Re: [HACKERS] Weaker shmem interlock w/o postmaster.pid

On Mon, Apr 08, 2019 at 08:07:28PM +1200, Thomas Munro wrote:
> On Mon, Apr 8, 2019 at 6:42 PM Noah Misch <noah@leadboat.com> wrote:
> > - lorikeet's FailedAssertion("!(vmq->mq_sender == ((void *)0))" looked
> >   suspicious, but this happened six other times in the past year[2], always on
> >   v10 lorikeet.
> 
> It happens on v11 too:
> 
> https://buildfarm.postgresql.org/cgi-bin/show_log.pl?nm=lorikeet&dt=2018-09-25%2010%3A06%3A31
> 
> The text changed slightly because we dropped an unnecessary extra
> pointer-to-volatile:
> 
> FailedAssertion("!(mq->mq_sender == ((void *)0))"
> 
> So either two workers started with the same parallel worker number, or
> something unexpectedly overwrote the shm_mq struct?

Ahh.  In that case, it's a duplicate of
https://postgr.es/m/flat/136712b0-0619-5619-4634-0f0286acaef7%402ndQuadrant.com