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

On Tue, Aug 20, 2024 at 12:55 PM Jelte Fennema-Nio <postgres@jeltef.nl> wrote:
> Another way of describing this guarantee: If a client connects using
> 3.8 and configures no protocol parameters, the client needs to handle
> anything 3.8 specific that the handshake requires (such as longer
> cancel token). But then after that handshake it can choose to send
> only 3.0 packets and expect to receive only 3.0 packets back.

That guarantee (if adopted) would also make it possible for my use
case to proceed correctly, since a libpq client can still speak 3.0
packets on the socket safely. But in that case, PQprotocolVersion
should keep returning 3, because there's an explicit reason to care
about the major version by itself.

--Jacob