A poorly designed database can make your life hell as a dev while optimizing an app. On the other hand, A good design can speedup your development process along with the performance of the app.
Sometimes we want a summery of size consumed by our databases in MySQL engine.
This will list all databases that current MySQL user can access and list their size in megabyte.
Some of you may still surprise, why the callback function for WP_Ajax returning an additional 0 or something else which is very unwanted at the end of your own response.
Actually using Ajax directly into your plugin or theme is a little immature way. Cause you'll have to keep track of your files to make it work, which sometime become difficult. That's where WP_Ajax make things comfortable.