A logistics company drops CSV manifests into a storage bucket at unpredictable times during the day. Each new manifest should start a load into the analytics warehouse within seconds, without any idle polling. What should the engineer set up?
Show answer and explanation
Answer: B
Object creation events in Cloud Storage can drive an Eventarc trigger or a Cloud Function that starts the load as soon as a manifest lands, so latency is seconds and nothing polls. A workflow orchestrator such as Cloud Composer can sequence follow-up steps when the load needs more stages. Minute-level listing wastes calls and still lags, a person-driven process cannot meet the timing, and warehouse scheduled queries run SQL on a timer rather than observing storage.
Why the other options are wrong
- A. Polling the bucket every minute adds up to a minute of delay and repeated listing cost, and it runs even when no files arrived, which the requirement rules out.
- C. Waiting for a person to act on an email adds human delay, is not reliable at unpredictable times, and does not meet the seconds-level target.
- D. Scheduled queries execute SQL on a timer and cannot watch a storage bucket for new objects, so this option cannot detect a manifest when it arrives.