What this book covers

Chapter 1, Introduction to Apex, tells us how processing of data-in-motion is realized by Apache Apex. It also gives us a few Apex stream processing use cases and applications, and talks about their value propositions.

Chapter 2, Getting Started with Application Development, shows us how the Apex development process works from project creation to application deployment; the result is a simple working application.

Chapter 3, The Apex Library, talks about the Malhar library, which contains functional building blocks for writing real-world Apex applications.

Chapter 4, Scalability, Low Latency, and Performance, teaches us how Apex can scale and parallize processing, how to achieve dynamic scaling and better resource allocation in general, and why low latency and high throughput are both achievable without trading one off against the other. Operator partitioning and related techniques are central to this endeavor and are shown in practice in a sample application.

Chapter 5, Fault Tolerance and Reliability, explores the implementation of fault-tolerance and reliability in Apex including exactly-once semantics via distributed checkpointing and effective state management.

Chapter 6, Example Project – Real-Time Aggregation and Visualization, puts together all the building blocks to show a streaming analytics project and how to integrate it with a UI and existing infrastructure.

Chapter 7, Example Project – Real-Time Ride Service Data Processing, relies on a historical dataset to simulate a real-time ride service data stream. We are using event time and out-of-order processing, in particular, to build a simple analytics application that can serve as a template for more complicated event stream data pipelines.

Chapter 8, Example Project – ETL Using SQL, shows how to build a classic ETL application using Apex and Apache Calcite.

Chapter 9, Introduction to Apache Beam, introduces the Beam stream processing framework and an approach that allows a stream application engine such as Apex to be swapped in if needed.

Chapter 10, The Future of Stream Processing, looks at the road ahead for Apex and stream processing in general. We are going to examine the role of machine learning, as well as the role of SQL and why it is important for streaming.