Horton

Re: New GUC to sample log queries

Alvaro Herrera <alvherre@2ndquadrant.com>

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From: Alvaro Herrera <alvherre@2ndquadrant.com>
To: Adrien Nayrat <adrien.nayrat@anayrat.info>
Cc: Thomas Munro <thomas.munro@enterprisedb.com>, Dmitry Dolgov <9erthalion6@gmail.com>, Tomas Vondra <tomas.vondra@2ndquadrant.com>, 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: 2018-11-29T21:48:50Z
Lists: pgsql-hackers 
Thanks!  I pushed this with two changes -- one was to reword the docs a
bit more, and the other was to compute in_sample only if it's going to
be used (when exceeded is true).  I hope this won't upset any compilers ...

I wonder if there's any sensible way to verify the behavior in an
automated fashion.  Who know what marvels we'd discover about the
reliability/uniformity of random() across platforms.

-- 
Álvaro Herrera                https://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services

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