From: Tom Lane <tgl@sss.pgh.pa.us>
To: Andres Freund <andres@anarazel.de>
cc: Peter Eisentraut <peter.eisentraut@enterprisedb.com>,
        pgsql-hackers@postgresql.org
Subject: Re: Time to drop plpython2?
In-reply-to: <20211115200019.fo7pnwndavbhr5oo@alap3.anarazel.de>
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Comments: In-reply-to Andres Freund <andres@anarazel.de>
	message dated "Mon, 15 Nov 2021 12:00:19 -0800"
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Date: Mon, 15 Nov 2021 15:30:02 -0500
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Andres Freund <andres@anarazel.de> writes:
> On 2021-11-15 14:26:55 -0500, Tom Lane wrote:
>> * Meson only promises support back to python 3.6, but if that's
>> accurate it's going to be a problem for us, because there are lots
>> of live LTS distributions with older python3 (RHEL7, Solaris 11.3,
>> AIX 7.2 for starters).  I've been planning to do some testing and
>> see if meson will run under python 3.4 or 3.5.

> Slightly older versions, which do work to build postgres with the propos=
ed
> patchset, run on python3 3.5. I don't think it's likely we could make th=
e
> versions that only required 3.4 work reasonably.

OK, thanks for the datapoint.

> Is RHEL7 really an issue? I only have Centos 7 around, but that has pyth=
on
> 3.6.

The info I checked said that RHEL7 originally shipped with 3.3.
I'm not sure that Red Hat would've outright replaced that, but they
do have a notion of add-on "software collections", and I'm certain
that they would have provided newer pythons via that mechanism.
So it should only be a big issue for someone who didn't want to install
an add-on collection.  I suppose the overlap of that group with the
people who will want to put PG 15+ on that platform is probably nil.

> I don't know much about AIX, but according to https://repology.org/proje=
ct/python/versions
> the AIX toolbox has 3.7.11. I don't know enough about AIX to know whethe=
r
> there's other sources of python3, bison, etc that are common. On the AIX
> system I have access to they all seem to be symlinked to /opt/freeware, =
which
> I understand is that toolbox stuff?

Hmm, I was basing that on (a) what I can see installed on gcc119,
which is 3.5.1, and (b) AIX 7.2's 2015 release date, which matches up
pretty well with python 3.5.  As with RHEL, it's entirely likely that
IBM has made newer releases available as add-ons, but there's no
guarantee that any given installation would have that.

Solaris is a bit worse, since they shipped 11.3 a shade earlier,
with python 3.4.3.  No idea about add-on conventions on that
platform.

There's room to argue that all three of these will be out of
primary support before PG15 ships, so maybe we don't need to
worry about whether we can build with their default toolsets.
Still, it's a tradeoff I'd rather not make.

			regards, tom lane