Which four statements regarding the block change track file are correct?
A.
The minimum size of this file is 10MB
B.
The maintenance of this file is fully automatic.
C.
The changed block are tracked in this fils as redo is generated
D.
The location of this file must be different from that of the database files.
E.
The Oracle database records block change information in this file by default
Explanation:
– True. Should say “start” not “minimum”.The size of the change tracking file is proportional to the size of the database and the number of enabled threads of redo. The size is not related to the frequency of updates to the database. Typically, the space required for block change tracking is Overview of Reporting on Backups and the RMAN Repository approximately 1/30,000 the size of the data blocks to be tracked. Note, however, the following two factors that may cause the file to be larger than this estimate suggests:
? To avoid overhead of allocating space as your database grows, the change tracking file size starts at 10MB, and new space is allocated in 10MB increments; ? For each datafile, a minimum of 320K of space is allocated in the change tracking file, regardless of the size of the file.
B – True. Change tracking is disabled by default, because it does introduce some minimal performance overhead on your database during normal operations. Although RMAN does not support backup and recovery of the change-tracking file itself, if the whole database or a subset needs to be restored and recovered, then recovery has no user-visible effect on change tracking. After the restore and recovery, the change tracking file is cleared, and starts recording block changes again. The next incremental backup after any recovery is able to use change-tracking data.
C – True. Changed blocks are tracked by the CTWR background process as redo is generated. Database incremental backups, automatically use the change tracking file; D – False. By default, the change tracking file is created as an Oracle managed file in DB_CREATE_FILE_DEST. You can also specify the name of the block change tracking file, placing it in any location you choose. You can also change the location of the change tracking file while preserving its contents.
E – True. One change tracking file is created for the whole database. RMAN’s change tracking feature for incremental backups improves incremental backup performance by recording changed blocks in each datafile in a change tracking file. REF.: Oracle(r) Backup and Recovery Basics 10g – BASICS , 4-19, 4-20 and 4-21