When you move to microservices -- or rather, when you split your data across several DBs -- you sometimes end up basically reimplementing DB synchronization in

When you move to microservices -- or rather, when you split your data across several DBs -- you sometimes end up basically reimplementing DB synchronization in business logic layers that could (sometimes, and depending on scalability constraints) be solved by using DB transactions. So instead of a single DB transaction, often with a single SQL roundtrip, microservices can sometimes force through coordination of separate transactions to several DBs.