Autosave and revisions in WordPress
WordPress by definition performs automatic saves of each post being currently edited and also, for each post update, it creates a revision. This enlarges database and sometimes can make life a little bit harder, because both WordPress and browser can get a little bit wako on any of these mechanisms. So, here is a quick way of disabling these features.
This post is based on Revision Management in Wrodpress Codex. Refer to it for details.