Subject: Re: Roadmap for FE/BE protocol redesign
From: Rod Taylor <rbt@rbt.ca>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: PostgreSQL Development <pgsql-hackers@postgresql.org>,
	pgsql-interfaces@postgresql.org
In-Reply-To: <19294.1047324622@sss.pgh.pa.us>
References: <19041.1047322279@sss.pgh.pa.us>
	<1047324016.99075.31.camel@jester>  <19294.1047324622@sss.pgh.pa.us>
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Date: 10 Mar 2003 14:41:36 -0500

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On Mon, 2003-03-10 at 14:30, Tom Lane wrote:
> Rod Taylor <rbt@rbt.ca> writes:
> > I'd be tempted to make a startup packet that will allow libpq to revert
> > back to old protocols easily enough for the future so that we can do=3D=
20
> > incremental changes to the protocol.
>=20
> We already have that: you send a startup packet with a version less than
> the latest, and the backend speaks that version to you.

Yes, but that requires you know the backend is less than the latest.

If you send version A, and the backend responds don't know A, but I know
A - 2, then libpq may want to try speaking A - 2.

> types without calling it a protocol revision.  The protocol need only
> specify "ignore any fields whose label you do not recognize".

This is probably just as good, if it's done for both sides.

--=20
Rod Taylor <rbt@rbt.ca>

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