tpch1s=# \du
                                       List of roles
 Role name |                              Attributes                        | Member of 
-----------+----------------------------------------------------------------+-----------
 gpadmin   | Superuser, Create role, Create DB, Ext http Table, Replication | {}
 yz        | Superuser, Create role, Create DB, Replication                 | {gpadmin}
 
tpch1s=# ALTER ROLE yz with NOSUPERUSER;
tpch1s=# \du
                                       List of roles
 Role name |                              Attributes                        | Member of 
-----------+----------------------------------------------------------------+-----------
 gpadmin   | Superuser, Create role, Create DB, Ext http Table, Replication | {}
 yz        | Create role, Create DB, Replication                            | {gpadmin}