MySQL is a widely used relational database management system that allows you to store and manipulate data. Indexes are an important feature in MySQL that help to optimize the performance of your database. An index is a data structure that allows you to quickly search for data in a database table. In this blog, we will discuss MySQL invisible indexes and their practical examples.

Table of Contents

1. What is an Invisible Index?
2. Benefits of using Invisible Indexes
3. Creating an Invisible Index
4. Checking MySQL Invisible Indexes
5. How to Drop an Invisible Index
6. Conclusion

What is an Invisible Index?

An invisible index in MySQL is an index that is not visible to the database optimizer, but still exists in the database. This means that the optimizer will not use this index while executing queries, but the index can still be used by the database developer to speed up specific queries.

Invisible indexes were introduced in MySQL version 8.0.13, and they are created using the CREATE INDEX statement with the INVISIBLE keyword.

Benefits of using Invisible Indexes

Using invisible indexes in MySQL has several benefits, including:

• Improved performance: Invisible indexes can be used to improve the performance of specific queries without affecting the performance of other queries.
• Reduced maintenance: Since invisible indexes are not visible to the database optimizer, they are not considered during query optimization. This can reduce the maintenance required for the index.
• Better query control: Invisible indexes allow you to control which queries use specific indexes, giving you more control over the performance of your database.

Creating an Invisible Index

Creating an invisible index in MySQL is similar to creating a regular index. To create an invisible index, you simply add the INVISIBLE keyword to the CREATE INDEX statement. Here's an example:

CREATE INDEX idx_lastname ON employees (last_name) INVISIBLE;

In this example, we create an invisible index named idx_lastname on the last_name column of the employees table.

Checking Invisible Indexes in MySQL

To check if an index is invisible in MySQL, you can use the SHOW INDEX statement. Here's an example:

SHOW INDEX FROM employees WHERE Key_name = 'idx_lastname'

This statement will display information about the idx_lastname index, including whether it is visible or invisible.

How to Drop an Invisible Index

Dropping an invisible index in MySQL is similar to dropping a regular index. To drop an invisible index, you simply use the DROP INDEX statement with the index name. Here's an example:

DROP INDEX idx_lastname ON employees;

This statement will drop the idx_lastname index from the employees table.

Conclusion

Invisible indexes in MySQL are a powerful tool that can be used to improve the performance of specific queries without affecting the performance of other queries. By using invisible indexes, you can reduce maintenance, improve query control, and optimize the performance of your database. With the examples provided in this blog, you can now create, check, and drop MySQL invisible indexes your database.