Book Image

MySQL 8 Cookbook

By : Karthik Appigatla
Book Image

MySQL 8 Cookbook

By: Karthik Appigatla

Overview of this book

MySQL is one of the most popular and widely used relational databases in the World today. The recently released MySQL 8 version promises to be better and more efficient than ever before. This book contains everything you need to know to be the go-to person in your organization when it comes to MySQL. Starting with a quick installation and configuration of your MySQL instance, the book quickly jumps into the querying aspects of MySQL. It shows you the newest improvements in MySQL 8 and gives you hands-on experience in managing high-transaction and real-time datasets. If you've already worked with MySQL before and are looking to migrate your application to MySQL 8, this book will also show you how to do that. The book also contains recipes on efficient MySQL administration, with tips on effective user management, data recovery, security, database monitoring, performance tuning, troubleshooting, and more. With quick solutions to common and not-so-common problems you might encounter while working with MySQL 8, the book contains practical tips and tricks to give you the edge over others in designing, developing, and administering your database effectively.
Table of Contents (20 chapters)
Title Page
Dedication
Packt Upsell
Contributors
Preface
Index

Checking index usage


In the preceding section, you learned about removing redundant and duplicate indexes. While designing an application, you might have thought about filtering a query based on a column and added index. But over a period of time, because of changes in the application, you might not need that index. In this section, you will learn about identifying those unused indexes.

There are two ways you can find unused indexes:

  • Using pt-index-usage (covered in this section)
  • Using sys schema (covered in the next section)

How to do it...

We can use the pt-index-usage tool from the Percona Toolkit to get the index analysis. It takes queries from the slow query log, runs the explain plan for each and every query, and identifies the unused indexes. If you have a list of queries, you can save them in slow query format and pass that to the tool. Note that this is only an approximation because the slow query log does not include all the queries:

shell> sudo pt-index-usage slow -u <user&gt...