From: Tom Lane <tgl@sss.pgh.pa.us>
To: Andres Freund <andres@anarazel.de>
cc: Simon Riggs <simon@2ndquadrant.com>, Robert Haas <robertmhaas@gmail.com>,
        Konstantin Knizhnik <k.knizhnik@postgrespro.ru>,
        Stephen Frost <sfrost@snowman.net>,
        Michael Paquier <michael.paquier@gmail.com>,
        Alvaro Herrera <alvherre@alvh.no-ip.org>,
        Christoph Berg <myon@debian.org>,
        Thomas Munro <thomas.munro@enterprisedb.com>,
        Peter Eisentraut <peter.eisentraut@2ndquadrant.com>,
        PostgreSQL Hackers <pgsql-hackers@postgresql.org>
Subject: Re: [HACKERS] Surjective functional indexes
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Comments: In-reply-to Andres Freund <andres@anarazel.de>
	message dated "Mon, 14 Jan 2019 15:09:18 -0800"
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Date: Mon, 14 Jan 2019 18:19:08 -0500
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Andres Freund <andres@anarazel.de> writes:
> On 2019-01-14 18:03:24 -0500, Tom Lane wrote:
>> Do we want to revert entirely, or leave the "recheck_on_update" option
>> present but nonfunctional?

> I think it depends a bit on whether we want to revert in master or
> master and 11. If only master, I don't see much point in leaving the
> option around. If both, I think we should (need to?) leave it around in
> 11 only.

After a few minutes' more thought, I think that the most attractive
option is to leave v11 alone and do a full revert in HEAD.  In this
way, if anyone's attached "recheck_on_update" options to their indexes,
it'll continue to work^H^H^H^Hdo nothing in v11, though they won't be
able to migrate to v12 till they remove the options.  That way we
aren't bound to the questionable design and naming of that storage
option if/when we try this again.

A revert in v11 would have ABI compatibility issues to think about,
and would also likely be a bunch more work on top of what we'll
have to do for HEAD, so leaving it as-is seems like a good idea.

			regards, tom lane