Users of the Exadata Cloud Service (ExaCS)—well, Exadata in general—have enjoyed the ability to use multiple compression techniques for many, many years. Utilizing the CPUs in the storage cells, a lot of the compress/decompress work is done in the back end. In this chapter, we will start with the basics: how Oracle stores data. This is important information, because many of the concepts that you’ll learn about compression refer to the basic storage concepts of the Oracle Database. After the overview, we will work with five compression techniques you can use on the ExaCS for various types of data.