At-least-once processing: worker may execute the same logical job multiple times; safe systems must tolerate replay.
Idempotency: applying same operation repeatedly produces the same logical end state.
Replication lag: time between primary commit and secondary-replica completion.
Presigned URL: URL containing temporary access authorization derived from a signature and expiry time.
State transition guard: DB update condition that only permits legal state changes (for example running -> completed only if current status is running).
Outbox-style durability: pattern where intent for asynchronous work is written durably in same transaction as primary state change.
Terminal failure: final non-retry job state reached after exhausting configured retry attempts.