Book Image

Learning Spark SQL

By : Aurobindo Sarkar
Book Image

Learning Spark SQL

By: Aurobindo Sarkar

Overview of this book

In the past year, Apache Spark has been increasingly adopted for the development of distributed applications. Spark SQL APIs provide an optimized interface that helps developers build such applications quickly and easily. However, designing web-scale production applications using Spark SQL APIs can be a complex task. Hence, understanding the design and implementation best practices before you start your project will help you avoid these problems. This book gives an insight into the engineering practices used to design and build real-world, Spark-based applications. The book's hands-on examples will give you the required confidence to work on any future projects you encounter in Spark SQL. It starts by familiarizing you with data exploration and data munging tasks using Spark SQL and Scala. Extensive code examples will help you understand the methods used to implement typical use-cases for various types of applications. You will get a walkthrough of the key concepts and terms that are common to streaming, machine learning, and graph applications. You will also learn key performance-tuning details including Cost Based Optimization (Spark 2.2) in Spark SQL applications. Finally, you will move on to learning how such systems are architected and deployed for a successful delivery of your project.
Table of Contents (19 chapters)
Title Page
Credits
About the Author
About the Reviewer
www.PacktPub.com
Customer Feedback
Preface

Using Naive Bayes classifiers


Naive Bayes classifiers are a family of probabilistic classifiers on applying the Bayes' conditional probability theorem. These classifiers assume independence between the features. Naive Bayes is often the baseline method for text categorization with word frequencies as the set. Despite the strong independence assumptions, the Naive Bayes classifiers are fast and easy to implement; hence, they are used very commonly in practice.

While Naive Bayes is very popular, it also suffers from errors that can lead to favoring of one class over the other(s). For example, skewed data can cause the classifier to favor one class over another. Similarly, the independence assumption can lead to erroneous classification weights that one class over another.

Note

For specific heuristics for dealing with problems associated with Naive Bayes classifers, refer to Tackling the Poor Assumptions of Naive Bayes Text Classifiers, by Rennie, Shih, et al at https://people.csail.mit.edu...