From: Tom Lane <tgl@sss.pgh.pa.us>
To: Thomas Munro <thomas.munro@gmail.com>
Cc: pgsql-committers <pgsql-committers@lists.postgresql.org>
Subject: Re: pgsql: TAP tests: check for postmaster.pid anyway when "pg_ctl start" f
Date: Thu, 20 Jan 2022 09:32:16 -0500
Message-ID: <867290.1642689136@sss.pgh.pa.us> (raw)
In-Reply-To: <855583.1642687119@sss.pgh.pa.us>
References: <E1nAIWI-0006et-HW@gemulon.postgresql.org>
<CA+hUKGKV6fOHvfiPt8=dOKzvswjAyLoFoJF1iQXMNpi7+hD1JQ@mail.gmail.com>
<855583.1642687119@sss.pgh.pa.us>
I wrote:
> Hmm. I think the problem is that poll_start() thinks it can just call
> start() a second time after a failure. If it wasn't a true failure
> but a timeout, then _pid is now set and the second call complains.
Oh, wait --- the case that is failing is after 017_shm.pl has
intentionally kill -9'd a postmaster, so that its pidfile is
left behind. The next attempted start fails on shmem id
conflict, but it doesn't remove the old pidfile, and then
the code I added to sub start erroneously picks that up
as a live postmaster PID.
Seems like we need to do 'kill 0' on the PID we get from
the file to verify that there's really a postmaster there.
(I wonder how well that works on Windows? perlport claims
it does, but ...)
I fear I still don't have the whole story though because
per this theory it should fail everywhere, yet it doesn't.
regards, tom lane
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To: pgsql-committers@postgresql.org
Cc: tgl@sss.pgh.pa.us, thomas.munro@gmail.com, pgsql-committers@lists.postgresql.org
Subject: Re: pgsql: TAP tests: check for postmaster.pid anyway when "pg_ctl start" f
In-Reply-To: <867290.1642689136@sss.pgh.pa.us>
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