Re: let's make the list of reportable GUCs configurable (was Re: Add %r substitution for psql prompts to show recovery status)

On 01/10/2018 03:11 PM, Robert Haas wrote:

> it will only work on versions that support that option, but that is
> true of any new feature. Furthermore, they will easily be able to
> tell based on the reported server version whether or not their request
> for different behavior was accepted by the server. Therefore, if they
> write their code well, there should be no danger of a client thinking
> that they are getting behavior A while actually getting behavior B.

SSL certificates support a notion of 'extension' where a certificate
can include beyond-the-standard doodads that the party on the other
end might or might not understand, and they can be marked either
'critical' ("please refuse my connection if you don't understand
this one") or not ("we'll muddle along if you don't understand
that one").

Is there a notion like that in the pq protocol now? If not, and
a protocol bump becomes necessary to meet some need, would it be
worth adding such a notion at the same time, to simplify future
evolution?

-Chap