Re: PROXY protocol support

On Thu, Mar 4, 2021 at 10:01 PM Jan Wieck <jan(at)wi3ck(dot)info> wrote:
>
> On 3/4/21 3:40 PM, Magnus Hagander wrote:
> > On Thu, Mar 4, 2021 at 9:29 PM Jan Wieck <jan(at)wi3ck(dot)info> wrote:
> >> This looks like it would only need a few extra protocol messages to be
> >> understood by the backend. It might be possible to implement that with
> >> the loadable wire protocol extensions proposed here:
> >>
> >> https://commitfest.postgresql.org/32/3018/
> >
> > Actually the whole point of it is that it *doesn't* need any new
> > protocol messages. And that it *wraps* whatever is there, definitely
> > doesn't replace it. It should equally be wrapping whatever an
> > extension uses.
> >
> > So while the base topic is not unrelated, I don't think there is any
> > overlap between these.
>
> I might be missing something here, but isn't sending some extra,
> informational *header*, which is understood by the backend, in essence a
> protocol extension?

Bad choice of words, I guess.

The points being, there is a single packet sent ahead of the normal
stream. There are no new messages in "the postgresql protocol" or "the
febe protocol" or whatever we call it. And it doesn't change the
properties of any part of that protocol. And, importantly for the
simplicity, there is no negotiation and there are no packets going the
other way.

But sure, you can call it a protocol extension if you want. And yes,
it could probably be built on top of part of the ideas in that other
patch, but most of it would be useless (the abstraction of the listen
functionality into listen_have_free_slot/listen_add_socket would be
the big thing that could be used)

--
Magnus Hagander
Me: https://www.hagander.net/
Work: https://www.redpill-linpro.com/