)postgresql(dot)org
Subject: Re: pgbench -T isn't a hard cutoff.
Date: 2011-08-29 03:22:54
Message-ID: 4E5B060E.1070604@2ndQuadrant.com
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On 08/26/2011 11:13 PM, mark wrote:
> Using the -T flag in pgbench I noticed that -T is a just a effort rather
> than a hard cut off.
> ...
> Expected behavior would be -T would mean a hard cut off.
>

If there's a hard cut-off, that means that partially completed
transactions are not included in the total. That produces less correct
results than the current scheme.

With the current behavior, worrying about partial amounts being ignored
isn't a problem. But there is the potential problem you report, which
is mainly a risk when pgbench is combined with a badly setup environment.

It's hard to justify making a change that will produce less accurate
results in the vast majority of cases, just to improve behavior in a
situation where useless results are coming out no matter what.

--
Greg Smith 2ndQuadrant US greg(at)2ndQuadrant(dot)com Baltimore, MD
PostgreSQL Training, Services, and 24x7 Support www.2ndQuadrant.us

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