Edit 25 July 2008
I’ve prepared three plugins that can disable Revisions, Autosave or both of them at the same time.
Access here: Disable Revisions and Autosave plugins

I’ve recently updated my blog to the last WordPress 2.6 version.
The new version is very bold and I want generally suggest everyone to upgrade to it.

But I’ve also got to say that all the new version goods are mined by a major new introduced feature, a big problem to me and some other users out there: I’m talking about the Revisions and the new AutoSave function.
Revisions simply save the posts many times: WP will add a new row in the DB every time an user change a post; this could be good when the blog is maintained by different editors, cos they can track the various versions/revisions of every post, but it’s actually totally resources wasting to all the single editors ones.
AutoSave now create a second copy of the post that is stored and used to keep the post up-to-date when a subsequent AutoSave is executed on the same one. This is quite annoying too. I never liked much the AutoSave and the new implementation is even worser to me.

I’ve started roaming around the net looking for a solution.
I’ve found a couple of workarounds that can completely solve the problem when used at the same time.

STEP 1 - by me

I’ve found that clearing all the cookies relative to your Wp’s domain installation is always a good start when you make an update.
This is good too on 2.6 especially if you’re going to use the new SSL ones.

STEP 2 - Stop the Revisions scheme - Lester Chan article

To turn off the revisions edit the wp-config file adding this following code after the DB settings lines.

define(‘WP_POST_REVISIONS’, false);

You can also delete all post revisions by running this query in phpMyAdmin:
Be sure to backup your database first before performing any queries in phpMyAdmin.

DELETE FROM wp_posts WHERE post_type = ‘revision’;

STEP 3 - Stop the AutoSave - Untwisted Vortex article

Lester reports that AutoSave doesn’t create a revision.
This is not completely true cos some users (I’m on the same boat) have reported that one revision is created by AutoSave too; it’s actually not clear if this is a behavior resulting from a WP’s bug/problem or a particular provider’s systems configuration.

The solution is to create a plugin that stops the AutoSave function.

<?php
/*
Plugin Name: Disable Autosave
*/
function disable_autosave() {
wp_deregister_script('autosave');
}
add_action( 'wp_print_scripts', 'disable_autosave' );
?>

Select the above reported code, copy it and paste it into a new blank text document.
Save it as “disable-autosave.php”, upload it to the WP’s plugins directory and then activate the plugin.

I’ve also prepared the plugin version here: disable-autosave.zip (Right Click, Save As)