QUESTION 149
You enable block change tracking. You issue the following command:
BACKUP INCREMENTAL LEVEL 0 DATABASE;
The next day, you issue the following command:
BACKUP INCREMENTAL LEVEL 1 CUMULATIVE DATABASE;
Which statement about the use of the change tracking file is true?
A. RMAN reads the block change tracking file only whenit performs the incremental level 0 backup.
B. RMAN reads the block change tracking file when it performs both incremental backups.
C. RMAN reads the block change tracking file only when it performs the incremental level 1 backup.
D. RMAN does not read the block change tracking file when it performs either incremental backup.
Answer: C
同78题：http://blog.csdn.net/rlhua/article/details/12362417
Explanation/Reference:
Section: Backup, Recovery & Recovery Manager (RMAN)
RMAN reads the block change tracking file only when it performs the incremental level 1 backup. After you
enable block change tracking, you perform a level 0incremental backup. For this backup, RMAN has to scan
the entire datafile because the change tracking file does not contain information about the changed blocks.
Next, you perform an incremental level 1 backup. For this backup, RMAN uses the block change tracking file to
determine the blocks that have changed since the incremental level 0 backup.
The option that states RMAN reads the block change tracking file only when it performs the incremental level 0
backup is incorrect. For the first incremental level 0 backup, the change tracking file does not contain
information about the changed blocks, and RMAN has to scan the entire datafiles to determine the blocksthat
have changed.
The option that states RMAN reads the block change tracking file when it performs both incremental backups is
incorrect. RMAN only uses the block change tracking file for the incremental level 1 backup.
The option that states RMAN does not read the block change tracking file when it performs either incremental
backup is incorrect. RMAN uses the block change tracking file for the incremental level 1 backup, but not for
the incremental level 0 backup.