Date: Fri, 14 Feb 2020 13:18:20 +0100
From: Dmitry Dolgov <9erthalion6@gmail.com>
To: Kyotaro Horiguchi <horikyota.ntt@gmail.com>
Cc: tomas.vondra@2ndquadrant.com, florisvannee@optiver.com, pg@bowt.ie,
	jesper.pedersen@redhat.com, david.rowley@2ndquadrant.com,
	alvherre@2ndquadrant.com, thomas.munro@gmail.com, jtc331@gmail.com,
	rafia.pghackers@gmail.com, jeff.janes@gmail.com,
	bhushan.uparkar@gmail.com, pgsql-hackers@postgresql.org,
	a.korotkov@postgrespro.ru
Subject: Re: Index Skip Scan
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> On Fri, Feb 14, 2020 at 05:23:13PM +0900, Kyotaro Horiguchi wrote:
> The first attached (renamed to .txt not to confuse the cfbots) is a
> small patch that makes sure if _bt_readpage is called with the proper
> condition as written in its comment, that is, caller must have pinned
> and read-locked so->currPos.buf. This patch reveals many instances of
> breakage of the contract.

Thanks! On top of which patch version one can apply it? I'm asking
because I believe I've addressed similar issues in the last version, and
the last proposed diff (after resolving some conflicts) breaks tests for
me, so not sure if I miss something.

At the same time if you and Tomas strongly agree that it actually makes
sense to make moving forward/reading backward case work with dead tuples
correctly, I'll take a shot and try to teach the code around _bt_skip to
do what is required for that. I can merge your changes there and we can
see what would be the result.