Answer: Backlogged Input Events, Watermark Delay

When monitoring Azure Stream Analytics job performance to ensure adequate streaming unit (SU) provisioning, **Backlogged Input Events** and **Watermark Delay** are the two most critical metrics to monitor alongside SU % Utilization. ## Why Backlogged Input Events (A) is essential: - This metric indicates the number of input events that are waiting to be processed by the job - A consistently high backlog suggests the job cannot keep up with the incoming data rate - Growing backlog indicates insufficient processing capacity, requiring additional SUs - This directly correlates with whether the current SU allocation can handle the workload ## Why Watermark Delay (B) is essential: - Watermark delay measures how far behind real-time the job's processing is - High watermark delay indicates the job is falling behind in processing events - This metric shows temporal processing lag, which directly impacts job performance - Sustained high delay suggests the need for more SUs to catch up with real-time processing ## Why other options are less suitable: - **Function Events (C)**: While useful for monitoring Azure Functions integration, it doesn't directly indicate SU capacity needs - **Out of Order Events (D)**: This relates to event ordering and windowing logic, not capacity planning - **Late Input Events (E)**: This indicates events arriving outside their expected time windows, which is more about data quality than capacity requirements Monitoring Backlogged Input Events and Watermark Delay together with SU % Utilization provides a comprehensive view of whether the job has sufficient resources to handle the workload efficiently.

Author: LeetQuiz Editorial Team