Outbox: durable intent, duplicate delivery

C1: rollback both | C2: resume relay | C3: resend same event ID

Outbox: durable intent, duplicate delivery C1: rollback both | C2: resume relay | C3: resend same event ID BEGIN: order + event E (C1 before commit) COMMIT both (C2 after commit) Read committed pending E Event E Send E Accepted (C3: crash before sent update) Normal: mark E sent C3 recovery instead: resend E (duplicate) Order API · Sequence participant Order API Orders + Outbox · Sequence participant Orders + Outbox Relay · Sequence participant Relay Queue · Sequence participant Queue Legend return default message