On Sun, 2024-06-16 at 11:27 +0200, Karsten Hilbert wrote: > > the collations themselves > > are defined by an external library, so the implementation is shared. > > Which in turn means I cannot at all truly _remove_ collations > from a cluster at the SQL level, only make them invisible > (and thereby not-to-be-used) inside a particular database by > removing them from pg_collations via DROP COLLATION, right ? As far as PostgreSQL is concerned, you can remove them. You cannot remove the C library, but a PostgreSQL user can only use the collation if there is a collation defined in PostgreSQL. (Actually, that's not quite true: in CREATE DATABASE, you can use ICU collations. That does not depend on the collations defined in pg_collation.) Also, there is nothing that keeps a user from running CREATE COLLATION to create a collation in a schema where the user can CREATE objects. I wouldn't try too hard to make it impossible for users to use a collation you don't want. Dropping the collations is good enough to keep a user from using the wrong collation by mistake. Yours, Laurenz Albe
