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Subject: Re: Sample rate added to pg_stat_statements
From: "Andrey M. Borodin" <x4mmm@yandex-team.ru>
In-Reply-To: <52e5e3aa-066a-4daf-8d65-77c34a2f0d98@tantorlabs.com>
Date: Mon, 6 Jan 2025 20:57:40 +0500
Cc: Alexander Korotkov <aekorotkov@gmail.com>,
 Michael Paquier <michael@paquier.xyz>,
 Greg Sabino Mullane <htamfids@gmail.com>,
 pgsql-hackers <pgsql-hackers@postgresql.org>
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To: Ilia Evdokimov <ilya.evdokimov@tantorlabs.com>
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> On 6 Jan 2025, at 15:50, Ilia Evdokimov =
<ilya.evdokimov@tantorlabs.com> wrote:
>=20
> Any suggestions for improvements?

The patch looks good to me, just a few nits.

0. Perhaps, we could have a test for edge values of 0 and 1. I do not =
insist, just an idea to think about.

1. This code seems a little different from your patch. It is trying to =
avoid engaging PRNG. I'm not sure it's a good idea, but still. Also, it =
uses "<=3D", not "<".

    xact_is_sampled =3D log_xact_sample_rate !=3D 0 &&
(log_xact_sample_rate =3D=3D 1 ||
pg_prng_double(&pg_global_prng_state) <=3D log_xact_sample_rate);

Thanks!


Best regards, Andrey Borodin.=