Re: custom parameters cannot be removed once set

Joe Conway <mail@joeconway.com> writes:
> Today I was reminded of an issue I have run across before, namely that
> in a given postgres session, once a custom parameter has been set, there
> is no way to remove it entirely.

True.

> This strikes me as, at least, surprising, and possibly should be
> considered a bug. Thoughts?

Meh.  The real problem here is that people are abusing the custom-GUC
mechanism to implement session-lifespan variables.  I do not think we
should encourage that; GUC offers neither adequate features for that
(eg, no way to declare a variable's type) nor adequate performance
(it's not going to scale to very many variables).

I'd rather see us invent a real session-variable mechanism instead
of putting yet more demands on GUC that have nothing to do with its
primary mission, and indeed are antithetical to it.
        regards, tom lane