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

On Tue, Aug 20, 2024 at 7:26 AM Jelte Fennema-Nio <postgres@jeltef.nl> wrote:
> In practical terms I think that means for a minor version bump the
> format of the StartupMessage cannot be changed. Changing anything else
> is fair game for a minor protocol version bump.

I may be in a tiny minority here, but when I combine that statement
with your opinion from way upthread that

> IMHO, we
> should get to a state where protocol minor version bumps are so
> low-risk that we can do them whenever we add message types

then I don't see this effort ending up in a healthy place or with a
happy ecosystem. Pick any IETF-managed protocol, add on the statement
"we get to change anything we want in a minor version, and we reserve
the right to do it every single year", and imagine the chaos for
anyone who doesn't have power over both servers and clients.

To me it seems that what you're proposing is indistinguishable from
what most other protocols would consider a major version bump; it's
just that you (reasonably) want existing clients to be able to
negotiate multiple major versions in one round trip.

--Jacob