多项选择题
A. It does not allow you to change the moving window size.
B. Adaptive threshold functionalities use it by default to compute statistics.
C. It is created by default with the window size being equal to the AWR retention time.
D. It is created when the first snapshot is collected by the Automatic Workload Repository （AWR）.
单项选择题 You issue the following RMAN command to set a retention policy on a database： RMAN>CONFIGURE RETENTION POLICY TO REDUNDANCY 2； What will be the outcome of issuing this command？（）
单项选择题 The BACKUP_TAPE_IO_SLAVES parameter is set to FALSE for the database instance. Which statement istrue while performing a tape backup in an RMAN session?（）
单项选择题 Examine the following ALTER command: SQL> ALTER DISKGROUP dgroup1 UNDROP DISKS; What is the purpose of the command?（）