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

Using index hints


Using index hints, you can hint the optimizer to use or ignore indexes. This is different from optimizer hints. In optimizer hints, you hint the optimizer to use or ignore certain optimization methods. Index and optimizer hints can be used separately or together to achieve the desired plan. Index hints are specified following a table name. 

When you are executing a complex query involving multiple table joins, and if the optimizer is taking too much time in evaluating the plans, you can determine the best plan and give it a hint to the query. But make sure that the plan you are suggesting is the best and should work in all cases.

How to do it...

Take the same query where you evaluated the use of the redundant index as an example; it is using intersect(from_date,from_date_2). By passing the optimizer hint (/*+ NO_INDEX_MERGE(s from_date,from_date_2) */), you avoided the use of intersect. You can achieve the same behavior by hinting the optimizer to ignore the from_date_2 index...