Andreas Joseph Krogh <andreas@visena.com> writes: > Hi, is there a way to prevent a user/role from SELECT-ing from certain > system-tables? > I'd like the contents of pg_{user,roles,database} to not be visible to all > users.
As noted, you can in principle revoke the public SELECT grant from those views/catalogs. However, the system is not designed to hide such information, which means you'll have (at least) two kinds of issues to worry about:
1. Queries or tools breaking that you didn't expect to break. It's hardly uncommon for instance for queries on pg_class to join to pg_roles to get the owner names for tables.
2. Information leaks. For example, mapping role OID to role name is trivial with either regrole or pg_get_userbyid(), so it wouldn't take long to scan the plausible range of role OIDs and get all their names, even without SQL access to the underlying catalog.