"David G. Johnston" <david.g.johnston@gmail.com> writes:
> On Tuesday, May 31, 2022, PG Doc comments form <noreply@postgresql.org>
> wrote:
>> I'm trying to add an extension to two schemas that I have in my DB.
> It doesn’t work and isn’t documented as something that does work. I really
> don’t see a need to say you cannot install the same extension multiple
> times explicitly - the self-describing error seems sufficient.
The CREATE EXTENSION reference page says
"There must not be an extension of the same name already loaded."
and later
"Remember that the extension itself is not considered to be within any
schema: extensions have unqualified names that must be unique
database-wide. But objects belonging to the extension can be within
schemas."
I hardly see how we could make this any plainer.
regards, tom lane