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

From Andres Freund
Subject Re: Performance degradation in commit ac1d794
Date
Msg-id 20151226121114.x3mh4v33flkxnqgl@alap3.anarazel.de
Whole thread Raw
In response to Re: Performance degradation in commit ac1d794  (Andres Freund <andres@anarazel.de>)
Responses Re: Performance degradation in commit ac1d794  (Tom Lane <tgl@sss.pgh.pa.us>)
Re: Performance degradation in commit ac1d794  (Amit Kapila <amit.kapila16@gmail.com>)
List pgsql-hackers
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.



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