Login to phpMyadmin.

Select database.
- Check all tables.
- Select "Optimize table".
Example as below:

You shall see the message "Your SQL query has been executed successfully" if done correctly.

Select database.
- Check all tables.
- Select "Optimize table".
Example as below:

You shall see the message "Your SQL query has been executed successfully" if done correctly.
Updated on: 14 / 08 / 2018