Scheduled Post Guardian

On “shutdown” (after WP finishes a request), it checks a timer. If it has been 3 minutes since it last checked, it looks at all the scheduled posts, and runs them through a WordPress core function that either publishes them (if they should have gone out already), or re-schedules them, if their schedule has somehow gone away.

Normally, the plugin checks every 3 minutes. So it’s possible the post might go out a few minutes late. I hope this isn’t the end of the world. It’s a tradeoff between this and checking all the time. Additionally, if a check determines that there are currently no scheduled posts, it won’t look again for 15 minutes. Most people schedule posts more than 15 minutes in the future.

Yes. There are filters: scheduled_post_guardian_delay_minutes and scheduled_post_guardian_stretch_delay_minutes. Return a different number than 3 and 15 for those if you like.