apache/spark — pull request #1083 by andrewor14 (2014-06-14 04:12:04+00:00)
Title: [SPARK-1201] Do not fully materialize partitions for StorageLevel.MEMORY_*_SER

The deserialized version of a partition may occupy much more space than the serialized version. Therefore, if a partition is to be cached with `StorageLevel.MEMORY_*_SER`, we don't need to fully unroll it into an `ArrayBuffer`, but instead we can unroll it into a potentially much smaller `ByteBuffer`.