Remove Empty Partitions from Spark RDD
There isn't an easy way to simply delete the empty partitions from a RDD.
coalesce doesn't guarantee that the empty partitions will be deleted. If you have a RDD with 40 blank partitions and 10 partitions with data, there will still be empty partitions after rdd.coalesce(45).
The repartition method splits the data evenly over all the partitions, so there won't be any empty partitions. If you have a RDD with 50 blank partitions and 10 partitions with data and run rdd.repartition(20), the data will be evenly split across the 20 partitions.