Hands-On Microservices with Kubernetes

Employing Command Query Responsibility Segregation

With Command Query Responsibility Segregation (CQRS), the data from the various microservices is aggregated to a new read-only data store that is designed to answer specific queries. The meaning of the name is that you separate (segregate) the responsibility of updating data (commands) from the responsibility of reading data (queries). Different services are in charge of those activities. It is often implemented by watching for changes to all data stores and requires a change notification system in place. You could use polling too, but that's often undesirable. This solution shines when there are known queries that are used often.

Here is an illustration of CQRS in action. The CQRS service ...