Dominique Devienne <ddevienne(at)gmail(dot)com> writes:
> Final step is to DROP the "owner" ROLE itself, but before doing that,
> I run REVOKE ALL ON DATABASE "ddevienne" FROM "owner".
That will only revoke privileges that were granted by the role
doing the REVOKE, so I surmise that you did this as some other role.
But actually capturing the DB's privileges at the point where the
DROP ROLE is failing would help you debug.
regards, tom lane