Date: Tue, 14 Sep 2021 14:55:53 -0300
From: Alvaro Herrera <alvherre@alvh.no-ip.org>
To: Kyotaro Horiguchi <horikyota.ntt@gmail.com>
Cc: bossartn@amazon.com, andres@anarazel.de, masao.fujii@oss.nttdata.com,
	pgsql-hackers@lists.postgresql.org, mengjuan.cmj@alibaba-inc.com,
	Jakub.Wartak@tomtom.com
Subject: Re: prevent immature WAL streaming
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On 2021-Sep-08, Kyotaro Horiguchi wrote:

> Thanks!  As my understanding the new record add the ability to
> cross-check between a teard-off contrecord and the new record inserted
> after the teard-off record.  I didn't test the version by myself but
> the previous version implemented the essential machinery and that
> won't change fundamentally by the new record.
> 
> So I think the current patch deserves to see the algorithm actually
> works against the problem.

Here's a version with the new record type.  It passes check-world, and
it seems to work correctly to prevent overwrite of the tail end of a
segment containing a broken record.  This is very much WIP still;
comments are missing and I haven't tried to implement any sort of
verification that the record being aborted is the right one.

-- 
Álvaro Herrera         PostgreSQL Developer  —  https://www.EnterpriseDB.com/
"XML!" Exclaimed C++.  "What are you doing here? You're not a programming
language."
"Tell that to the people who use me," said XML.
https://burningbird.net/the-parable-of-the-languages/