| From: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
|---|---|
| To: | Andres Freund <andres(at)anarazel(dot)de> |
| Cc: | Fabien COELHO <coelho(at)cri(dot)ensmp(dot)fr>, PostgreSQL Developers <pgsql-hackers(at)postgresql(dot)org>, Robert Haas <robertmhaas(at)gmail(dot)com> |
| Subject: | Re: pgbench randomness initialization |
| Date: | 2016-04-07 13:46:27 |
| Message-ID: | 1589.1460036787@sss.pgh.pa.us |
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| Lists: | pgsql-hackers |
Andres Freund <andres(at)anarazel(dot)de> writes:
> On 2016-04-07 12:25:58 +0200, Fabien COELHO wrote:
>> So I have no mathematical doubt that changing the seed is the right default
>> setting, thus I think that the current behavior is fine. However I'm okay if
>> someone wants to control the randomness for some reason (maybe having "less
>> sure" results, but quickly), so it could be allowed somehow.
> There might be some statistics arguments, but I think they're pretty
> ignoring reality.
Sorry, but I think Fabien is right and you are wrong. There is no
point in having randomness in there at all if the thing is constrained
to generate the same "random" sequence every time.
I don't object to having an option to force the initial seed, but
it should not be the default, and it most certainly should not be
the only behavior.
regards, tom lane
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