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

Removing duplicate and redundant indexes


You can define several indexes on a column. By mistake, you might have defined the same index again (same column, same order of columns, or same order of keys), which is called a duplicate index. If only partial indexes (leftmost columns) are repetitive, they are called redundant indexes. A duplicate index has no advantages. Redundant indexes might be useful in some cases (a use case is mentioned in the note at the end of this section), but both slow down the inserts. So, it is important to identify and remove them.

There are three tools that can help with finding out duplicate indexes:

  • pt-duplicate-key-checker, which is part of the Percona Toolkit. Installing the Percona Toolkit is covered in Chapter 10Table MaintenanceInstalling Percona Toolkit section.
  • mysqlindexcheck, which is part of MySQL utilities. Installing MySQL utilities is covered in Chapter 1, MySQL 8.0 – Installing and Upgrading.
  • Using the sys schema, which will be covered in the next...