Conflict Resolution

In Phase 1, both systems existed but only one wrote data: Magento. In Phase 2, both systems write data simultaneously. This is the most technically complex phase — and the one where most migrations introduce data corruption if they don’t have an explicit conflict resolution strategy. Answer-first: Phase 2 uses event-driven dual-write — not raw database dual-write. Microservices write to their PostgreSQL first, then publish a domain event to Dapr PubSub. The magento-sync-adapter service subscribes to those events and writes back to Magento. Conflicts (both systems update the same record concurrently) are resolved by a 5-policy matrix that differs by data type: timestamp-based for customer profiles, microservices-wins for order status and stock levels, and summation reconciliation for coupon usage counts. ...