> we have user profiles (user id > the users names, email etc) in one microservice, relationships between users (user id > other user ids) in another. > Each h

> we have user profiles (user id > the users names, email etc) in one microservice, relationships between users (user id > other user ids) in another. > Each has its own datastore How do you maintain referential integrity between datastores? For example, when a user is deleted, how do you update the relationships between users in a concurrency-safe way?