Transactional Outbox Pattern
Transactional Outbox Pattern, Why? (part 1) Background In microservice and event driven architecture, transactional outbox pattern is crucial to maintain the state of data (or "aggregate" as per Domain Driven Design) in two or more persistent storages, especially when 2 Phase Commit is not available nor desired. You can read an excellent explanation of the pattern here . This article will be divided into two parts, part 1 will discuss why we need it, part 2 will discuss how we can implement it. In my experience designing solutions with transaction outbox pattern, I have come across multiple similar questions challenging why do we have to do it in such a complex way, and why can't we just reverse the order, use try catch clause, database transaction, etc. Based on those frequent conversations, here is my attempt to explain why we can't solve the problem with ordering, try catch clause or transactions. Suppose we have a system where we create a person record, which will