Google Cloud Professional Data Engineer — Question 70

Your company is streaming real-time sensor data from their factory floor into Bigtable and they have noticed extremely poor performance. How should the row key be redesigned to improve Bigtable performance on queries that populate real-time dashboards?

Answer options

• A. Use a row key of the form <timestamp>.
• B. Use a row key of the form <sensorid>.
• C. Use a row key of the form <timestamp>#<sensorid>.
• D. Use a row key of the form >#<sensorid>#<timestamp>.

Correct answer: D

Explanation

Option D is the correct answer because using a row key in the format >#<sensorid>#<timestamp> helps in distributing the data across the Bigtable nodes more evenly, which leads to improved query performance. Options A and B do not provide sufficient uniqueness or distribution, while option C, although better than A and B, still does not optimize for query performance as effectively as option D.