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

Jacob Champion <jacob.champion@enterprisedb.com>

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

To: Jelte Fennema-Nio <me@jeltef.nl>

Cc: Robert Haas <robertmhaas@gmail.com>, Dave Cramer <davecramer@gmail.com>, Peter Smith <smithpb2250@gmail.com>, Tom Lane <tgl@sss.pgh.pa.us>, Jacob Burroughs <jburroughs@instructure.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: 2024-04-23T17:39:15Z

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 Mon, Apr 22, 2024 at 2:20 PM Jelte Fennema-Nio <me@jeltef.nl> wrote:
> 1. I strongly believe minor protocol version bumps after the initial
> 3.1 one can be made painless for clients/poolers (so the ones to
> 3.2/3.3/etc). Similar to how TLS 1.3 can be safely introduced, and not
> having to worry about breaking TLS 1.2 communication.

Apologies for focusing on a single portion of your argument, but this
claim in particular stuck out to me. To my understanding, IETF worried
a _lot_ about breaking TLS 1.2 implementations with the TLS 1.3
change, to the point that TLS 1.3 clients and servers advertise
themselves as TLS 1.2 and sneak the actual version used into a TLS
extension (roughly analogous to the _pq_ stuff). I vaguely recall that
the engineering work done for that update was pretty far from
painless.

--Jacob