Re: Extensions versus pg_upgrade

Robert Haas <robertmhaas(at)gmail(dot)com> writes:
> On Tue, Feb 8, 2011 at 9:48 PM, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
>> Like ALTER THING SET SCHEMA, ALTER THING SET EXTENSION is implicitly
>> assuming that there can be only one owning extension for an object.

> I would assume that we would enforce that constraint anyway. No?
> Otherwise when you drop one of the two extensions, what happens to the
> object? Seems necessary for sanity.

Not sure --- what about nested extensions, for instance? Or you could
think about objects that are shared between two extensions, and go away
only if all those extensions are dropped. (RPM has exactly that
behavior for files owned by multiple packages, to take a handy example.)

My point is that the current restriction to just one containing
extension seems to me to be an implementation restriction, rather than
something inherent in the concept of extensions. I have no intention of
trying to relax that restriction in the near future --- I'm just
pointing out that it could become an interesting thing to do.

regards, tom lane