Power BI Interview 2025: Real-Time Analytics & Streaming Data — Kafka, Event Hubs, IoT 🚀

Описание: Q1: How does Power BI support real-time dashboards and what are the main approaches?
Power BI enables real-time analytics through:

Push datasets (data pushed via REST API)

Streaming datasets (live streams, no history)

DirectQuery on real-time sources (like Azure SQL, Kafka connectors)
Example: A stock price dashboard updates every second via a push dataset.

Q2: How can you stream data into Power BI using Azure Event Hubs or IoT Hub?
Event Hubs or IoT Hub ingests high-volume events → stream processing (with Azure Stream Analytics) → output to Power BI dataset.
Example query in Azure Stream Analytics:

SELECT DeviceId, AVG(Temperature) AS AvgTemp, System.Timestamp AS EventTime
INTO PowerBI
FROM IoTInput TIMESTAMP BY EventEnqueuedTime
GROUP BY DeviceId, TumblingWindow(second, 10)


This streams 10-second average temperature readings to Power BI.

Q3: What role does Kafka play in integrating real-time data with Power BI?
Kafka handles distributed event streaming. Integration flow: Kafka → Kafka Connect → Azure Event Hubs or Spark Structured Streaming → Power BI push dataset.
Example: Retail transactions streaming into Kafka are aggregated by Spark and pushed to Power BI in near real-time.

Q4: How do you design a dataset for push streaming vs. DirectQuery for real-time use cases?

Push/Streaming dataset: Used for dashboards with live updates (e.g., call center queue). Data is pushed via REST API, not stored long-term.

DirectQuery: Used when querying real-time sources (like Azure SQL, Kusto/ADX). Supports historical + current data, but slower refresh than push.

Q5: What are the limitations and best practices of real-time streaming in Power BI?

Streaming datasets don’t support complex DAX or historical storage.

Push datasets can handle up to ~1M rows per hour, then overwrite.

Best practices: aggregate before pushing, limit visuals per dashboard, use hybrid approaches (DirectQuery + push).
Example: Use push dataset for a “Live KPI” tile while using DirectQuery for detailed drilldowns.

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