In the first post
[https://www.rittmanmead.com/blog/2014/12/going-beyond-mapreduce-for-hadoop-etl-pt-1-why-mapreduce-is-only-for-batch-processing/]
in this three part series on going beyond MapReduce for Hadoop ETL, I looked at
how a typical Apache Pig script gets compiled into a series of MapReduce jobs,
and those MapReduce jobs pass data between themselves by