Re: Enhancement Idea - Expose the active value of a parameter in pg_settings

Robert Haas <robertmhaas(at)gmail(dot)com> writes:
> On Fri, May 25, 2018 at 10:11 AM, Andrew Dunstan
> <andrew(dot)dunstan(at)2ndquadrant(dot)com> wrote:
>> He's proposing an extra column to show the actual value used, so
>> distinguishing them should be a problem.

> For most settings, that column would just be a duplicate. For a
> handful, it would pull in the value of some other GUC. If somebody
> finds that useful, cool, they can write a view that does it and
> install it on their own cluster. I don't think that it makes a lot of
> sense to put it in core, though. My guess would be that more people
> would be annoyed or confused by the extra column than would be pleased
> or enlightened by it. I could of course be wrong.

Yeah, that's pretty much my evaluation --- given the tiny number of
GUCs that have behaviors like this, an extra column seems like it
would mostly be confusing. Plus, pg_settings is too darn wide already.

Personally, what I'd rather do is try to get rid of GUC behaviors like
"the effective value depends on something else". But convenience and
backwards compatibility may be arguments against that.

regards, tom lane