VietMX Staff asked 3 years ago
Microservices introduce eventual consistency issues because of their laudable insistence on decentralized data management. With a monolith, you can update a bunch of things together in a single transaction. Microservices require multiple resources to update, and distributed transactions are frowned upon (for good reason). So now, developers need to be aware of consistency issues, and figure out how to detect when things are out of sync before doing anything the code will regret.
Think how transactions occur and what kind make sense for your services then, you can implement a rollback mechanism that un-does the original operation, or a 2-phase commit system that reserves the original operation until told to commit for real.
Financial services do this kind of thing all the time – if I want to move money from my bank to your bank, there is no single transaction like you’d have in a DB. You don’t know what systems either bank is running, so must effectively treat each like your microservices. In this case, my bank would move my money from my account to a holding account and then tell your bank they have some money, if that send fails, my bank will refund my account with the money they tried to send.
