From: Michael Paquier <michael@paquier.xyz>
To: Andres Freund <andres@anarazel.de>
Cc: Andrey Borodin <x4mmm@yandex-team.ru>
Cc: Alvaro Herrera <alvherre@alvh.no-ip.org>
Cc: Robert Haas <robertmhaas@gmail.com>
Cc: Peter Geoghegan <pg@bowt.ie>
Cc: Петър Славов <pet.slavov@gmail.com>
Cc: PostgreSQL mailing lists <pgsql-bugs@lists.postgresql.org>
Subject: Re: BUG #17485: Records missing from Primary Key index when doing REINDEX INDEX CONCURRENTLY
Date: Tue, 31 May 2022 10:45:04 +0900
Message-ID: <YpVzILvc0Uowuir8@paquier.xyz> (raw)
In-Reply-To: <20220530191004.oc7kugjyn4isghti@alap3.anarazel.de>
References: <CA+TgmoYP7BnHXTEoJRUnOuie2J05Qo8ti5mnE2u-1c4Hk+8zJw@mail.gmail.com>
<202205251643.2py5jjpaw7wy@alvherre.pgsql>
<20220527231332.jwvrx6b3ytzt5snv@alap3.anarazel.de>
<A4F69174-AEC8-4108-BD32-CF201E56AF3E@yandex-team.ru>
<20220528070219.kbj527dx2sxmuomi@alap3.anarazel.de>
<4B1BA5BF-37EC-4EE7-AB3B-4C4D95A8059A@yandex-team.ru>
<20220528193413.cvhno3ky4tikuiqo@alap3.anarazel.de>
<YpRqEBsFui+lzGj9@paquier.xyz>
<20220530191004.oc7kugjyn4isghti@alap3.anarazel.de>
On Mon, May 30, 2022 at 12:10:04PM -0700, Andres Freund wrote:
> I think it's ok if we have a heuristic test for this kind of thing. It
> sometimes can even be good, because it means we'll get different schedulings
> over time, hitting "unknown" bugs.
Yeah, the tricky part is how to parametize that to be cheap, still
useful. Having a larger number of attributes makes the particular
problem of this thread easier to hit because it enlarges the
validation window in the concurrent build, and generating such dummy
data with a simple schema should be quick enough, but I would not
accept in the tree a test that takes ~5s to run without a rather good
hit rate. For this particular issue, I would say that something able
to fail up to 20%~25% of the time for a short run-time would be quite
decent, actually, even if that sounds low in a single run because the
odds of detecting one failure increase a "lot" after a few repeated
runs.
On my own laptop, the original test of the reporter takes up to 3~4s
to reproduce the issue, for example, all the time, so that's good :)
--
Michael
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To: pgsql-bugs@postgresql.org
Cc: michael@paquier.xyz, andres@anarazel.de, x4mmm@yandex-team.ru, alvherre@alvh.no-ip.org, robertmhaas@gmail.com, pg@bowt.ie, pet.slavov@gmail.com, pgsql-bugs@lists.postgresql.org
Subject: Re: BUG #17485: Records missing from Primary Key index when doing REINDEX INDEX CONCURRENTLY
In-Reply-To: <YpVzILvc0Uowuir8@paquier.xyz>
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