Another new feature in WordPress blog publishing system added since WordPress version 2.6 is post revisions tracking similar to version control system, which provides Wiki-like style tracking of edits been made onto the posts or pages. Post revisions tracking allows bloggers and authors to view who, on when, made what changes to any post or page, with ability to compare for differences between each saved versions, or revert back to older version.
Each version of post revisions is stored in WordPress database in wp_posts table. Over time, the database may grows bigger and becomes bloated especially when user prefer to click on “Save” button while writing a post or page (contrary to popular belief, auto-save feature in WordPress does not actually trigger or create a new revision version, unless specifically configure). Increasing size of database will surely putting more strains to busy web server, and may slow down post retrieval and web page serving. Beside, WordPress database backups will take longer time and bigger bandwidth to be downloaded.
For WordPress 2.6 or newer version users who feel that post revisions feature is not useful and suffice with AutoSave feature built-in in WordPress editor, post revisions tracking and keeping feature can be disabled and turned off.
WordPress provides constant WP_POST_REVISIONS that can be used in wp-config.php configuration file or plugin to set the status state for post revisions feature. To turn off and disable automatic post revisions all versions saving feature in WordPress 2.6 or later version, simply add the following line of code to wp-config.php file located in the root or home directory of WordPress blog.
Once set, WordPress does not attempt to save or store any revisions, except the one AutoSave per post.