Monitoring and Troubleshooting Rapid Database Growth in MySQL: A Guide to Managing Disk I/O

Ever experienced sudden slowdowns or unforeseen performance hiccups in your MySQL database? Disk I/O often becomes a crucial performance factor as databases grow and traffic increases. An effective way to manage this is by closely monitoring the most active databases and tables. This blog will introduce a tailor-made SQL script for MySQL 8 that helps identify rapidly growing databases and tables, explicitly focusing on Disk I/O.

Growth is a sign of success

For any application, growth is a sign of success. However, when it comes to databases, it can also present unique challenges. When your MySQL database starts to grow rapidly, managing Disk I/O becomes increasingly critical. With the right tools at your disposal, you can easily monitor this growth and ensure optimal performance. In this guide, we’ll take a closer look at how to monitor fast-growing databases and tables in MySQL using a SQL script specifically designed for managing Disk I/O.

This query lists databases and tables, sorted by their size in descending order. It also includes separate data for the size of the actual data and the size of the indexes, which can be useful for identifying whether it’s the data or the indexes causing the size increase. Additionally, it provides a column with the total disk I/O wait time for each table.

Understanding which tables are growing rapidly and causing disk I/O can help identify performance issues. For example, a rapidly growing table could lead to longer backup times, slow query performance, and increased disk I/O. Also, if the growth is due to a large amount of data being written to the table, this could impact write-heavy operations and lead to increased disk I/O. By identifying these tables, we can then look into optimizing the queries involving these tables, archiving old data, or considering hardware upgrades.


In conclusion, managing Disk I/O in fast-growing MySQL databases need not be a daunting task. The SQL script we’ve walked through in this guide is a potent tool for identifying high growth areas and taking appropriate action. By regularly monitoring and taking necessary steps, you can ensure that your database’s performance remains at peak levels, even amidst rapid growth. Stay ahead of the curve by implementing these practices and maintaining an efficient and high-performing MySQL database environment.

About Shiv Iyer 456 Articles
Open Source Database Systems Engineer with a deep understanding of Optimizer Internals, Performance Engineering, Scalability and Data SRE. Shiv currently is the Founder, Investor, Board Member and CEO of multiple Database Systems Infrastructure Operations companies in the Transaction Processing Computing and ColumnStores ecosystem. He is also a frequent speaker in open source software conferences globally.