Subject: Re: Time to drop RADIUS support?

From: Tom Lane <[email-masked]>
Date: Fri, 23 Jan 2026 11:30:07 -0500

=?utf-8?Q?=C3=81lvaro?= Herrera <[email-masked]> writes:
> Would it work to add a WARNING (or something) to all back branches to
> ask users to write here, so that we can confirm in the next few months
> whether the protocol is completely unused or not?  If we do find users,
> then we could try to think of workarounds[*], but otherwise we'd just
> remove it for pg19 (or pg20 at the latest) and not waste any more time
> on it.

I don't think that'd prove a lot.  Affected users (if any) wouldn't
necessarily be quick to adopt the latest minor releases.  They're
probably not even up-to-date on their RADIUS server, or they'd have
noticed it spewing complaints.

> I don't think removing it entirely from all back branches is a good
> idea, without first making sure that there are no users.

Agreed, we can't pull it from the back branches.  But I'm in favor of
pulling it from HEAD if we document how to use PAM-based RADIUS
instead.  I agree with Thomas' argument that the cost-benefit ratio
of fixing our implementation would be poor.

			regards, tom lane

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From: Jacob Champion <[email-masked]>
Date: Fri, 23 Jan 2026 09:50:40 -0800

> of fixing our implementation would be poor.

+1.

I still think a WARNING in the back branches would be a kindness, to
let people know that they need to move.

--Jacob

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From: Thomas Munro <[email-masked]>
Date: Sun, 25 Jan 2026 12:14:19 +1300

> > of fixing our implementation would be poor.

Great, it sounds like we have a plan.  I think the wiki might be a
good place for that documentation.  The details are likely to change,
and I wouldn't want to have to maintain that information in-tree, so I
created some PAM how-to documentation at
https://wiki.postgresql.org/wiki/RADIUS after testing on Debian and
FreeBSD.  We could point to that from the 19 release notes and in the
deprecation notice added to the documentation for 14-18, calling it
"community-maintained guidance on migration to supported
configurations".  Do we need to keep any trace of this in the 19 docs,
and if so, where?  A new tombstone section?