Oracle has introduced industry breakthrough enhancement in patch set 1 of existing database 12c, called In-Memory.
Traditionally, Oracle stores data in tables in form of rows. This new feature will allow to store data in memory in columnar format.
Storing data in columnar format give multiple times performance gain for DSS systems where you tend to retrieve fewer columns with multiple rows and this performance enhancement is further multiplied when you retrieve that data from memory instead of slower disks.