（）involves comparing actual or planned project practices to those of other projects to generate ideas for improvement and to provide a basis by which to measure performance. These other projects can be within the performing organization or outside of it, and can be within the same or in another application area.

Immediately after adding a new disk to or removing an existing disk from an ASM instance, you find that the performance of the database goes down initially until the time the addition or removal process is completed, and then gradually becomes normal.
Which two activities would you perform to maintain a consistent performance of the database while adding or removing disks?（）

Consider the events_% tables in performance Schema.
Which two methods will clear or reset the collected events in the tables?（）

An index called ORD_CUSTNAME_IX has been created on the CUSTNAME column in the ORDERS table using the following command:
SQL>CREATE INDEX ord_custname_ix ON orders(custname);
The ORDERS table is frequently queried using the CUSTNAME column in the WHERE clause.
You want to check the impact on the performance of the queries if the index is not available. You do not want the index to be dropped or rebuilt to perform this test.Which is the most efficient method of performing this task?（）

the goods which have entered the territory,approved by the Customs as items for which no formalities are performed in the way of duty payment,and will be reshipped out of the territory after being stored,processed or assembled in the territory are defined as （）