I wrote:
> In short, maybe we ought to invent a new category PGC_SU_BACKEND (not
> wedded to this spelling), which is to PGC_BACKEND as PGC_SUSET is to
> PGC_USERSET, ie same when-it-can-be-changed behavior but only superusers
> are allowed to change it. I don't have any objection to making these two
> settings only adjustable by superusers --- I just don't want to give up
> the existing timing restrictions for them.
Another idea would be to get rid of PGC_SUSET as a separate category, and
instead have a superuser-only bit in the GUC flags, which would apply to
all categories. This would be a bit more orthogonal, though likely a
much more invasive change.
regards, tom lane