Transactional Outbox

Prerequisite: Familiarity with the concepts introduced in Part 8 — Phase3 Full Cutover. Review it first if the terminology in this part is unfamiliar. Answer-first: Distributed transaction consistency is achieved using a choreography-based saga paired with a PostgreSQL transactional outbox. Business mutations write to the outbox atomically. Background workers publish events to Dapr PubSub every 500ms, while idempotent consumer handlers process compensation events on failure. When a customer places an order on the Composable Commerce Platform, seven events need to happen in sequence across four independent services: Order created → Payment authorized → Stock reserved → Fulfillment triggered → Notification sent → Loyalty points awarded → Shipping label generated. Any of these can fail. The network can fail. The database can fail. A third-party payment gateway can time out. ...

Banking Microservices in Go: Saga & Event Sourcing 1. Introduction: Deconstructing the Legacy Core Legacy banking platforms like Temenos T24 and Oracle FLEXCUBE were designed as rigid transactional monoliths for batch processing. Digital banking now requires decomposing these into event-driven microservices capable of real-time payments with sub-10ms latency. Migrating to a microservices architecture means dismantling these bottlenecks: Scaling limitations: Monoliths scale vertically (costly hardware), while microservices scale horizontally. Release cycles: Legacy cores require massive, risky quarterly releases. Microservices enable independent deployments. Data locking: Central databases in monoliths create severe lock contention during high-velocity events (like payday processing). By leveraging Go’s highly concurrent runtime and a distributed event-driven architecture, we optimize the system for <10ms database writes at 10,000 TPS, ensuring scalability and fault tolerance. ...