A company ingests streaming data from thousands of devices into Azure Event Hubs. They need to transform and aggregate the data in real time before storing it in Azure Data Lake Storage Gen2. Which Azure service should they use between Event Hubs and ADLS Gen2?
Azure Stream Analytics is a fully managed stream-processing engine built precisely for real-time, high-throughput IoT telemetry. It reads directly from Event Hubs or IoT Hub and runs declarative SQL-like queries that support tumbling, hopping, sliding, and session windows for continuous in-memory aggregation. Because the service handles checkpointing, scaling, and fault tolerance automatically, it delivers consistent sub-second results without the operational burden of managing clusters or writing custom stateful code.
Why this answer
Azure Stream Analytics is purpose-built for real-time data processing and analytics, allowing you to define SQL-like queries to transform and aggregate streaming data from Event Hubs before outputting it directly to Azure Data Lake Storage Gen2. It provides exactly-once delivery semantics and low-latency processing, making it the ideal service for this ingestion-to-storage pipeline.
Exam trap
The trap here is that candidates often confuse Azure Stream Analytics with Azure Functions or Azure Databricks for real-time processing, but Stream Analytics is the only service that provides a fully managed, low-latency, SQL-based streaming pipeline without requiring custom code or cluster management.
How to eliminate wrong answers
Option A is wrong because Azure Functions is a serverless compute service for event-driven code execution, but it lacks native streaming aggregation capabilities and would require custom code to handle stateful operations like windowed aggregates, leading to increased complexity and potential data loss. Option B is wrong because Azure Databricks is a big data analytics platform that can process streaming data via Structured Streaming, but it is overkill for a simple transform-and-aggregate pipeline and introduces higher latency and operational overhead compared to a dedicated streaming service. Option D is wrong because Azure Data Factory is an ETL and orchestration service designed for batch data movement and transformation, not real-time streaming; it cannot process data as it arrives in Event Hubs with sub-second latency.