From: Tom Lane <tgl@sss.pgh.pa.us>
To: vignesh C <vignesh21@gmail.com>
cc: Greg Nancarrow <gregn4422@gmail.com>,
        Alvaro Herrera <alvherre@alvh.no-ip.org>,
        Anastasia Lubennikova <a.lubennikova@postgrespro.ru>,
        Peter Smith <smithpb2250@gmail.com>,
        "Smith,
    Peter" <peters@fast.au.fujitsu.com>,
        David Steele <david@pgmasters.net>,
        "Tsunakawa,
    Takayuki" <tsunakawa.takay@fujitsu.com>,
        Haribabu Kommi <kommi.haribabu@gmail.com>,
        Robert Haas <robertmhaas@gmail.com>,
        Laurenz Albe <laurenz.albe@cybertec.at>,
        Dave Cramer <pg@fastcrypt.com>, Jing Wang <jingwangian@gmail.com>,
        PostgreSQL-development <pgsql-hackers@postgresql.org>,
        Elvis Pranskevichus <elprans@gmail.com>
Subject: Re: Libpq support to connect to standby server as priority
In-reply-to: <1149041.1614746350@sss.pgh.pa.us>
References: <20201124225917.GA21884@alvherre.pgsql>
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 <1149041.1614746350@sss.pgh.pa.us>
Comments: In-reply-to Tom Lane <tgl@sss.pgh.pa.us>
	message dated "Tue, 02 Mar 2021 23:39:10 -0500"
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Date: Wed, 03 Mar 2021 13:54:18 -0500
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I wrote:
> vignesh C <vignesh21@gmail.com> writes:
>> Conchuela is failing because of:
>> ok 17 - connect to node standby_1 if mode "standby" and standby_1,primary
>> listed
>> ack Broken pipe: write( 13, 'SHOW port;' ) at
>> /usr/local/lib/perl5/site_perl/IPC/Run/IO.pm line 549.

> It didn't fail on the next run, so this might just be a phase-of-the-moon
> glitch.  Conchuela is a bit prone to that sort of thing, in my experience.
> We'll have to wait and see if it's at all repeatable.

Conchuela hasn't shown it again, but it turns out to be repeatable
on my old warhorse gaur.  After a bit of study I see the problem:
we're asking Perl to write to the stdin of a psql process that
may not be there to receive the data.  We've dodged that issue
in other tests by passing "undef" as the stdin to sub psql, so
that's what I did here.

			regards, tom lane