Post revisions, a WordPress 2.6 new feature can be very usefull, but it also increase the size of your MySQL database. Sure, you can manually delete posts revisions, but that’s a very long and boring work. Another solution is what I’m going to teach you: Batch deleting post revisions.
First of it all, login to your phpmyadmin and select your WordPress database. Once done, click on the sql button to open the sql command window.
Paste the following sql command in the sql window:
DELETE FROM wp_posts WHERE post_type = "revision";
Work’s done. You saved a precious space on your database by deleting unnecessary post revisions.