A. Lists all datafiles created in the last three days that are not backed up.
B. Lists all datafiles not recoverable based on the current retention criteria.
C. Lists all datafiles not backed up in the last three days. The datafile is not recoverable. 
D. Lists all datafiles that need to be backed up due to unrecoverable operations.
E. Lists all datafiles not backed up in the last three days. It does not imply that the datafile is not recoverable.

A. The my_data_01.dbf datafile is corrupted and needs to be restored.
B. The my_data_01.dbf datafile has not yet been backed up. This report does not imply that the data in the datafile can not be recovered.
C. The my_data_01.dbf datafile has not yet been backed up. This report implies that the data in the datafile can not be recovered.
D. The my_data_01.dbf datafile no longer meets the retention criteria for backups.
E. Datafile 5 is missing.

A. There are no backup sets with any backups of the users01.dbf datafile.
B. The users01.dbf datafile has had unrecoverable operations occur in it. It will need to be backed up or some data loss is possible during a recovery.
C. The users01.dbf datafile is corrupted.
D. The users01.dbf datafile backup exceeds the retention criteria.
E. The last backup of the users01.dbf datafile failed and must be rerun.

A. V$SESSION_EVENT
B. V$SESSION
C. V$WAITS
D. V$WAITSTAT
E. V$SESSION_LONGOPS

A. V$SESSION_EVENT
B. V$SESSION
C. V$WAITS
D. V$WAITSTAT
E. V$SYSSTAT

A. The entire backup will fail.It will not be usable for recovery.
B. The entire backup will failbut any datafile successfully backed up will be usable for recovery.
C. If this backup fails，subsequent backups will prioritize datafiles not backed up.
D. If this backup fails，an error will be raised and any other commands will not be executed. 
E. If this backup fails，no error will be raised and any other commands will be executed.

A. 2 minutes
B. 2 hours
C. 2 days
D. The command will generate an error.
E. This backup is not constrained by any time limitation.

A. Change the retention criteria.
B. Make the lost backup set pieces available to RMAN again.
C. Run the crosscheck command to correct the location for the backup set piece contained in the metadata.
D. Nothing. The backup set piece is lost forever.
E. Call Oracle support，their assistance is required.

A. The backup set has exceeded the retention criteria set in RMAN and is eligible for removal. 
B. The backup set has one or more invalid blocks in it and is not usable for recovery.
C. The backup set contains one or more tablespaces no longer in the database.
D. The backup set contains one or more missing backup set pieces.
E. The backup set is from a previous version of RMAN and was not upgraded.

A. To remove missing backup set pieces physically from disk
B. To remove metadata related to backup set pieces in the control file and the recovery catalog
C. To mark as deleted records in the control file and the recovery catalog associated with obsolete backup sets
D. To delete backup set pieces associated with backups that are no longer needed due to retention criteria
E. To remove old versions of RMAN backups