Flags for controlling the storage of an RDD. Each StorageLevel records whether to use memory,
whether to drop the RDD to disk if it falls out of memory, whether to keep the data in memory
in a serialized format, and whether to replicate the RDD partitions on multiple nodes.
The spark.storage.StorageLevel$ singleton object contains some static constants for
commonly useful storage levels. To create your own storage level object, use the factor method
of the singleton object (StorageLevel(...)).
Flags for controlling the storage of an RDD. Each StorageLevel records whether to use memory, whether to drop the RDD to disk if it falls out of memory, whether to keep the data in memory in a serialized format, and whether to replicate the RDD partitions on multiple nodes. The spark.storage.StorageLevel$ singleton object contains some static constants for commonly useful storage levels. To create your own storage level object, use the factor method of the singleton object (
StorageLevel(...)).