Which statements are true regarding table compression? (Choose all that apply.)
A. It saves disk space and reduces memory usage.
B. It saves disk space but has no effect on memory usage.
C. It incurs extra CPU overhead during DML as well as direct loading operations.
D. It incurs extra CPU overhead during DML but not direct loading operations.
E. It requires uncompress operation during I/O.
原文：http://www.cnblogs.com/Babylon/p/7845286.html