Date: Fri, 6 May 2022 08:52:45 -0700
From: Nathan Bossart <nathandbossart@gmail.com>
To: Michael Paquier <michael@paquier.xyz>
Cc: Kyotaro Horiguchi <horikyota.ntt@gmail.com>,
	pgsql-hackers@lists.postgresql.org, masao.fujii@oss.nttdata.com
Subject: Re: Possible corruption by CreateRestartPoint at promotion
Message-ID: <20220506155245.GA3447568@nathanxps13>
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On Fri, May 06, 2022 at 07:58:43PM +0900, Michael Paquier wrote:
> And I have spent a bit of this stuff to finish with the attached.  It
> will be a plus to get that done on HEAD for beta1, so I'll try to deal
> with it on Monday.  I am still a bit stressed about the back branches
> as concurrent checkpoints are possible via CreateCheckPoint() from the
> startup process (not the case of HEAD), but the stable branches will
> have a new point release very soon so let's revisit this choice there
> later.  v6 attached includes a TAP test, but I don't intend to include
> it as it is expensive.

I was looking at other changes in this area (e.g., 3c64dcb), and now I'm
wondering if we actually should invalidate the minRecoveryPoint when the
control file no longer indicates archive recovery.  Specifically, what
happens if a base backup of a newly promoted standby is used for a
point-in-time restore?  If the checkpoint location is updated and all
previous segments have been recycled/removed, it seems like the
minRecoveryPoint might point to a missing segment.

-- 
Nathan Bossart
Amazon Web Services: https://aws.amazon.com