Book Image

Practical Real-time Data Processing and Analytics

Book Image

Practical Real-time Data Processing and Analytics

Overview of this book

With the rise of Big Data, there is an increasing need to process large amounts of data continuously, with a shorter turnaround time. Real-time data processing involves continuous input, processing and output of data, with the condition that the time required for processing is as short as possible. This book covers the majority of the existing and evolving open source technology stack for real-time processing and analytics. You will get to know about all the real-time solution aspects, from the source to the presentation to persistence. Through this practical book, you’ll be equipped with a clear understanding of how to solve challenges on your own. We’ll cover topics such as how to set up components, basic executions, integrations, advanced use cases, alerts, and monitoring. You’ll be exposed to the popular tools used in real-time processing today such as Apache Spark, Apache Flink, and Storm. Finally, you will put your knowledge to practical use by implementing all of the techniques in the form of a practical, real-world use case. By the end of this book, you will have a solid understanding of all the aspects of real-time data processing and analytics, and will know how to deploy the solutions in production environments in the best possible manner.
Table of Contents (20 chapters)
Title Page
Credits
About the Authors
About the Reviewers
www.PacktPub.com
Customer Feedback
Preface

Shared variables – broadcast variables and accumulators


While working in distributed compute programs and modules, where the code executes on different nodes and/or different workers, a lot of time a need arises to share data across the execution units in the distributed execution setup. Thus Spark has the concept of shared variables. The shared variables are used to share information between the parallel executing tasks across various workers or the tasks and the drivers. Spark supports two types of shared variable:

  • Broadcast variables
  • Accumulators

In the following sections, we will look at these two types of Spark variables, both conceptually and pragmatically.

Broadcast variables

These are the variables that the programmer intends to share to all execution units throughout the cluster. Though they sound very simple to work with, there are a few aspects the programmers need to be cognizant of while working with broadcast variables: they need to be able to fit in the memory of each node in the...