How to Disable Post Revision in Wordpress

Everyone know about WordPress is use for blog website creation and it's provide all features and functionality for create any type of blog.
WordPress provide `Revision` functionality also for save post revision it is like previews post operation. this functionality use when you change some changes of any post today and after that you want to receive previous post than its save as revision and you directly save post as previous post.
Revision is like undo command in our computer.

But sometimes when you confirm that your changes of any post and page are complete and you cant change anything in that than revision is not useful. therefore its must to remove that functionality because revision functionality increase database size.So it's necessary to remove that functionality to optimize database size.
Here simple way to stop post revision from post

1. Open WP-config.php file in WordPress root directory.
2. Enter define('WP_POST_REVISIONS', false );
3. Save and Upload file.

Now its stop your post revision and optimize your database size.