From: Tom Lane <tgl@sss.pgh.pa.us>
To: Peter Geoghegan <pg@bowt.ie>
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>
Subject: Re: random() (was Re: New GUC to sample log queries)
In-reply-to: 
 <CAH2-WznB-bx=AYpkWiRps1yy6QQaV8N=JWQSQvJM+fG4UZi4Og@mail.gmail.com>
References: <20181129214850.kiq6mvofsgplqjdr@alvherre.pgsql>
 <3859.1545849900@sss.pgh.pa.us>
 <CAH2-Wzk1Wa4TcrdOQv=eknY_NWyr2bTKf3rFtWPu06-V6LhE6A@mail.gmail.com>
 <5659.1545852666@sss.pgh.pa.us>
 <CAH2-Wz=MGrJ5G-FtKVDnWzVuj6P2imQ3QTydex2fDgQGHXfdew@mail.gmail.com>
 <CAH2-WznB-bx=AYpkWiRps1yy6QQaV8N=JWQSQvJM+fG4UZi4Og@mail.gmail.com>
Comments: In-reply-to Peter Geoghegan <pg@bowt.ie>
	message dated "Wed, 26 Dec 2018 11:56:04 -0800"
MIME-Version: 1.0
Content-Type: text/plain; charset="us-ascii"
Content-ID: <14046.1545855555.1@sss.pgh.pa.us>
Date: Wed, 26 Dec 2018 15:19:15 -0500
Message-ID: <14047.1545855555@sss.pgh.pa.us>
Precedence: bulk

Peter Geoghegan <pg@bowt.ie> writes:
> I'm beginning to think that the technique that I came up with to make
> "getting tired" deterministic ought to be supporting as a debugging
> option if we're to do away with internal use of the generic/seedable
> backend PRNG.

I have no objection to providing such a thing as a debug option; I just
don't want it to be reachable from SQL (at least not without pieces
that aren't there normally, e.g. a loadable C function).

Replacing random() might actually make that easier not harder, since
we'd have more control over what happens when.

			regards, tom lane