Spark Streaming questions, just 2

[shyla deshpande]

Hello all,
I have a couple of spark streaming questions. Thanks.

1.  In the case of stateful operations, the data is, by default,
persistent in memory.
    In memory does it mean MEMORY_ONLY?   When is it removed from memory?

2.   I do not see any documentation for spark.cleaner.ttl. Is this no
longer necessary? (SPARK-7689)