Tracking a single order being placed is easy. However, multiply that number with the million orders being placed and canceled every hour; it could quickly become a challenge in the reactive microservices domain. The challenge is how you would perform a transaction across multiple services. Not only is it difficult to track such a transaction, it poses other challenges, such as persisting such a transaction that spans the database and message broker. The task of reversing such an operation in the likelihood of the transaction breaking somewhere in the middle due to a service failure could be even more daunting.
In such a scenario, we can utilize the event sourcing pattern. This is a strong candidate, especially since we are not looking for a two-phase commit, generally referred to as 2PC. Instead of storing a transaction, we persist all the state-changing events of our entities. In other words, we store all the events that change their states in the form of entities, such as...