Apache Cassandra Essentials

Table of Contents

Apache Cassandra Essentials

Credits

About the Author

About the Reviewers

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Preface

What this book covers

What you need for this book

Who this book is for

Conventions

Reader feedback

Customer support

Downloading the example code

Errata

Piracy

Questions

1. Getting Your Cassandra Cluster Ready

Installation

Prerequisites

Compiling Cassandra from source and installing

Installation from a precompiled binary

The installation layout

The directory layout in tarball installations

The directory layout in package-based installation

Configuration files

cassandra.yaml

Running a Cassandra server

Running a Cassandra node

Setting up the cluster

Viewing the cluster status

Summary

2. An Architectural Overview

Background

Cassandra cluster overview

The Gossip protocol

Failure detection

Data distribution

Replication

SimpleStrategy

NetworkTopologyStrategy

Snitches

Virtual nodes

Adding nodes to our cluster

Create keyspace and column family

Summary

3. Creating Database and Schema

A database and schema

Keyspace

Column families

Static rows

Wide rows

A primary key

Partition keys and clustering columns

A composite partition key

Multiple clustering columns

Static columns

Modifying a table

Data types

Counters

Collections

Sets

Lists

Map

UDTs

Secondary indexes

Allowing filtering

TTL

Conditional querying

Conditions on a partition key

Conditions on a partition key and clustering columns

Sorting query results

Write operations

Lightweight transactions

Batch statements

Summary

4. Read and Write – Behind the Scenes

Write operations

CommitLog

Anatomy of Memtable

SSTable explained

SSTable Compaction strategies

Size-tiered compaction

Leveled compaction

DateTiered compaction

Read operations

Reads from row cache

Read operations for row cache miss

Key is in KeyCache

Key search miss both the key cache and the row cache

Delete operations

Data consistency

Read operation

Digest reads

Read repair

Consistency levels

Write operation

Hinted handoff

Consistency levels

Tracing Cassandra queries

Summary

5. Writing Your Cassandra Client

Connecting to a Cassandra cluster

Driver Connection policies

Load balancing policies

Retry policies

Reconnection policies

Reading and writing to the Cassandra cluster

QueryBuilder

Reading and writing asynchronously

Prepared statements

Example REST service using prepared statement

Batch statements

Mapping API

Tracing Cassandra queries using Java driver

Summary

6. Monitoring and Tuning a Cassandra Cluster

Monitoring a Cassandra cluster

Use logging for debugging

Monitoring using command-line utilities

nodetool cfstats

nodetool cfhistograms

nodetool netstats

nodetool tpstats

JConsole

Third-party tools

Tuning Cassandra nodes

Configuring Cassandra caches

Tuning Bloom filters

Configuring and tuning Java

Summary

7. Backup and Restore

Taking backup of a Casandra cluster

Manual backup

Deleting snapshots

Incremental backup

Restoring data to Cassandra

The Cassandra bulk loader

Exporting and importing data using the Cassandra JSON utility

Loading external data into Cassandra

Removing nodes from Cassandra cluster

Adding nodes to a Cassandra cluster

Replacing dead nodes in a cluster

Summary

Index

Apache Cassandra Essentials

Apache Cassandra Essentials

Copyright © 2015 Packt Publishing

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Every effort has been made in the preparation of this book to ensure the accuracy of the information presented. However, the information contained in this book is sold without warranty, either express or implied. Neither the author, nor Packt Publishing, and its dealers and distributors will be held liable for any damages caused or alleged to be caused directly or indirectly by this book.

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First published: November 2015

Production reference: 1161115

Published by Packt Publishing Ltd.

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ISBN 978-1-78398-910-2

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Credits

Author

Nitin Padalia

Reviewers

Ranjeet Kumar Jha

Sonal Raj

Chaoran Yu

Commissioning Editor

Akram Hussain

Acquisition Editor

Meeta Rajani

Content Development Editor

Aparna Mitra

Technical Editor

Rohan Uttam Gosavi

Copy Editor

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Project Coordinator

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Proofreader

Safis Editing

Indexer

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Graphics

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Production Coordinator

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Cover Work

Nilesh Mohite

About the Author

Nitin Padalia is the technical leader at Aricent Group, where he is involved in building highly scalable distributed applications in the field of telecommunications. From the beginning of his career, he has been working in the field of telecommunications and has worked on protocols such as SMPP, RTP, SIP, and VOIP. Since the beginning of his career, he has worked on the development of applications that can scale infinitely with highest performance possible. He has experience of developing applications for bare metal hardware, virtualized environments, and cloud-based applications using various languages and technologies.

I would like to thank all the reviewers of this book; their comments helped me to present data effectively.

Meeta Rajani, for setting things up and providing input during the initial phase of the book.

Anish Sukumaran, for helping me through his comments and input till the completion of this book.

