Duplicate Booking After Retry Troubleshooting

Duplicate bookings often appear when a second create is issued after the first attempt ended UNKNOWN. First determine which reservation represents the original intent and which one needs compensation.

Symptom

Two provider references for the same traveler/itinerary, duplicate confirmations, duplicate payment attempts, or multiple create attempts under one bookingIntentId.

Possible causes

Blind retry after timeout, regenerated idempotency keys, no provider idempotency, expired distributed locks, manual duplicate creation or client double-submit.

Diagnosis

Build a timeline of all attempts, compare bookingIntentId/idempotency keys, provider references and confirmation times, correlate payments, collect cancellation penalties and verify whether the traveler actually intended multiple bookings.

Recovery

Preserve the canonical booking, validate provider-specific cancellation rules for the duplicate, compensate duplicate payment where needed, and retain linked duplicate evidence for audit rather than deleting history.

Prevention

Use persistent idempotency, unique constraints, UNKNOWN retry blocking, client double-submit protection, operations warnings and provider/client-reference lookup.

Observability

Track duplicate provider references, blocked duplicate attempts, same-intent multi-create, duplicate payments and retry-induced cancellation cost.