Shantanu Kumar - Clojure High Performance Programming

Shantanu Kumar is a software developer living in Bengaluru, India. He works with Concur Technologies as a principal engineer, building a next-generation stack in Clojure. He started learning computer programming when he was at school, and has dabbled in several programming languages and software technologies. Having used Java for a long time, he discovered Clojure in early 2009 and has been a fan of it ever since.

When not busy with programming or reading up on technical stuff, he enjoys reading non-fiction and cycling around Bengaluru. Shantanu is an active participant in The Bangalore Clojure Users Group, and contributes to several open source Clojure projects on GitHub. He is also the author of the first edition of the book Clojure High Performance Programming , Packt Publishing .

I am grateful to my colleagues, Saju Pillai and Vijay Mathew, at Concur India for imparting marathon performance analysis/tuning sessions. I appreciate the input received from Andy Fingerhut and Zach Tellman on certain topics during the course of writing the second edition of the book. I also want to thank the technical reviewers and the team at Packt for their valuable input and support.

Writing this book has been an arduous task. I want to thank my family for putting up with me while I was immersed in this book for far too many days and weekends. If not for their support, I would not have been able to do justice to the book.

Eduard Bondarenko is a software developer living in Kiev, Ukraine. He started programming using Basic on ZXSpectrum a long time ago. Later, he worked professionally in the web development domain.

Eduard used Ruby on Rails for many years. Having used Ruby for a long time, he discovered Clojure in early 2009 and liked the language. Besides Ruby and Clojure, he is also interested in Erlang, Scala languages, machine learning, and logic programming.

Matjaz Gregoric is a software developer living in Ljubljana, Slovenia, with his wife and two children. He has a BS degree in physics, and has been developing software professionally since 2007.

During his career, Matjaz worked on various projects where he was able to get familiar with different technologies and programming languages. In 2010, he got familiar with Clojure and immediately fell in love with it. He is currently working on scalable distributed systems and complex web UIs.

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Preface

Since the first edition of this book was published in November 2013, Clojure has seen a much wider adoption and has witnessed many success stories. The newer versions of Clojure fortify its performance story while staying close to its rootssimplicity and pragmatism. This edition significantly updates the book for Clojure 1.7, and adds a new chapter on the performance measurement.

The Java Virtual Machine plays a huge role in the performance of the Clojure programs. This edition of the book increases the focus on the JVM tools for performance management, and it explores how to use those. This book is updated to use Java 8, though it also highlights the places where features from Java 7 or 8 have been used.

This book is updated mainly to be more of practical use to the readers. I hope that this edition will better equip the readers with performance measurement and profiling tools and with the know-how of analyzing and tuning the performance characteristics of Clojure code.

What this book covers

, Performance by Design , classifies the various use cases with respect to performance, and analyzes how to interpret their performance aspects and needs.

, Clojure Abstractions , is a guided tour of various Clojure data structures, abstractions (persistent data structures, vars, macros, transducers, and so on), and their performance characteristics.

, Leaning on Java , discusses how to enhance performance by using Java interoperability and features from Clojure.

, Host Performance , discusses how the host stack impacts performance. Being a hosted language, Clojure has its performance directly related to the host.