Book Image

Redis 4.x Cookbook

Book Image

Redis 4.x Cookbook

Overview of this book

Redis is considered the world's most popular key-value store database. Its versatility and the wide variety of use cases it enables have made it a popular choice of database for many enterprises. Based on the latest version of Redis, this book provides both step-by-step recipes and relevant the background information required to utilize its features to the fullest. It covers everything from a basic understanding of Redis data types to advanced aspects of Redis high availability, clustering, administration, and troubleshooting. This book will be your great companion to master all aspects of Redis. The book starts off by installing and configuring Redis for you to get started with ease. Moving on, all the data types and features of Redis are introduced in detail. Next, you will learn how to develop applications with Redis in Java, Python, and the Spring Boot web framework. You will also learn replication tasks, which will help you to troubleshoot replication issues. Furthermore, you will learn the steps that need to be undertaken to ensure high availability on your cluster and during production deployment. Toward the end of the book, you will learn the topmost tasks that will help you to troubleshoot your ecosystem efficiently, along with extending Redis by using different modules.
Table of Contents (21 chapters)
Title Page
Packt Upsell
Windows Environment Setup

Using bitmaps

A bitmap (also known as a bit array, or bit vector) is an array of bits. A Redis bitmap is not a new data type; its actual underlying data type is string. Since a string is inherently a binary blob, it can be viewed as a bitmap. A bitmap saves enormous memory space for storing boolean information under certain circumstances.

In this recipe, we will use a bitmap to store a flag, whether or not a user has ever used a feature in Relp. Suppose that in Relp every user has a unique and incremental id, which can be denoted by the bitmap offset. The flag, which is a boolean attribute, can be denoted by the bit value in the bitmap.

Getting ready…

You need to finish the installation of the Redis Server as we described in the Downloading and installing Redis recipe in Chapter 1, Getting Started with Redis.

How to do it…

The steps for using bitmaps are as follows:

  1. Open a Terminal and connect to Redis with redis-cli
  2. Use SETBIT to set the bit value in a bitmap at the specified offset.

For example...