Microservices should be designed in such a way that a single service is usually the only thing that reads or writes to a particular data store. In this model, services have full ownership over the domain models involved in the business capability they provide. Having clean boundaries makes it easier to think about the life cycle of data in a system. Some models in our system will change frequently, but many will be read much more often than they are written. In these cases, we can use a cache to store infrequently changed data, saving us from having to make a request to the database every time the object is requested. Database queries are typically more expensive than cache lookups, so it's ideal to use a cache whenever possible.
In addition to help improve performance, having an effective caching layer can help improve the reliability...
