Subject: Re: [PATCH] remove deprecated v8.2 containment operators
To: Justin Pryzby <pryzby@telsasoft.com>, Stephen Frost <sfrost@snowman.net>
Cc: Magnus Hagander <magnus@hagander.net>, Tom Lane <tgl@sss.pgh.pa.us>,
 Peter Eisentraut <peter.eisentraut@enterprisedb.com>,
 Heikki Linnakangas <hlinnaka@iki.fi>,
 Ian Lawrence Barwick <barwick@gmail.com>,
 PostgreSQL-development <pgsql-hackers@postgresql.org>
References: <20201027032511.GF9241@telsasoft.com>
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 <235561.1605220100@sss.pgh.pa.us>
 <CABUevEyLtOAPtY3MYap0b6H23WmsrGHmFN6On6v7CDi14FORDw@mail.gmail.com>
 <20201113150343.GT16415@tamriel.snowman.net>
 <20201116205516.GM14024@telsasoft.com>
From: Anastasia Lubennikova <a.lubennikova@postgrespro.ru>
Message-ID: <ce7bcfe6-6505-3b36-49be-9e340053371f@postgrespro.ru>
Date: Mon, 30 Nov 2020 21:51:12 +0300
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On 16.11.2020 23:55, Justin Pryzby wrote:
> On Fri, Nov 13, 2020 at 10:03:43AM -0500, Stephen Frost wrote:
>> * Magnus Hagander (magnus@hagander.net) wrote:
>>> On Thu, Nov 12, 2020 at 11:28 PM Tom Lane <tgl@sss.pgh.pa.us> wrote:
>>>>> The changes to the contrib modules appear to be incomplete in some ways.
>>>>>    In cube, hstore, and seg, there are no changes to the extension
>>>>> scripts to remove the operators.  All you're doing is changing the C
>>>>> code to no longer recognize the strategy, but that doesn't explain what
>>>>> will happen if the operator is still used.  In intarray, by contrast,
>>>>> you're editing an existing extension script, but that should be done by
>>>>> an upgrade script instead.
>>>> In the contrib modules, I'm afraid what you gotta do is remove the
>>>> SQL operator definitions but leave the opclass code support in place.
>>>> That's because there's no guarantee that users will update the extension's
>>>> SQL version immediately, so a v14 build of the .so might still be used
>>>> with the old SQL definitions.  It's not clear how much window we need
>>>> give for people to do that update, but I don't think "zero" is an
>>>> acceptable answer.
>>> Based on my experience from the field, the answer is "never".
>>>
>>> As in, most people have no idea they are even *supposed* to do such an
>>> upgrade, so they don't do it. Until we solve that problem, I think
>>> we're basically stuck with keeping them "forever". (and even if/when
>>> we do, "zero" is probably not going to cut it, no)
>> Yeah, this is a serious problem and one that we should figure out a way
>> to fix or at least improve on- maybe by having pg_upgrade say something
>> about extensions that could/should be upgraded..?
> I think what's needed are:
>
> 1) a way to *warn* users about deprecation.  CREATE EXTENSION might give an
> elog(WARNING), but it's probably not enough.  It only happens once, and if it's
> in pg_restore/pg_upgrade, it be wrapped by vendor upgrade scripts.  It needs to
> be more like first function call in every session.  Or more likely, put it in
> documentation for 10 years.
>
> 2) a way to *enforce* it, like making CREATE EXTENSION fail when run against an
> excessively old server, including by pg_restore/pg_upgrade (which ought to also
> handle it in --check).
>
> Are there any contrib for which (1) is done and we're anywhere near doing (2) ?
>

Status update for a commitfest entry.

The commitfest is nearing the end and this thread is "Waiting on 
Author". As far as I see we don't have a patch here and discussion is a 
bit stuck.
So, I am planning to return it with feedback. Any objections?

-- 
Anastasia Lubennikova
Postgres Professional: http://www.postgrespro.com
The Russian Postgres Company