Multi Step Processes medium
You need to save a User to the database AND send a 'UserCreated' event to a message queue. If you do these as two separate steps in your code, one might succeed while the other fails. What pattern best solves this atomicity issue?
- A The Transactional Outbox Pattern
- B Two-Phase Commit (2PC)
- C Write-Behind Caching
- D Retry-After Header
Answer: A. The Transactional Outbox Pattern
The Outbox pattern saves the event to a database table ('Outbox') in the *same* transaction as the User insert. A separate process then reads the Outbox table and reliably publishes to the queue.
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