Re: Performance degradation in commit ac1d794 - Mailing list pgsql-hackers

From Amit Kapila
Subject Re: Performance degradation in commit ac1d794
Date
Msg-id CAA4eK1+n_6U6Y7ug2zgE5VCzWQwQiJK8_nK1vPd8UnYWQaHaEw@mail.gmail.com
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In response to Re: Performance degradation in commit ac1d794  (Andres Freund <andres@anarazel.de>)
List pgsql-hackers
On Sat, Dec 26, 2015 at 5:41 PM, Andres Freund <andres@anarazel.de> wrote:
On 2015-12-26 12:22:48 +0100, Andres Freund wrote:
> > > 3) Replace the postmaster_alive_fds socketpair by some other signalling
> > >    mechanism. E.g. sending a procsignal to each backend, which sets the
> > >    latch and a special flag in the latch structure.
> >
> > And what would send the signal?  The entire point here is to notice the
> > situation where the postmaster has crashed.  It can *not* depend on the
> > postmaster taking some action.
>
> Ahem. Um. Look, over there --->
>
> I blame it on all the food.

A unportable and easy version of this, actually making sense this time,
would be to use prctl(PR_SET_PDEATHSIG, SIGQUIT). That'd send SIGQUIT to
backends whenever postmaster dies.  Obviously that's not portable
either - doing this for linux only wouldn't be all that kludgey tho.


There is a way to make backends exit in Windows as well by using
JobObjects and use limitFlags as JOB_OBJECT_LIMIT_KILL_ON_JOB_CLOSE
for JOBOBJECT_BASIC_LIMIT_INFORMATION.




With Regards,
Amit Kapila.
EnterpriseDB: http://www.enterprisedb.com

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