The view applicable_roles identifies all roles
   whose privileges the current user can use.  This means there is
   some chain of role grants from the current user to the role in
   question.  The current user itself is also an applicable role.  The
   set of applicable roles is generally used for permission checking.
   
   
  
Table 32-3. applicable_roles Columns
| Name | Data Type | Description | 
|---|
| grantee | sql_identifier | Name of the role to which this role membership was granted (may
       be the current user, or a different role in case of nested role
       memberships) | 
| role_name | sql_identifier | Name of a role | 
| is_grantable | character_data | YES if the grantee has the admin option on
       the role, NO if not |