> You still need cross-service transactions to publish the event only-once. Consider the case of "Publish the event to the queue. Fail to update / delete the entry in the event-buffer table."

I'm not sure this is the problem the author has set out to solve. Exactly once dispatching is really hard and requires much more than what's written about here. Even though the system the author wrote about is at-least-once, it guarantees an event isn't dispatched for data that's not stored or that data is stored for an event that's never dispatched.

I do think the author is incorrect in one place:

> While consumers should ideally be idempotent

They must be idempotent. For this very reason.