Event sourcing is easy!" they said. "Just record all of your user events" they said. "They're always useful." they said. So you did. You kept all the events. All of them. And now that you have them, there's just one question on your mind: How the heck do I manage all of it?!
The Dark Side of Event Sourcing: Managing Data Conversion
Talk by Marten Spoor, Michiel Overeem (1 hour)
Evolving software systems often includes data schema changes, and those cause the need for data conversion. This is no different in event sourced systems. Converting data between schemas while continuing the operation of the system is a challenge. In this talk, we will look at the possible conversion operations, the techniques to execute them, and strategies for deployment with zero-downtime. We will look at the possibilities and the trade-offs for designing and implementing upgrades for event sourced systems.