From: Tom Lane <tgl@sss.pgh.pa.us>
To: Noah Misch <noah@leadboat.com>
cc: pgsql-committers@lists.postgresql.org
Subject: Re: pgsql: Consistently test for in-use shared memory.
In-reply-to: <20190416005019.GA3296237@rfd.leadboat.com>
References: <E1hFBbx-0002OI-Pb@gemulon.postgresql.org>
 <26478.1555373328@sss.pgh.pa.us> <20190416005019.GA3296237@rfd.leadboat.com>
Comments: In-reply-to Noah Misch <noah@leadboat.com>
	message dated "Mon, 15 Apr 2019 17:50:19 -0700"
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Date: Mon, 15 Apr 2019 20:52:36 -0400
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Noah Misch <noah@leadboat.com> writes:
> On Mon, Apr 15, 2019 at 08:08:48PM -0400, Tom Lane wrote:
>> I interpret this as "the single-user backend exited before we could stu=
ff
>> 'SELECT 1 + 1' down the pipe to it, and the Perl script is not expectin=
g
>> to get a write failure there".

> Perhaps I should write the 'SELECT 1 + 1' to a regular file and redirect=
 input
> from that file.

Yeah, that was the first idea that occurred to me as well.
Kinda grotty, but ...

Another idea is to shove the problem off on a sub-shell, that is run

	echo SELECT 1 + 1 | postgres --single ...

			regards, tom lane