off-heap

I thought that with the integration of project Tungesten, spark would automatically use off heap memory. What for are spark.memory.offheap.size and spark.memory.offheap.enabled? Do I manually need to specify the amount of off heap memory for Tungsten here? Spark/Tungsten use Encoders/Decoders to represent JVM objects as a highly specialized Spark SQL Types objects which then can be serialized and operated on in a highly performant way. Internal format representation is highly efficient and friendly to GC memory utilization. Thus, even operating in the default on-heap mode Tungsten alleviates