QUESTION 12
Examine the following command:
SQL> ALTER TABLE booking SHRINK SPACE COMPACT;
Which activity is performed when the preceding command is executed?
A. The shrink operation touches every block in the BOOKING table
B. The high-water mark (HWM) for the BOOKING table is shifted from its original position
C. The progress of the shrink operation is saved in the bitmap blocks of the BOOKING table
D. The data manipulation language (DML) triggers on the BOOKING table are executed because the shrink
operation is internally handled by the INSERT/DELETE operation
Answer: C
同96题：http://blog.csdn.net/rlhua/article/details/13772605
Explanation/Reference:
Section: SQL, PL/SQL, Packages, Functions, Jobs & Views
Based on the recommendations from the segment advisor you can recover space from specific objects using
one of the variations of the ALTER TABLE ... SHRINK SPACEcommands.
The shrink is accomplished by moving rows between blocks, hence the requirement for row movement to be
enabled for the shrink to take place. This can cause problem with ROWID based triggers. The shrinking
process is only available for objects in tablespaces with automatic segment-space management enabled.
The COMPACT option allows the shrink operation to be broken into two stages. First the rows are moved using
the COMPACToption but the HWM is not adjusted so no parsed SQLstatements are invalidated. The HWM can
be adjusted at a later date by reissuing the statement without the COMPACToption. At this point any
depenedant SQL statements will need to be reparsed.