disable post revision

I hate wordpress’ post revision feature, its only function is to waste my database storage. Every time I save or modify a post, it’ll store a full copy of that post to my database. I don’t know why need to do that, that’s a personal blog, not a wiki. The funny thing is that I can’t find a option in admin dashboard to disable it, the writer of wordpress maybe think everybody need that feature, they are wrong!

Find a way to disable it, http://wordpress.org/support/topic/175886.

adding to wp-config:

define ('WP_POST_REVISIONS', 0);  // disable post revisions feature
define('AUTOSAVE_INTERVAL', 600); // auto save interval time

or install a plugin:
http://exper.3drecursions.com/2008/07/25/disable-revisions-and-autosave-plugin/

clean-up SQL:

# can't delete wp_postmeta and wp_term_relationships table
DELETE FROM wp-posts WHERE post_type='revision';
 
# delete all post revision data
DELETE a,b,c  
FROM wp_posts a  
LEFT JOIN wp_term_relationships b ON (a.ID = b.object_id)  
LEFT JOIN wp_postmeta c ON (a.ID = c.post_id)  
WHERE a.post_type = 'revision';