Which three statements are true about Flashback Database?
A.
Flashback logs are written sequentially, and are archived.
B.
Flashback Database uses a restored control file to recover a database.
C.
The Oracle database automatically creates, deletes, and resides flashback logs in the Fast Recovery Area.
D.
Flashback Database can recover a database to the state that it was in before a reset logs operation.
E.
Flashback Database can recover a data file that was dropped during the span of time of the flashback.
F.
Flashback logs are used to restore to the blocks’ before images, and then the redo data may be used to roll
forward to the desired flashback time.
Explanation:
* Flashback Database uses its own logging mechanism, creating flashback logs and storing them in the fast
recovery area (C). You can only use Flashback Database if flashback logs are available. To take advantage of
this feature, you must set up your database in advance to create flashback logs.
* To enable Flashback Database, you configure a fast recovery area and set a flashback retention target. This
retention target specifies how far back you can rewind a database with Flashback Database.
From that time onwards, at regular intervals, the database copies images of each altered block in every data file
into the flashback logs. These block images can later be reused to reconstruct the data file contents for any
moment at which logs were captured. (F)
Incorrect:
Not E: You cannot use Flashback Database alone to retrieve a dropped data file. If you flash back a database
to a time when a dropped data file existed in the database, only the data file entry is added to the control file.
You can only recover the dropped data file by using RMAN to fully restore and recover the data file.
The correct answers should be C, D, and F.
– To return the database to the point in time immediately before the most recent OPEN RESETLOGS operation, you use FLASHBACK DATABASE TO BEFORE RESETLOGS.
A is incorrect as Flashback logs are written sequentially, but are not archived.
B is incorrect.
– If the database control file is restored from backup or re-created, all accumulated flashback log information is discarded. You cannot use FLASHBACK DATABASE to return to a point in time before the restore or re-creation of a control file.