Group Aggregation
SELECT Permission
- 
                                                GRANT SELECT ON dba_roles TO ${UserName}; (By this command discovering schema is possible) 
- 
                                                GRANT SELECT ON dba_tab_privs TO ${UserName}; 
- 
                                                GRANT SELECT ON dba_col_privs TO ${UserName}; 
- 
                                                GRANT SELECT ON dba_sys_privs TO ${UserName}; 
- 
                                                GRANT SELECT ON system_privilege_map TO ${UserName}; 
- 
                                                GRANT SELECT ON V_$version TO ${UserName}; 
- 
                                                GRANT SELECT on V_$PWFILE_USERS to ${UserName}; 
- 
                                                GRANT SELECT ON dba_role_privs TO ${UserName}; 
Note
                                            
To view Sysdba privileges: SELECT * FROM V$PWFILE_USERS
For the CDB service account, the above permissions must be in the following format:
GRANT SELECT ON dba_roles TO <C##username> container=CURRENT;