Horton

Re: SIGQUIT handling, redux

Tom Lane <tgl@sss.pgh.pa.us>

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From: Tom Lane <tgl@sss.pgh.pa.us>
To: Andres Freund <andres@anarazel.de>
Cc: pgsql-hackers@lists.postgresql.org
Date: 2023-08-02T16:35:19Z
Lists: pgsql-hackers 
Andres Freund <andres@anarazel.de> writes:
> On 2020-09-11 11:52:55 -0400, Tom Lane wrote:
>> It's simple enough that maybe we could back-patch it, once it's
>> aged awhile in HEAD.  OTOH, given the lack of field reports of
>> trouble here, I'm not sure back-patching is worth the risk.

> FWIW, looking at collected stack traces in azure, there's a slow but steady
> stream of crashes below StartupPacketTimeoutHandler. ...
> Unsurprisingly just in versions before 14, where this change went in.
> I think that might be enough evidence for backpatching the commit? I've not
> heard of issues due to the checks in check_on_shmem_exit_lists_are_empty().

I'd be willing to take a look at this in a few weeks when $real_life
is a bit less demanding.  Right before minor releases would likely be
a bad idea anyway.

			regards, tom lane

Commits

  1. Log a message when resorting to SIGKILL during shutdown/crash recovery.

  2. Don't run atexit callbacks during signal exits from ProcessStartupPacket.

  3. Use _exit(2) for SIGQUIT during ProcessStartupPacket, too.

  4. Make archiver's SIGQUIT handler exit via _exit().