Chaoran Yu, for good suggestions regarding presenting data and examples in a way that could be more helpful from the readers' perspective.

Ranjit, for his input throughout the book.

I also would like to thank my family—my mother, father, wife, and kids—for letting me take some time out to write this book.

About the Reviewers

Ranjeet Kumar Jha has over 12 years (three years in the big data field) of experience in various phases of the project life cycle, including the development and design phases. He has also been part of production support for Java/JEE and big data-based applications. He is a certified enterprise architect, that is, Oracle Certified Master Enterprise Java JEE Architect, and has worked for over six years as an architect in Java JEE technologies (over three years in the big data field). He has worked in various domains such as finance, insurance, e-commerce, digital media, CMS, security, and online advertisements.

He has worked as a programmer, designer, mentor, and architect on all types of projects related to Java, especially JEE and big data. He is the reviewer of the book Real-time Analytics with Storm and Cassandra.

To find out more about him, visit his LinkedIn profile at https://www.linkedin.com/in/jharanjeet.

I would like to thank my family—my wife, Anila Jha, and two kids, Anushka Jha and Tanisha Jha, for their constant support, encouragement, and patience. Without you, I wouldn't have achieved so much! Love you all immensely.

Sonal Raj is a hacker, Pythonista, big data believer, and a technology dreamer. He has a passion for design and is an artist at heart. He blogs about technology, design, and gadgets at http://www.sonalraj.com/. When not working on projects, he can be found travelling, stargazing, or reading.

He has pursued engineering in computer science and holds a master's degree in IT. He loves to work on community projects. He has been a research fellow at IISc and has taken up projects on graph computations using Neo4j, Storm, and NoSQL databases. He has been a speaker at PyCon India and local meetups and has also published articles and research papers in leading magazines and international journals. He has contributed to several open source projects.

He is the author of Neo4j High Performance, Packt Publishing, and has reviewed titles on technologies such as Storm and Neo4j

I am grateful to the author for patiently listening to my critiques. I'd like to thank the open source community for keeping their passions alive and contributing to such remarkable projects. A special thank you to my parents, without whom I never would have grown to love learning as much as I do.

Chaoran Yu obtained his bachelor's degree with high honors from UC Berkeley Department of Electrical Engineering and Computer Science in May 2014. He has been a software developer with the data analytics team of Ericsson MediaFirst, a leading IPTV solution, since then. The technologies that he has worked on include Apache Cassandra, Spark, and the Microsoft .NET framework. He organized service and client logging and performance data and wrote code to store them in Cassandra, which he then processed with Spark jobs to generate real-time reports for TV operators. His passion for open source technologies, especially for distributed and scalable systems, makes him an avid learner in this ever-changing technology landscape.

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Preface

Traditional database management systems sometimes become the bottleneck of being highly available, scalable, and ultra responsive for modern day applications, as they are not able to satisfy the storage and retrieval needs of modern applications with all these attributes. Apache Cassandra being a highly available, massively scalable, NoSQL, query-driven database helps our applications to achieve these modern day must have attributes. Apache Cassandra's core features include handling of large data with the flexibility of configuring responsiveness, scalability, and high availability at the same time to suit our requirements.

In this book, I've provided step-by-step information starting from the basic installation to the advanced installation options and database design techniques. It gives all the information that you will need to design a well-distributed and high performance database. This book focuses on explaining core concepts with simple and easy-to-understand examples. I've also incorporated some code examples with this book. You can use these examples while working on your day-to-day tasks with Cassandra.

What this book covers

Chapter 1, Getting Your Cassandra Cluster Ready, gives an introduction to Cassandra and helps you to set up your cluster. It also introduces you to the various configuration options available to set up your cluster, which can be referred to while fine tuning the cluster.

Chapter 2, An Architectural Overview, helps you to understand the internal architecture of a Cassandra cluster. It details various strategies used by Cassandra to distribute data among various nodes in the cluster. It describes how Cassandra becomes highly available by employing various replication strategies. It also clarifies various replication and data distribution strategies.

Chapter 3, Creating Database and Schema, details the concepts used by Cassandra. We'll learn to use CQL (Cassandra Query Language), which is used by Cassandra clients to describe data models, to create our databases and tables. Also, we'll discuss various techniques provided by Cassandra that can be used based on our storage and data retrieval requirements.

Chapter 4, Read and Write – Behind the Scenes, has been written keeping in mind how the reader can understand core concepts of a system. We'll discuss the operations that Cassandra performs for every read and write query along with all the data structures and caches it uses. We'll also discuss what configuration options it provides to configure the trade-off between consistency and latency. In the later parts of this chapter, we'll see how we can trace a Cassandra read/write query to debug performance issues for our read/write queries.

Chapter 5, Writing Your Cassandra Client, provides some code samples to set up your cluster, learn the core concepts of Cassandra, and create