Re: [PATCH] pgbench --throttle (submission 7 - with lag measurement)

Fabien,

> Hello again Tatsuo,
>
>> For your information, included is the patch against git master head to
>> implement the lag in a way what I proposed. With the patch, I get more
>> consistent number on Linux (and Mac OS X).
>
> I must disagree with your proposal: At least, it does not provide the
> information I want, but another one.
>
> ISTM that this patch measures the lag which is due to pgbench thread
> coming around to deal with a transaction after sleeping. I would
> expect that to be quite small most of the time, so I agree that it
> must be reassuringly consistent.
>
> However it does not provide the information I want, which is the
> measure of the health of pgbench with respect to the stochastic
> process scheduled transactions.
>
> Basically you propose a partial lag measure, which will be smaller,
> but which does not tell whether pgbench is able to follow the
> schedule, which is the information I find useful in this context to
> appreciate if the throttling is going well.

I don't care what kind of measurement is provided by pgbench. However
I *do* care about what the measurement means is clearly described in
the doc as a committer. I think current measurement method will give
enough confusion if it's not provided with detailed explanation. Could
you please provide doc updatation?
--
Tatsuo Ishii
SRA OSS, Inc. Japan
English: http://www.sraoss.co.jp/index_en.php
Japanese: http://www.sraoss.co.jp