The objects can't be owned by nothing, so you will need to reassign ownership: REASSIGN OWNED BY old_role TO new_role; e.g. REASSIGN OWNED BY vantaa TO postgres; Then you can drop the role.
User who deletes other users is not superuser. It is created using
CREATE ROLE admin LOGIN NOSUPERUSER INHERIT CREATEDB CREATEROLE NOREPLICATION CONNECTION LIMIT 100; GRANT idd_owner TO admin;
I tried
So to be clear admin is doing the below, correct?
REASSIGN OWNED BY vantaa TO postgres;
and
REASSIGN OWNED BY vantaa TO idd_owner;
but got error
permission denied to reassign objects .
Is the above a blanket error or does it mention specific objects?
How to fix ?
What you are trying to do is reverse what you did to get the present setup. Do you have a record/script that shows what you did to create the role and assign it to the objects?
I can add some rights to user who invokes this command if this helps.