Re: recovery is stuck when children are not processing SIGQUIT from previous crash

Marko Kreen <markokr@gmail.com>

From: Marko Kreen <markokr@gmail.com>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: Peter Eisentraut <peter_e@gmx.net>, pgsql-admin@postgresql.org
Date: 2009-11-12T20:37:03Z
Lists: pgsql-hackers
On 11/12/09, Tom Lane <tgl@sss.pgh.pa.us> wrote:
> Marko Kreen <markokr@gmail.com> writes:
> > You talked about blocking in quickdie(), but you'd need
>  > to block in elog().
>
>  I'm not really particularly worried about that case.  By that logic,
>  we could not use quickdie at all, because any part of the system
>  might be doing something that wouldn't survive being interrupted.

Not really - we'd need to care only about parts that quickdie()
(or any other signal handler) wants to use.  Which basically means
elog() only.

OK, full elog() is a beast, but why would SIGQUIT handler need full
elog()?  How about we export minimal log-writing function and make
that signal-safe - that is, drop message if already active.  This
will excange potential crash/deadlock with lost msg which seems
slightly better behaviour.

-- 
marko