Re: Add new protocol message to change GUCs for usage with future protocol-only GUCs

Robert Haas <robertmhaas@gmail.com>

From: Robert Haas <robertmhaas@gmail.com>

To: Jacob Champion <jacob.champion@enterprisedb.com>

Cc: Jelte Fennema-Nio <postgres@jeltef.nl>, Heikki Linnakangas <hlinnaka@iki.fi>, Tom Lane <tgl@sss.pgh.pa.us>, Jacob Burroughs <jburroughs@instructure.com>, Dave Cramer <davecramer@gmail.com>, Peter Smith <smithpb2250@gmail.com>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>, "Andrey M. Borodin" <x4mmm@yandex-team.ru>, Pavel Stehule <pavel.stehule@gmail.com>, Jeff Davis <pgsql@j-davis.com>, Peter Eisentraut <peter@eisentraut.org>

Date: 2024-08-16T18:01:15Z

Lists: pgsql-hackers

Commits

Same data as JSON: GET /api/v1/messages/:b64id/commits the thread's linked commits as JSON, with link sources. API reference →

libpq: Add min/max_protocol_version connection options
- 285613c60a7a 18.0 landed
libpq: Handle NegotiateProtocolVersion message differently
- 5070349102af 18.0 landed
Add PQfullProtocolVersion() to surface the precise protocol version.
- cdb6b0fdb0b2 18.0 landed
Do not hardcode PG_PROTOCOL_LATEST in NegotiateProtocolVersion
- 516b87502dc1 18.0 landed
libpq: Handle NegotiateProtocolVersion message
- bbf9c282ce92 16.0 cited
Provide for forward compatibility with future minor protocol versions.
- ae65f6066dc3 11.0 cited

On Fri, Aug 16, 2024 at 1:44 PM Jacob Champion
<jacob.champion@enterprisedb.com> wrote:
>     https://github.com/psycopg/psycopg2/blob/658afe4cd90d3e167d7c98d22824a8d6ec895b1c/tests/test_async.py#L89
>     https://github.com/infusion/PHP/blob/7ebefb6426bb4b4820a30cca5c3a10bfd757b6ea/ext/pgsql/pgsql.c#L864

IMHO these examples establish beyond doubt that the existing function
really is being used in ways that would break if we committed the
proposed patch. To be honest, I'm slightly surprised, because protocol
version 2 has been so dead for so long that I would not have
anticipated people would even bother checking for it. But these
examples show that some people do. If Jacob found these examples this
easily, there are probably a bunch of others.

It's not worth breaking existing code to avoid adding one new libpq
entrypoint. Let's just add the new function and move on.

-- 
Robert Haas
EDB: http://www.enterprisedb.com