SAGA-PATTERN

Saga pattern is a distributed long-transaction pattern decomposed into locally compensable sub-transactions — an alternative to 2PC for orchestrating multi-system EDI flows.

Definition

Saga comes from the 1987 'Sagas' paper by Garcia-Molina and Salem. Each successful step publishes an event triggering the next; on failure, compensations roll back earlier steps. Two variants: orchestration (central coordinator) vs. choreography (event bus).

Origin

Original academic paper Princeton 1987. Reintroduced to the microservices world by Chris Richardson (Eventuate, microservices.io) from 2014. Widely adopted since 2018.

Use

An EDI order triggers: (1) reserve stock, (2) debit account, (3) emit invoice. If the debit fails, compensations: (-1) release stock. Each step is owned by a service; the Saga orchestrator (e.g. AWS Step Functions or Temporal) or Kafka choreography coordinates.

Related terms

• Choreography vs orchestration — variants.
• Event sourcing — shared foundation.
• Outbox pattern — publisher pattern.
• ACID vs BASE — consistency axis.