Re: pgbench progress report improvements - split 2

On Tue, Sep 24, 2013 at 08:42:15PM +0200, Fabien COELHO wrote:
>> meet all those goals simultaneously with simpler code, can we not?
>>
>> int64 wait = (int64) (throttle_delay *
>> Min(7.0, -log(1 - pg_erand48(thread->random_state))));
>
> If you truncate roughly the multipler, as it is done here with "min", you
> necessarily create a bias, my random guess would be a 0.5% under
> estimation, but maybe it is more... Thus you would have to compute and
> the correcting factor as well. Its computation is a little bit less easy
> than with the quantized formula where I just used a simple SUM, and you
> have to really do the maths here. So I would keep the simple solution,
> but it is fine with me if you do the maths!

Ah, true; I guess each approach has different advantages. I've committed your
latest version.

--
Noah Misch
EnterpriseDB http://www.enterprisedb.com