Horton

Re: pgsql: libpq: Grease the protocol by default

Tom Lane <tgl@sss.pgh.pa.us>

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From: Tom Lane <tgl@sss.pgh.pa.us>
To: Jacob Champion <jacob.champion@enterprisedb.com>
Cc: Jelte Fennema-Nio <postgres@jeltef.nl>, pgsql-hackers@lists.postgresql.org, Andrew Dunstan <andrew@dunslane.net>
Date: 2026-02-23T23:34:42Z
Lists: pgsql-hackers 
Jacob Champion <jacob.champion@enterprisedb.com> writes:
> On Mon, Feb 23, 2026 at 2:18 PM Tom Lane <tgl@sss.pgh.pa.us> wrote:
>> Either that or we decide that it's time to throw 9.2 support
>> overboard (looks like 9.3 and up are fine).

> Well, while I was hacking on a patch I realized that 9.3 (all the way
> up to 10) is only okay if you're running a sufficiently patched
> version. PG11 is the first to support negotiation for the whole
> release line.

Hmm ... and of course the whole point of this exercise is to be sure
we can pg_upgrade from those out-of-support versions.

> I think Jelte said it well back on the -committers thread:
>> Why only force max_protocol_version=3.0 for beta? It sounds like
>> this would also be an issue once we eventually bump the default
>> version.

> So a fix belongs in pg_upgrade, IMO, instead of the test. I have a
> draft passing locally that I should be able to share soon.

Fair enough.

			regards, tom lane

Commits

  1. pg_upgrade: Use max_protocol_version=3.0 for older servers

  2. libpq: Grease the protocol by default

  3. libpq: Prepare for protocol grease during 19beta