Your database instance is running with full workload after database creation. You have decided to
use a fixed-size undo tablespace. You want to use the undo Advisor to estimate the capacity of the
undo tablespace. Which two factors must you consider before using the Undo Advisor to estimate
the capacity of the undo tablespace? (Choose two.)
A.
The retention period to support flashback
B.
The expected length of the longest-running query
C.
The number of undo tablespaces in the database
D.
The size of the Flash Recovery Area for the database instance
You specify the minimum undo retention period (in seconds) by setting the UNDO_RETENTION initialization parameter.
Sizing a Fixed-Size Undo Tablespace
Automatic tuning of undo retention typically achieves better results with a fixed-size undo tablespace. If you decide to use a fixed-size undo tablespace, the Undo Advisor can help you estimate needed capacity. You can access the Undo Advisor through Enterprise Manager or through the DBMS_ADVISOR PL/SQL package. Enterprise Manager is the preferred method of accessing the advisor
To use the Undo Advisor, you first estimate these two values:
1. The length of your expected longest running query
2. The longest interval that you will require for Oracle Flashback operations