The Lambda and Kappa Design Patterns for Persistent State
A while ago, I received a bunch of books on “big data” themes, one of which was about something called the Lambda Architecture. It presents a design-pattern useful for IT systems that have large amounts of persistent data representing “current state” - stored data like users, devices or bank-accounts which is mutable (updateable). I found it interesting but too complex for the issues I needed to deal with at the time.
Recently one of my work colleagues mentioned something called the Kappa Architecture which seemed to be related. I did some reading on that topic too, and found it to be a simplification of Lambda which is applicable to many more cases. Here are my notes on the topics for those interested.