OCP 1Z0 053 72

72.You have 100 segments in the USERS tablespace. You realize that the USERS tablespace is running 
low on space. 
You can use Segment Advisor to _____. 
A. identify the segments that you should shrink 
B. modify the storage parameters for the tablespace 
C. automatically shrink the segments with unused space 
D. check the alerts generated for the tablespace that is running low on space 
Answer: A 

Segment Advisor 只能建议，不会更改。

http://docs.oracle.com/cd/E11882_01/server.112/e25494/schema.htm#ADMIN11601

Using the Segment Advisor

The Segment Advisor identifies segments that have space available for reclamation. It performs its analysis by examining usage and growth statistics in the Automatic Workload Repository (AWR), and by sampling the data in the segment. It is configured to run during maintenance windows as an automated maintenance task, and you can also run it on demand (manually). The Segment Advisor automated maintenance task is known as the Automatic Segment Advisor.

The Segment Advisor generates the following types of advice:

• If the Segment Advisor determines that an object has a significant amount of free space, it recommends online segment shrink. If the object is a table that is not eligible for shrinking, as in the case of a table in a tablespace without automatic segment space management, the Segment Advisor recommends online table redefinition.

• If the Segment Advisor determines that a table could benefit from compression with the OLTP compression method, it makes a recommendation to that effect. (Automatic Segment Advisor only. See "Automatic Segment Advisor".)

• If the Segment Advisor encounters a table with row chaining above a certain threshold, it records that fact that the table has an excess of chained rows.