Oracle 12c is the first release since a couple of years that adds significant new functionality in the area of Parallel Execution operators, plan shapes and runtime features. Although 11gR2 added the new Auto DOP feature along with In-Memory Parallel Execution and Statement Queueing, the 12c features are more significant because they introduce new operators that can change both execution plan shape and runtime behaviour.
Here is a list of new features that are worth to note (and not necessarily mentioned in the official documentation and white papers by Oracle):
- The new HYBRID HASH adaptive distribution method, that serves two purposes for parallel HASH and MERGE JOINs: