Umbrella jira to make sure we can have blocks cached in offheap backed cache. In the entire read path, we can refer to this offheap buffer and avoid onheap copying.
The high level items I can identify as of now are
1. Avoid the array() call on BB in read path.. (This is there in many classes. We can handle class by class)
2. Support Buffer based getter APIs in cell. In read path we will create a new Cell with backed by BB. Will need in CellComparator, Filter (like SCVF), CPs etc.
3. Avoid KeyValue.ensureKeyValue() calls in read path - This make byte copy.
4. Remove all CP hooks (which are already deprecated) which deal with KVs. (In read path)
Will add subtasks under this.