If this alert raises notifications for 3 consecutive minutes and then stops, which statement must be true?

The data engineering team has configured a Databricks SQL query and alert to monitor the values in

a Delta Lake table. The recent_sensor_recordings table contains an identifying sensor_id alongside the timestamp and temperature for the most recent 5 minutes of recordings.

The below query is used to create the alert:

The query is set to refresh each minute and always completes in less than 10 seconds. The alert is set to trigger when mean (temperature) > 120. Notifications are triggered to be sent at most every 1 minute.

If this alert raises notifications for 3 consecutive minutes and then stops, which statement must be true?
A . The total average temperature across all sensors exceeded 120 on three consecutive executions of the query
B . The recent_sensor_recordingstable was unresponsive for three consecutive runs of the query
C . The source query failed to update properly for three consecutive minutes and then restarted
D . The maximum temperature recording for at least one sensor exceeded 120 on three consecutive executions of the query
E . The average temperature recordings for at least one sensor exceeded 120 on three consecutive executions of the query

View Answer

Answer: E

Explanation:

This is the correct answer because the query is using a GROUP BY clause on the sensor_id column, which means it will calculate the mean temperature for each sensor separately. The alert will trigger when the mean temperature for any sensor is greater than 120, which means at least one sensor had an average temperature above 120 for three consecutive minutes. The alert will stop when the mean temperature for all sensors drops below 120.

Verified Reference: [Databricks Certified Data Engineer Professional], under “SQL Analytics” section; Databricks Documentation, under “Alerts” section.