Joshua Fredrickson

Use this plugin to automatically run the OPTIMIZE command on your WordPress database every day. There are no settings to configure. Simply activate the plugin and you’re set!
This plugin hooks into the existing WordPress cron system.

Optimize Database

Automatically optimize your database daily.

Automattic

Mohammad Jangda

Erick Hitter

Thorsten Ott

This plugin allows you to take control over the execution of cron jobs. It’s mainly useful for sites that either don’t get enough comments to ensure a frequent execution of wp-cron or for sites where the execution of cron via regular methods can cause race conditions resulting in multiple execution of wp-cron at the same time. It can also help when you run into posts that missed their schedule.
This plugin implements a secret parameter and ensures that cron jobs are only executed when this parameter is existing.
<h3>Limitations</h3>
This plugin performs a <code>remove_action( 'sanitize_comment_cookies', 'wp_cron' );</code> call in order to disable the spawning of new cron processes via the regular WordPress method. If <code>wp_cron</code> is hooked in an other action or called directly this might cause trouble.

WP-Cron Control

This plugin allows you to take control over the execution of cron jobs.

Optimize Database vs WP-Cron Control