Re: stray SIGALRM

Andres Freund <andres(at)2ndquadrant(dot)com> writes:
> On 2013-06-15 11:29:45 -0400, Tom Lane wrote:
>> Hmm. Personally I'd rather go in the other direction:
>> http://www.postgresql.org/message-id/12819.1183306286@sss.pgh.pa.us

> I am not actually objecting that reasoning, I think it would be rather
> useful to get there.
> But I don't think it's realistic to do that at this point in the
> 9.3 cycle. It seems like we would fight bugs around that for quite a
> while. We have a large number of syscall sites where we don't retry on
> EINTR/EAGAIN. And, as you note, that's not even talking about third
> party code.

Yeah, it's the issue of third-party code within the backend (perl,
python, etc etc etc etc) that really makes complete EINTR-proofing seem
a bit impractical.

Back in the day I was also worried about platforms that didn't have
SA_RESTART, but that's probably pretty much the empty set by now (is
anyone aware of a modern platform on which configure fails to set
HAVE_POSIX_SIGNALS?). Also, our switch to latches for sleeping purposes
should have ameliorated the issue of signals failing to wake processes
when we wanted them to.

Let's turn on SA_RESTART for SIGALRM in HEAD and 9.3 and see what beta
testing says.

regards, tom lane