How to implement Event-carried State Transfer?

I watched Mr. Martin Fowler's seminar on Event-Drivent Architecture. I see the benefits of Event-carried State Transfer but still haven't found a way to do it as he said. How can I copy data from this database to the database continuously, and can this copy cause errors?

Copy directly from one database to another is usually a bad idea as it creates coupling. A better approach is for one service to publish events about the changes, events that other then can subscribe to.

The publishing of events can be implemented in many different ways. For example:

• The publisher can publish an ATOM feed that the subscribers can poll and traverse for changes. For example the EventStoreDB publishes ATOM feeds to support this.

• The publisher can publish its events to Kafka, that then subscribers can consume events from.