Blocker Description
From what I commented at the tail of HBASE-4027:
I changed the release note, the patch doesn't have a "hbase.offheapcachesize" configuration and it's enabled as soon as you set -XX:MaxDirectMemorySize (which is actually a big problem when you consider this: http://hbase.apache.org/book.html#trouble.client.oome.directmemory.leak).
We need to add hbase.offheapcachesize and set it to false by default.
Marking as a blocker for 0.92.1 and assigning to Li Pi at Todd's request.