The Outbox Pattern for Reliable Event Publishing
Learn how the transactional outbox pattern guarantees that database writes and Kafka events stay consistent, avoiding dual-write data loss.
The Dual-Write Problem
A service often needs to update its database and publish a Kafka event. Doing both as separate steps risks one succeeding and the other failing.
This dual-write problem leaves the database and Kafka inconsistent.
Why You Can't Just Try-Catch
If you commit the DB then publish, a crash in between loses the event.
If you publish then commit, a failed commit emits a phantom event. There is no atomic transaction spanning a relational DB and Kafka by default.
All lessons in this course
- Event Sourcing with Kafka
- Change Data Capture (CDC)
- Microservices Communication Patterns
- The Outbox Pattern for Reliable Event Publishing