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

Robert Haas <robertmhaas@gmail.com> writes:
> I think that we really need to think about allowing clients to tell
> the server which GUCs they'd like reported, instead of having a single
> list to which everyone is bound.

Interesting idea ...

> As a side benefit, then Craig and Tom can stop arguing about whether
> server_version_num should be GUC_REPORT.  Under this proposal, you can
> have it whichever way you like.

... but I don't think it fixes that, because you couldn't send this new
request without making an assumption about the server version being
new enough to support it.  My entire beef with making server_version_num
be GUC_REPORT is that it would encourage people to write client code that
fails outright against older servers.  I'm afraid what you are suggesting
will be an equally attractive nuisance.

            regards, tom lane