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

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
anumber, 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
thenew 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