Alvaro Herrera <alvherre@alvh.no-ip.org> writes:
> Well, this does sound unsatisfactory. I suppose one answer would be to
> load the module in all backends, in case the user wants to look at the
> value. But that would be wasteful. Maybe we should have a warning
> about it in the docs -- tell people to LOAD the library if they want to
> examine the configuration?
The underlying issue here is that the pg_settings view doesn't show
placeholder GUCs because we lack satisfactory values to put in
most of the columns. I don't know if revisiting that conclusion
would be appropriate or not. The purist approach would be to show
NULL for any unknown column, but how many applications would that
break? And even the "known" values could change unexpectedly when
the module does get loaded, for example if the GUC has units and
the value in the config file is expressed in a non-canonical way.
(To say nothing of what a show hook might do...)
regards, tom lane