MySQL8.4: Why Query Optimization Matters

Welcome to the MySQL 8.4 Indexing and Query Optimization course. In this course, we will learn how to identify inefficient SQL statements, understand how MySQL executes queries, design effective indexes, analyze execution plans, and improve performance using real-world examples. Imagine that you are supporting a production MySQL database. One day, users report that a web application is responding slowly. Some pages take several seconds to load, and database CPU utilization has increased significantly. What would you do first? Would you increase the server's memory, add more CPU cores, change the NODB buffer pool size, or create a new index? All of these actions might be appropriate in certain situations. But none should be your first decision without evidence. A slow application may be caused by an inefficient SQL statement, a missing index, excessive rows being examined, an expensive join, disk, I-O, lock contention, or a combination of these factors. Our goal is to learn how to identify the actual bottleneck and select the right solution. Throughout this course, we will use MySQL 8.4, practical SQL examples, execution plans, and performance measurements. Most importantly, we will learn to measure performance before and after every significant change. Let's begin.