Horton

Re: [PATCH] Introduce array_shuffle() and array_sample()

Martin Kalcher <martin.kalcher@aboutsource.net>

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From: Martin Kalcher <martin.kalcher@aboutsource.net>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: Andres Freund <andres@anarazel.de>, Fabien COELHO <coelho@cri.ensmp.fr>, Dean Rasheed <dean.a.rasheed@gmail.com>, Robert Haas <robertmhaas@gmail.com>, Andrew Dunstan <andrew@dunslane.net>, John Naylor <john.naylor@enterprisedb.com>, Thomas Munro <thomas.munro@gmail.com>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Date: 2022-09-28T10:40:31Z
Lists: pgsql-hackers, pgsql-general 
Am 26.09.22 um 22:16 schrieb Tom Lane:
> 
> With our current PRNG infrastructure it doesn't cost much to have
> a separate PRNG for every purpose.  I don't object to having
> array_shuffle() and array_sample() share one PRNG, but I don't
> think it should go much further than that.
> 

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?

Martin

Commits

  1. Add array_sample() and array_shuffle() functions.

  2. Use a separate random seed for SQL random()/setseed() functions.