Overloads Action Scheduler with tens of thousands of order sync requests

Hello. A client re-connected this plugin yesterday, which re-ran the order sync. It needed to sync due to having been disconnected from a user account change. Today they found their Analytics data was out of date. I investigated and found tens of thousands of Action Scheduler actions scheduled at the same time (~24 hours ago) choking up other actions that other plugins and Woo itself need.

To fix this I initially cancelled all actions for MailChimp_WooCommerce_Single_Order to clear the overload of non Mailchimp actions. Then I wrote a quick action schedule myself to return those cancelled actions to pending status in batches of 10 per minute in order to keep it flowing in a kind fashion.

At 10 per minute this will take about a week to complete syncing of about 85k orders remaining in the queue. I’m keeping an eye on it to possibly turn up the batch size and get it done quicker.

I request that you figure out an optimal batch size and adjust your scheduler accordingly. Also, I believe it would be more efficient to sync batches of orders in one request rather than one action schedule per order.