Horton

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

Robert Haas <robertmhaas@gmail.com>

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From: Robert Haas <robertmhaas@gmail.com>
To: Dave Cramer <davecramer@gmail.com>
Cc: Heikki Linnakangas <hlinnaka@iki.fi>, Jacob Champion <jacob.champion@enterprisedb.com>, Jelte Fennema-Nio <postgres@jeltef.nl>, Tom Lane <tgl@sss.pgh.pa.us>, Jacob Burroughs <jburroughs@instructure.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: 2024-08-16T20:34:52Z
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 →

  1. libpq: Add min/max_protocol_version connection options

  2. libpq: Handle NegotiateProtocolVersion message differently

  3. Add PQfullProtocolVersion() to surface the precise protocol version.

  4. Do not hardcode PG_PROTOCOL_LATEST in NegotiateProtocolVersion

  5. libpq: Handle NegotiateProtocolVersion message

  6. Provide for forward compatibility with future minor protocol versions.

On Fri, Aug 16, 2024 at 4:03 PM Dave Cramer <davecramer@gmail.com> wrote:
> Admittedly I'm a bit late into this discussion so I may be off base.
> Ultimately we need to negotiate the protocol. From what I can tell for libpq we are providing a function that returns a number, currently 3.
>
> The proposal is to change it to something like 30000.
>
> Ultimately this has to go over the wire so that clients that are implementing the protocol themselves can respond to the new behaviour.
>
> Wouldn't we have to send this number in the protocol negotiation ?

See the discussion of the NegotiateProtocolVersion message which has
been around for a long time but is still not supported by all clients.

https://www.postgresql.org/docs/current/protocol.html
https://www.postgresql.org/docs/current/protocol-message-formats.html

No changes to the format of that message are proposed. The startup
message also contains a version number, and changes the format of that
message are also not proposed.

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