OCP-1Z0-053-V12.02-595题

595.Which dynamic view displays the status of block-change tracking?

A. V$BLOCK_CHANGE

B. V$BLOCK_CHANGE_TRACKING

C. V$BLOCKCHANGE

D. V$BLOCK_TRACKING

Answer: B

答案解析：

V$BLOCK_CHANGE_TRACKING displays the status of block change tracking for the database.

Status of block change tracking in the database:

• DISABLED - Block change tracking is disabled

• TRANSITION - Block change tracking is in the process of transitioning between the enabled and disabled states. The TRANSITION state should usually never be observed, because it only exists while enabling or disabling block change tracking. This state might be observed if the instance crashed while enabling or disabling block change tracking, in which case it will be cleaned up automatically the next time that the database is opened.

• ENABLED - Block change tracking is enabled

官方参考：http://docs.oracle.com/cd/E16655_01/server.121/e17615/refrn30030.htm#REFRN30030

Checking Whether Change Tracking Is Enabled

You can query the V$BLOCK_CHANGE_TRACKING  view to determine whether change tracking is enabled, and if it is, the file name of the block change tracking file.

To determine whether change tracking is enabled:

Enter the following query in SQL*Plus (sample output included):

COL STATUS   FORMAT A8

COL FILENAME FORMAT A60

SELECT STATUS, FILENAME

FROM   V$BLOCK_CHANGE_TRACKING;

STATUS   FILENAME

-------- ------------------------------------------------------------

ENABLED  /disk1/bct/RDBMS/changetracking/o1_mf_2f71np5j_.chg

 

官方参考：http://docs.oracle.com/cd/E16655_01/backup.121/e17630/rcmbckba.htm#BRADV8125