In this chapter, we discussed the partitioning of operators and how it is the key platform feature that provides both static scalability and adaptive dynamic scalability to Apex applications with minimal required effort on the part of the application writer. We discussed related concepts such as shuffled partitioning, parallel partitioning, unifiers, and stream codecs, how these features can be configured either in code or in properties files and how the interplay of these features results in unparalleled flexibility and outstanding run-time performance. Finally, we concluded by discussing a sample application that illustrates some of these features.
In the next chapter, we will cover another key strength of Apex: fault tolerance and reliability with check-pointing and processing guarantees.