Date: Mon, 8 Apr 2019 07:48:04 -0700
From: Noah Misch <noah@leadboat.com>
To: Thomas Munro <thomas.munro@gmail.com>
Cc: Daniel Gustafsson <daniel@yesql.se>,
	Kyotaro HORIGUCHI <horiguchi.kyotaro@lab.ntt.co.jp>,
	"9erthalion6@gmail.com" <9erthalion6@gmail.com>,
	"sfrost@snowman.net" <sfrost@snowman.net>,
	"pgsql-hackers@postgresql.org" <pgsql-hackers@postgresql.org>
Subject: Re: [HACKERS] Weaker shmem interlock w/o postmaster.pid
Message-ID: <20190408144804.GA2389874@rfd.leadboat.com>
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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