From: Tom Lane <tgl@sss.pgh.pa.us>
To: Thomas Munro <thomas.munro@gmail.com>
cc: Michael Paquier <michael@paquier.xyz>, Noah Misch <noah@leadboat.com>,
        Jeff Davis <jdavis@postgresql.org>,
        Postgres hackers <pgsql-hackers@lists.postgresql.org>
Subject: Re: pgsql: Add contrib/pg_walinspect.
In-reply-to: <CA+hUKGLtswFk9ZO3WMOqnDkGs6dK5kCdQK9gxJm0N8gip5cpiA@mail.gmail.com>
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Comments: In-reply-to Thomas Munro <thomas.munro@gmail.com>
	message dated "Wed, 27 Apr 2022 12:06:30 +1200"
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Date: Tue, 26 Apr 2022 20:25:29 -0400
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Thomas Munro <thomas.munro@gmail.com> writes:
> I think it's a bug in pg_walinspect, so I'll move the discussion back
> here.  Here's one rather simple way to fix it, that has survived
> running the test a thousand times (using a recipe that failed for me
> quite soon, after 20-100 attempts or so; I never figured out how to
> get the 50% failure rate reported by Tom).

Not sure what we're doing differently, but plain "make check" in
contrib/pg_walinspect fails pretty consistently for me on gcc23.
I tried it again just now and got five failures in five attempts.

I then installed your patch and got the same failure, three times
out of three, so I don't think we're there yet.

Again, since I do have this problem in captivity, I'm happy
to spend some time poking at it.  But I could use a little
guidance where to poke, because I've not looked at any of
the WAL prefetch stuff.

			regards, tom lane