Re: pgbench randomness initialization
Tom Lane <tgl@sss.pgh.pa.us>
From: Tom Lane <tgl@sss.pgh.pa.us>
To: Andres Freund <andres@anarazel.de>
Cc: Fabien COELHO <coelho@cri.ensmp.fr>,
PostgreSQL Developers <pgsql-hackers@postgresql.org>,
Robert Haas <robertmhaas@gmail.com>
Date: 2016-04-07T13:46:27Z
Lists: pgsql-hackers
Andres Freund <andres@anarazel.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
Commits
-
Set random seed for pgbench.
- 64f85894ad27 11.0 landed
-
Fix pgbench TAP test to work in VPATH builds.
- e94f2bc809a0 11.0 landed