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

On Fri, 5 Apr 2024 at 18:30, Dave Cramer <davecramer@gmail.com> wrote:
>> > I really intended the _pq_ prefix as a way of taking something out of
>> > the GUC namespace, not as a part of the GUC namespace that users would
>> > see. And I'm reluctant to go back on that. If we want to make
>> > pg_protocol.${NAME} mean a wire protocol parameter, well maybe there's
>> > something to that idea [insert caveats here]. But doesn't _pq_ look
>> > like something that was intended to be internal? That's certainly how
>> > I intended it.
>
>
> Is this actually used in practice? If so, how ?

No, it's not used for anything at the moment. This whole thread is
basically about trying to agree on how we want to make protocol
changes in the future in a somewhat standardized way. But using the
tools available that we have to not break connecting to old postgres
servers: ProtocolVersionNegotation messages, minor version numbers,
and _pq_ parameters in the startup message. All of those have so far
been completely theoretical and have not appeared in any client-server
communication.