Through this article, we are going to complete the MapReduce job started in the [previous article](https://www.2ndquadrant.com/en/2011/10/mapreduce-in-greenplum.html).
Mapreduce is a very trendy software framework. It has been introduced by Google (TM) in 2004. It is a large topic, and it is not possible to cover all of its aspetcs in a single blog article. This is a simple introduction to the _mapreduce_ usage in Greenplum 4.1.