Google Cloud Professional Data Engineer — Question 192

You are building a streaming Dataflow pipeline that ingests noise level data from hundreds of sensors placed near construction sites across a city. The sensors measure noise level every ten seconds, and send that data to the pipeline when levels reach above 70 dBA. You need to detect the average noise level from a sensor when data is received for a duration of more than 30 minutes, but the window ends when no data has been received for 15 minutes. What should you do?

Answer options

• A. Use session windows with a 15-minute gap duration.
• B. Use session windows with a 30-minute gap duration.
• C. Use hopping windows with a 15-minute window, and a thirty-minute period.
• D. Use tumbling windows with a 15-minute window and a fifteen-minute .withAllowedLateness operator.

Correct answer: A

Explanation

The correct answer is A because session windows are designed to handle variable-length data streams and can close when there is a gap in data, fitting the requirement of ending the window after 15 minutes of inactivity. The other options either do not properly address the gap requirement or do not align with the need to detect data over a longer duration effectively.