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From: Peter Geoghegan <pg@bowt.ie>
Date: Wed, 16 Feb 2022 10:14:19 -0800
Message-ID: <CAH2-Wz=5RuakSPA9euKmUCa3WX5HB2GFeLd7xKXyH5AwbpCGtg@mail.gmail.com>
Subject: Re: do only critical work during single-user vacuum?
To: Robert Haas <robertmhaas@gmail.com>
Cc: Masahiko Sawada <sawada.mshk@gmail.com>, John Naylor <john.naylor@enterprisedb.com>, 
	Andres Freund <andres@anarazel.de>, 
	PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
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On Wed, Feb 16, 2022 at 9:56 AM Robert Haas <robertmhaas@gmail.com> wrote:
> +1. But I think we might want to try to write documentation around
> this. We should explicitly tell people NOT to use single-user mode,
> because that stupid message has been there for a long time and a lot
> of people have probably internalized it by now. And we should also
> tell them that they SHOULD check for prepared transactions, old
> replication slots, etc.

Absolutely -- couldn't agree more. Do you think it's worth targeting
14 here, or just HEAD?

I'm pretty sure that some people believe that wraparound can cause
actual data corruption, in part because of the way the docs present
the information. The system won't do that, of course (precisely
because of this xidStopLimit behavior). The docs make it all sound
absolutely terrifying, which doesn't seem proportionate to me (at
least not with this stuff in place, maybe not ever).

-- 
Peter Geoghegan