Horton

Re: random() (was Re: New GUC to sample log queries)

Peter Geoghegan <pg@bowt.ie>

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From: Peter Geoghegan <pg@bowt.ie>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: Alvaro Herrera <alvherre@2ndquadrant.com>, Adrien Nayrat <adrien.nayrat@anayrat.info>, Thomas Munro <thomas.munro@enterprisedb.com>, Dmitry Dolgov <9erthalion6@gmail.com>, Tomas Vondra <tomas.vondra@2ndquadrant.com>, Vik Fearing <vik.fearing@2ndquadrant.com>, Robert Haas <robertmhaas@gmail.com>, Michael Paquier <michael@paquier.xyz>, David Rowley <david.rowley@2ndquadrant.com>, Pg Hackers <pgsql-hackers@postgresql.org>
Date: 2018-12-26T20:27:50Z
Lists: pgsql-hackers 
On Wed, Dec 26, 2018 at 12:19 PM Tom Lane <tgl@sss.pgh.pa.us> wrote:
> Replacing random() might actually make that easier not harder, since
> we'd have more control over what happens when.

That does seem useful. I'm in favor. But why does the function to seed
the internal PRNG have to be loadable? Can't it just be
superuser-only?

-- 
Peter Geoghegan

Commits

  1. Use pg_strong_random() to select each server process's random seed.

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

  3. Marginal performance hacking in erand48.c.

  4. Fix latent problem with pg_jrand48().

  5. Silence compiler warning

  6. Add log_statement_sample_rate parameter