| From: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
|---|---|
| To: | Fabien COELHO <coelho(at)cri(dot)ensmp(dot)fr> |
| Cc: | Martin Kalcher <martin(dot)kalcher(at)aboutsource(dot)net>, Andres Freund <andres(at)anarazel(dot)de>, Dean Rasheed <dean(dot)a(dot)rasheed(at)gmail(dot)com>, Robert Haas <robertmhaas(at)gmail(dot)com>, Andrew Dunstan <andrew(at)dunslane(dot)net>, John Naylor <john(dot)naylor(at)enterprisedb(dot)com>, Thomas Munro <thomas(dot)munro(at)gmail(dot)com>, PostgreSQL Hackers <pgsql-hackers(at)lists(dot)postgresql(dot)org> |
| Subject: | Re: [PATCH] Introduce array_shuffle() and array_sample() |
| Date: | 2022-09-28 14:18:45 |
| Message-ID: | 3943591.1664374725@sss.pgh.pa.us |
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| Lists: | pgsql-general pgsql-hackers |
Fabien COELHO <coelho(at)cri(dot)ensmp(dot)fr> writes:
>> Thanks for your thoughts, Tom. I have a couple of questions. Should we
>> introduce a new seed function for the new PRNG state, used by array_shuffle()
>> and array_sample()? What would be a good name? Or should those functions use
>> pg_global_prng_state? Is it safe to assume, that pg_global_prng_state is
>> seeded?
> I'd suggest to use the existing global state. The global state should be
> seeded at the process start, AFAIKR.
It is seeded at process start, yes. If you don't feel a need for
user control over the sequence used by these functions, then using
pg_global_prng_state is fine. (Basically the point to be made
here is that we need to keep a tight rein on what can be affected
by setseed().)
regards, tom lane
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