The dual-write bug you probably have in production (and the outbox pattern that fixes it)

Short summary

A common production bug: saving to a database and publishing to a message broker in sequence without a shared transaction, causing silent data drift or ghost events when either step fails. The fix is the transactional outbox pattern — store events in the same DB transaction as the state change, then a separate process publishes them. The article walks through a Go DDD implementation where domain aggregates record events, a simple outbox table persists them, and a relay process handles actual publishing.

• •Dual-write between DB and message broker causes silent data drift in ~0.1% of production calls
• •Transactional outbox stores events in the same DB transaction, eliminating the dual-write problem
• •Go DDD implementation: aggregates record domain events, repository saves them alongside state, relay process publishes asynchronously

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