Which statement about recovering from the loss of a redo log group is true?
A.
If the lost redo log group is ACTIVE, you should first attempt to clear the log file.
B.
If the lost redo log group is CURRENT, you must clear the log file.
C.
If the lost redo log group is ACTIVE, you must restore, perform cancel-based incomplete
recovery, and open
the database using the RESETLOGS option.
D.
If the lost redo log group is CURRENT, you must restore, perform cancel-based incomplete
recovery, and open the database using the RESETLOGS option.
Explanation:
If the lost redo log group is CURRENT, you must restore, perform cancel-based incomplete
recovery, and open the database using the RESETLOGS option. A redo log group with a
CURRENT status indicates that LGWR is currently writing to it. To recover from this failure, you
must restore the database from a whole backup and perform cancel-based incomplete recovery.
Then, you should open the database using the RESETLOGS option. The option that states if the
lost redo log group is ACTIVE, you should first attempt to clear the log file is incorrect. If the lost
redo log group has a status of ACTIVE, it is needed for instance recovery. In that situation, you
should first attempt to perform a checkpoint. After the checkpoint, the log file is no longer required
for instance recovery. The option that states if the lost redo log group is CURRENT, you must
clear the log file is incorrect. You would clear the log file only if the status of the lost redo log group
was INACTIVE. After clearing the log file, the log file may be reused. The option that states if the
lost redo log group is ACTIVE, you must restore, perform cancel-based incomplete recovery, andopen the database using the RESETLOGS option. These actions are only necessary if the log file
has a CURRENT status, which indicates LGWR is currently writing to it.