Date: Sat, 28 Aug 2021 10:40:42 +0900
From: Michael Paquier <michael@paquier.xyz>
To: Andres Freund <andres@anarazel.de>
Cc: Julien Rouhaud <rjuju123@gmail.com>, Bruce Momjian <bruce@momjian.us>,
	Daniel Gustafsson <daniel@yesql.se>,
	Denis Laxalde <denis.laxalde@dalibo.com>,
	Jehan-Guillaume de Rorthais <jgdr@dalibo.com>,
	PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Subject: Re: [PATCH] Disable bgworkers during servers start in pg_upgrade
Message-ID: <YSmUGhShJBBIcyZb@paquier.xyz>
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On Fri, Aug 27, 2021 at 12:28:42PM -0700, Andres Freund wrote:
> Isn't that just going to end up with extension code erroring out and/or
> blocking waiting for a bgworker to start?

Well, that's the point to block things during an upgrade.  Do you have
a list of requirements you'd like to see satisfied here?  POWA would
be fine with blocking the execution of bgworkers AFAIK (Julien feel
free to correct me here if necessary).  It could be possible that
preventing extension code to execute this way could prevent hazards as
well.  The idea from upthread to prevent any writes and/or WAL
activity is not really different as extensions may still generate an
error because of pg_upgrade's safety measures we'd put in, no?
--
Michael

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