Book Image

Redis Essentials

Book Image

Redis Essentials

Overview of this book

Redis is the most popular in-memory key-value data store. It's very lightweight and its data types give it an edge over the other competitors. If you need an in-memory database or a high-performance cache system that is simple to use and highly scalable, Redis is what you need. Redis Essentials is a fast-paced guide that teaches the fundamentals on data types, explains how to manage data through commands, and shares experiences from big players in the industry. We start off by explaining the basics of Redis followed by the various data types such as Strings, hashes, lists, and more. Next, Common pitfalls for various scenarios are described, followed by solutions to ensure you do not fall into common traps. After this, major differences between client implementations in PHP, Python, and Ruby are presented. Next, you will learn how to extend Redis with Lua, get to know security techniques such as basic authorization, firewall rules, and SSL encryption, and discover how to use Twemproxy, Redis Sentinel, and Redis Cluster to scale infrastructures horizontally. At the end of this book, you will be able to utilize all the essential features of Redis to optimize your project's performance.
Table of Contents (11 chapters)
5
5. Clients for Your Favorite Language (Become a Redis Polyglot)
10
Index

Pipelines


In Redis, a pipeline is a way to send multiple commands together to the Redis server without waiting for individual replies. The replies are read all at once by the client. The time taken for a Redis client to send a command and obtain a reply from the Redis server is called Round Trip Time (RTT). When multiple commands are sent, there are multiple RTTs.

Pipelines can decrease the number of RTTs because commands are grouped, so a pipeline with 10 commands will have only one RTT. This can improve the network's performance significantly.

For instance, if the network link between a client and server has an RTT of 100 ms, the maximum number of commands that can be sent per second is 10, no matter how many commands can be handled by the Redis server. Usually, a Redis server can handle hundreds of thousands of commands per second, and not using pipelines may be a waste of resources.

When Redis is used without pipelines, each command needs to wait for a reply. Assume the following:

var redis...