I. Introduction
Big Data processing has emerged as one of the most promising solutions to next generation of analytics applications, most prominently, business analytics, monitoring systems, recommendation systems, etc. Inspite of being a new field of computing, Big Data processing comprises nowadays algorithmic solutions, especially after the Map-Reduce paradigm [6] as well as technological solutions based on Apache Hadoop. Yet, Big Data cannot address requirements of applications that need to consume data analytics in real time. This requirement can be addressed by Big Data Streams, that is, streams of data unbounded in time due a continuous data generation from a networked computing system. Indeed, by processing Big Data Streams we would be able to know in real time business analytics about business parameter performance, detect in real time fraudulent transactions, intrusion, etc. Examples of applications based on Big Data Stream processing include IoT systems, Virtual Campuses, Global Flight Monitoring, Online Transactions systems e.g. [4], [7] (refer to [18] for a description of Big Data Stream applications).