MySQL in-app is an App Service feature where MySQL database is created and MySQL server is running on the same instance side by side with the web server hosting the site. This is not recommended for the production environments.
Limitations on using MySQLinApp:
- Auto scale feature is not supported since MySQL currently runs on a single instance.
- Enabling Local cache is not supported.
- MySQL database cannot be accessed remotely. You can only access your database content using PHP Myadmin or using MySQL utilities in KUDU debug console.