Dual Write

Kind: anti-pattern

Layer: Enforcement Core

Record: architecture:dual-write

Severity: discouraged

Scope: event_messaging

Formed by: Write related state to two systems without atomicity, outbox, saga, reconciliation, or compensation.

Canonical: Ontology

A defect in which related state is written to two systems with no atomicity or compensation.

Listed in Architecture principles, after Lost Update and before Read-Your-Writes Violation.

Refactored by

• Outbox Pattern
• Saga Pattern
• Idempotent Consumer
• Reconciliation Job

Severity

• discouraged

Category

• Anti-patterns

Force

• Event messaging

Linked from

• Counting copies
• A system is a graph
• Definitions own what, code owns how
• Anti-patterns
• Event / Messaging / Asynchronous Architecture
• Transactions / State / Concurrency
• Severity levels
• The forces