Hive just added Decimal64ColumnVector for faster operations on decimal objects that are <= 18 digits of precision.
- We create a new method in TypeDescription to create the VectorizedRowBatch with the new Decimal64ColumnVector.
- Have the reader and writer detect the ColumnVector type and call the right internal method.
This leaves current clients working using the current ColumnVector. Clients can chose when to transition to the new interface.