You have created a resource plan， DB_PLAN， using DBMS_RESOURCE_MANAGER.CREATE_SIMPLE_PLAN and you want to impose a restriction on utilization of resources by the database users.  
Which step must be performed before you can start using the resource plan？（）

多项选择题In your production database， you observe that users’ transactions are consuming a lot of resources and you plan to impose resource restrictions by using Resource Manager.  For which three resources can you enable usage restrictions by using Resource Manager？（）

A.CPU usage
B.degree of parallelism
C.number of open cursors
D.number of sorts performed
E.idle time for blocking sessions
F.number of disk I/O operations performed
G.number of memory I/O operations performed

单项选择题From the V$SESSION_LONGOPS view， you find that some of the database users have long-running queries that consume a lot of CPU time. This causes performance problems for other users in the database， who have much shorter queries.  You would like to make sure that the users with large queries do not use all the CPU time， but you still do not want to terminate them with an error message.  Which method would you follow to achieve this？（）

A.set the CPU time per call in the users profile
B.set the CPU time per session in the users profiles
C.set the CPU levels for the users’ group using Resource Manager
D.set the TIMED_STATISTICS parameter to TRUE in the parameter file