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From: Tom Lane <tgl@sss.pgh.pa.us>
To: Alvaro Herrera <alvherre@2ndquadrant.com>
cc: Robert Haas <robertmhaas@gmail.com>,
 Michael Paquier <michael@paquier.xyz>,
        Andres Freund <andres@anarazel.de>,
        PostgreSQL Hackers <pgsql-hackers@postgresql.org>
Subject: Re: TopoSort() fix
In-reply-to: <20190730032157.GA652@alvherre.pgsql>
References: <20190730032157.GA652@alvherre.pgsql>
Comments: In-reply-to Alvaro Herrera <alvherre@2ndquadrant.com>
	message dated "Mon, 29 Jul 2019 23:21:57 -0400"
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Alvaro Herrera <alvherre@2ndquadrant.com> writes:
> On 2019-Jul-29, Tom Lane wrote:
>> FYI, I just got done inventing a way to reach that code, and I have
>> to suspect that it's impossible to do so in production, because under
>> ordinary circumstances no parallel worker will take any exclusive lock
>> that isn't already held by its leader.

> Hmm, okay, so this wasn't a bug that would have bit anyone in practice,
> yeah?  That's reassuring.

At the least, you'd have to go well out of your way to make it happen.

			regards, tom lane