Marion Dorsett

The WordPress Database Table Optimizer plugin will automatically make sure that your WordPress MySQL database tables are always optimized.
I’ve also included an admin page located at Manage > Optimize Database. This page will allow you to confirm your WordPress MySQL database tables are optimized, show you the number of rows per table, and the size of the table.
<h3>Arbitrary section</h3>
This plugin uses Aidan Lister size_readable PHP function to show the file sizes of the MySQL tables. I’ve changed the name of the function to avoid naming conflicts with other plugins that may be using this function as well.
http://aidanlister.com/repos/v/function.size_readable.php
Special thanks to David Potter (http://dpotter.net/Technical/) for catching my oversight.
http://www.figmentthinking.com/wordpress-database-table-optimizer/#comment-74

Figment Thinking WordPress Database Table Optimizer

The WordPress Database Table Optimizer plugin will automatically make sure that your WordPress MySQL database…

pranacoder

WordPress stores a lot of excess information in your DB (like post revisions, auto drafts, spam and trashed comments, transient site options, etc.). 
Of course there’s a reason for that and some of this data is needed once in a while, but most of it is not critical. It just sits there taking up space and never being used. 
Over the time as your site grows the volume of this unused data grows with it making your database unreasonably huge thus effecting the site’s overall performance.
Using WUCO you can easily and safely clean up your database from those useless entries. With a single click you can remove revisions, drafts, auto drafts, orphaned post and comment meta, transient data and much more. You can also schedule the cleanups for later and they will be run automatically keeping your WordPress site clean and shiny.
And as all the best things in life WUCO is and always will be absolutely free.

WUCO – WP Ultimate Cleanup & Optimization

WUCO aka WP Ultimate Cleanup & Optimization, a free easy to use yet effective plugin designed to help you keep your MySQL database clean.

Figment Thinking WordPress Database Table Optimizer vs WUCO – WP Ultimate Cleanup & Optimization