Message-ID: <3404870c1a921bafbcd168c098088981fe082ab1.camel@cybertec.at>
Subject: Re: Postgres restart in the middle of exclusive backup and the
 presence of backup_label file
From: Laurenz Albe <laurenz.albe@cybertec.at>
To: Stephen Frost <sfrost@snowman.net>, Tom Lane <tgl@sss.pgh.pa.us>
Cc: Michael Paquier <michael@paquier.xyz>, SATYANARAYANA NARLAPURAM
	 <satyanarlapuram@gmail.com>, Pg Hackers <pgsql-hackers@postgresql.org>
Date: Tue, 30 Nov 2021 17:47:18 +0100
In-Reply-To: <20211130142042.GR26257@tamriel.snowman.net>
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	 <YZ7Amotspa4ve+91@paquier.xyz>
	 <CAHg+QDekOasWArvmPeOqhyTUHR40DsDOWyt7OaKxpQ7eFYqysw@mail.gmail.com>
	 <YaB3Oj4GfPOZ/3LC@paquier.xyz> <417711.1637940660@sss.pgh.pa.us>
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On Tue, 2021-11-30 at 09:20 -0500, Stephen Frost wrote:
> Greetings,
> 
> * Tom Lane (tgl@sss.pgh.pa.us) wrote:
> > Michael Paquier <michael@paquier.xyz> writes:
> > > On Thu, Nov 25, 2021 at 06:19:03PM -0800, SATYANARAYANA NARLAPURAM wrote:
> > > > If we are keeping it then why not make it better?
> > 
> > > Well, non-exclusive backups are better by design in many aspects, so I
> > > don't quite see the point in spending time on something that has more
> > > limitations than what's already in place.
> > 
> > IMO the main reason for keeping it is backwards compatibility for users
> > who have a satisfactory backup arrangement using it.  That same argument
> > implies that we shouldn't change how it works (at least, not very much).
> 
> There isn't a satisfactory backup approach using it specifically because
> of this issue, hence why we should remove it to make it so users don't
> run into this.

There is a satisfactory approach, as long as you are satisfied with
manually restarting the server if it crashed during a backup.

> I don't find the reasons brought up to continue to support exclusive
> backup to be at all compelling and the lack of huge issues with the new
> way restore works to make it abundently clear that we can, in fact,
> remove exclusive backup in a major version change without the world
> coming down.

I guess the lack of hue and cry was at least to a certain extent because
the exclusive backup API was deprecated, but not removed.

Yours,
Laurenz Albe