CantonBolo

Optimize your database, support WordPress mutisite.
优化你的数据库，支持多站点。

Database Optimizer by Bolo

Optimize your database, support WordPress mutisite. 优化你的数据库，支持多站点。

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.

Database Optimizer by Bolo vs WUCO – WP Ultimate Cleanup & Optimization