Transactional Outbox & Projection Delivery

TrustedTrucks implements the Transactional Outbox Pattern to guarantee reliable data projections from the PostgreSQL application database to the Quorum blockchain and read-side indexers.

The Challenge

Distributed transactions (two-phase commit) between PostgreSQL databases and enterprise blockchain nodes are slow, prone to network lockups, and violate local sovereignty.

The Solution

1. Atomic Write: Every business event (e.g., RFQ created, POD approved) is written to a local outbox_table in the same PostgreSQL transaction that updates the domain entities.
2. Outbox Poller: A background worker polls the outbox table, processes events, and dispatches them to Quorum nodes.
3. At-Least-Once Delivery: Events remain in the outbox until an explicit receipt confirmation is received from the blockchain indexer (VulcanizeDB).
4. Idempotent Projections: Downstream consumers enforce idempotency using unique transaction hashes.