In this chapter, we first saw available the transformations on key/value pairs. We then learned how to use aggregateByKey instead of groupBy. We also covered actions on key/value pairs. Later, we looked at available partitioners like rangePartitioner and HashPartition on key/value data. By the end of this chapter, we had implemented our custom partitioner, which was able to assign partitions, based on the end and start of the range for learning purposes.

In the next chapter, we will learn how to test our Spark jobs and Apache Spark jobs.