You can speed up your db with The Database Cleanup feature.
Database may be full of garbage such as post revisions, trashed posts & pages, comments from trash & spam, trackbacks and pingbacks, transient options etc. These garbage causes the database to bloat and sql queries to slow down. In this case, you should clean up the database periodically.
The Database Cleanup feature reduces the database size significantly so that the db works quicker and CPU usage decreases.
Automatic Cleanup is a feature that can make your job a lot easier.
In order not to complicate this feature even more, we found it convenient to add only two options which are Once a Day and Once a Week. We recommend clearing once a week rather than every day.
In both cases, the first action takes place at 5 am the next day.
Note: The Automatic Cleanup feature works with WP Schedule which works when someone visits your WordPress site.