From: Tom Lane <tgl@sss.pgh.pa.us>
To: Noah Misch <noah@leadboat.com>
cc: pgsql-hackers@lists.postgresql.org
Subject: Re: Unexpected "shared memory block is still in use"
In-reply-to: <20190509055414.GB1066859@rfd.leadboat.com>
References: <22224.1557340366@sss.pgh.pa.us>
 <20190509055414.GB1066859@rfd.leadboat.com>
Comments: In-reply-to Noah Misch <noah@leadboat.com>
	message dated "Wed, 08 May 2019 22:54:14 -0700"
MIME-Version: 1.0
Content-Type: text/plain; charset="us-ascii"
Content-ID: <2662.1557409654.1@sss.pgh.pa.us>
Content-Transfer-Encoding: quoted-printable
Date: Thu, 09 May 2019 09:47:34 -0400
Message-ID: <2663.1557409654@sss.pgh.pa.us>
Precedence: bulk

Noah Misch <noah@leadboat.com> writes:
> On Wed, May 08, 2019 at 02:32:46PM -0400, Tom Lane wrote:
>> Just now, while running a parallel check-world on HEAD according to the
>> same script I've been using for quite some time, one of the TAP tests
>> died during initdb:
>> performing post-bootstrap initialization ... 2019-05-08 13:59:19.963 ED=
T [18351] FATAL:  pre-existing shared memory block (key 5440004, ID 173447=
5802) is still in use

> The odds are very high that you would not have gotten that error before =
that
> commit.  But if the cause matches your guess, it's not something wrong w=
ith
> the commit ...

Fair point.

> What OS, OS version, and filesystem?

Up-to-date RHEL6 (kernel 2.6.32-754.12.1.el6.x86_64), ext4 over LVM
on spinning rust with an LSI MegaRAID controller in front of it.

Since complaining, I've done half a dozen more parallel check-worlds
without issue, so the error was and still is rare.  This matches the
fact that we've not seen it in the buildfarm :-(.

			regards, tom lane