Re: PG18 protocol version

On Thu, 26 Jun 2025 at 13:34, Tatsuo Ishii <ishii(at)postgresql(dot)org> wrote:
>
> > I didn't? I replaced it with a more generic version of the same
> > information, that covers both protocol version 3.0 and 3.2 (and any
> > future 3.x)
>
> I meant this.
> >> - (0 for the protocol described here).
>
> With your patch the explanation that this document (Message Formats)
> is for 3.2, is gone. But maybe it's okay since "54.1.4. Protocol
> versions" already stats that the whole F/B protocol docs is for 3.2.
>
> What do you think?

Let me rephrase what you are saying to be sure I understand it
correctly: Since it's stated in the page that the page describes the
3.2 protocol specifically, arguably there's only one valid
StartupMessage within that context, i.e. the one with 196610.

I agree that that's strictly true, but I think I still prefer my newly
proposed wording for a few reasons:
1. My new wording is generic enough that we don't need to update it in
the future.
2. A 3.2 server will currently still receive a 3.0 message, and might
want to support downgrading. Or maybe it will get a 3.3
StartupMessage, to which it should respond with a
NegotiateProtocolVersion message. The new wording makes it clear that
the version in the StartupMessage isn't necessarily a fixed number.
3. As a user of the docs I think the 196608/196610 decimal is more
confusing than helpful. Anything that implements the protocol would
benefit from using the hexadecimal representation instead in its code
(at least until we reach protocol version 3.10).