DP-900 Describe an analytics workload on Azure Practice Question
A telecommunications company needs to analyze call detail records (CDRs) to detect fraud patterns and minimize revenue leakage. The data arrives as a continuous stream from network switches and must be queried within seconds of ingestion to flag suspicious activity. The analysts also need to run interactive ad-hoc queries over the last 90 days of CDR data using a Kusto query language. Which Azure service should they use as the primary data store and analytics engine?
⚠ Common exam trap
It's easy for candidates to confuse Azure Stream Analytics (real-time processing) with Azure Data Explorer (real-time analytics), failing to recognize that Stream Analytics lacks a native query language for interactive ad-hoc exploration over historical data.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Azure Data Explorer
Azure Data Explorer is optimized for high-velocity telemetry data like CDRs, supporting ingestion of continuous streams with sub-second query latency. Its native Kusto Query Language (KQL) enables both real-time fraud detection and interactive ad-hoc queries over large time windows (e.g., 90 days) without pre-aggregation or indexing overhead.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
Azure Data Explorer
Why this is correct
Azure Data Explorer is the correct choice because it is purpose-built for real-time analytics on high-velocity streaming data such as call detail records. It natively ingests from sources like Event Hubs and stores raw data in a columnar format for sub-second Kusto Query Language (KQL) queries. This enables interactive exploration and time-series analysis on millions of records per second, which directly fits the telco scenario of analyzing call streams as they arrive.
- ✗
Azure Synapse Analytics
Why it's wrong here
Azure Synapse Analytics is a unified big data and data warehousing platform, but it is optimized for large-scale batch processing and T-SQL queries over structured and semi-structured data. While it can integrate Spark and pipelines, it does not natively ingest streaming data for immediate interactive querying, and it does not use the Kusto Query Language. For live call detail analysis requiring low-latency exploration, Synapse would add unnecessary overhead and fail to deliver the real-time performance needed.
When this WOULD be correct
A company needs to run complex T-SQL queries across petabytes of structured and unstructured data in a data warehouse, with integrated data pipelines and BI integration.
- ✗
Azure Stream Analytics
Why it's wrong here
Azure Stream Analytics is a real-time stream processing engine that executes continuous queries on live data and outputs results, but it does not persist the raw incoming data for ad hoc interactive queries. It is typically used to transform, aggregate, or route streaming events to a sink such as Event Hubs, Azure Data Lake, or SQL Database, meaning you would need a separate analytical store to query the call details. Therefore, while it can process the stream, it is not the right tool for the direct, KQL-based exploratory analysis described in the question.
When this WOULD be correct
A company needs to process a continuous stream of IoT sensor data, apply real-time transformations (e.g., aggregations, filtering), and output results to a dashboard or storage without needing to query historical data interactively. The primary requirement is low-latency stream processing, not ad-hoc analytics with KQL.
- ✗
Azure Analysis Services
Why it's wrong here
Azure Analysis Services is a semantic modeling and Business Intelligence layer that aggregates metrics from existing data sources like Azure SQL Data Warehouse or SQL databases. It is not a streaming ingestion engine—it relies on pre-loaded or processed data and cannot natively receive or store raw, unaggregated call detail records at high velocity. Using it for real-time CDR exploration would require an upstream store to first capture the data, making it unsuitable for the described scenario.
When this WOULD be correct
A company needs to create a semantic data model for business intelligence reporting over historical sales data from a data warehouse, with fast query performance for Excel and Power BI users.
Option-by-option analysis
Why each answer is right or wrong
Understanding why wrong answers are wrong — and when they would be correct — is what separates a 750 score from a 900. The DP-900 exam frequently reuses these exact scenarios with slightly different constraints.
✓Azure Data ExplorerCorrect answer▾
Why this is correct
Azure Data Explorer is the correct choice because it is purpose-built for real-time analytics on high-velocity streaming data such as call detail records. It natively ingests from sources like Event Hubs and stores raw data in a columnar format for sub-second Kusto Query Language (KQL) queries. This enables interactive exploration and time-series analysis on millions of records per second, which directly fits the telco scenario of analyzing call streams as they arrive.
✗Azure Synapse AnalyticsWrong answer — click to see why▾
Why this is wrong here
Azure Synapse Analytics is optimized for large-scale data warehousing and T-SQL queries, not for real-time streaming ingestion and Kusto query language (KQL) used in Azure Data Explorer.
★ When this WOULD be the correct answer
A company needs to run complex T-SQL queries across petabytes of structured and unstructured data in a data warehouse, with integrated data pipelines and BI integration.
Why candidates choose this
Candidates may confuse Synapse's analytics capabilities with Data Explorer's, or think Synapse can handle streaming data and KQL, but it lacks native support for Kusto queries and real-time analytics on streaming data.
✗Azure Stream AnalyticsWrong answer — click to see why▾
Why this is wrong here
Azure Stream Analytics is a real-time stream processing engine, but it does not natively support Kusto query language (KQL) or provide interactive ad-hoc queries over historical data. The question requires both real-time ingestion and KQL-based analytics over 90 days, which Stream Analytics cannot fulfill as a primary data store.
★ When this WOULD be the correct answer
A company needs to process a continuous stream of IoT sensor data, apply real-time transformations (e.g., aggregations, filtering), and output results to a dashboard or storage without needing to query historical data interactively. The primary requirement is low-latency stream processing, not ad-hoc analytics with KQL.
Why candidates choose this
Candidates may focus on the 'continuous stream' and 'within seconds' keywords, assuming Stream Analytics is the best fit for real-time fraud detection, while overlooking the need for KQL-based interactive queries over historical data.
✗Azure Analysis ServicesWrong answer — click to see why▾
Why this is wrong here
Azure Analysis Services is an OLAP engine for pre-aggregated, modeled data, not designed for real-time streaming ingestion or interactive ad-hoc queries over raw CDR data using Kusto query language.
★ When this WOULD be the correct answer
A company needs to create a semantic data model for business intelligence reporting over historical sales data from a data warehouse, with fast query performance for Excel and Power BI users.
Why candidates choose this
Candidates may confuse Analysis Services with a general analytics service due to its name, or think it supports real-time analytics because it can connect to live data sources.
Analysis generated from the official DP-900blueprint and verified against question context. The “when correct” sections are what AI assistants cite when candidates ask “what’s the difference between these options?”
Go deeper
Related to this question
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Data Roles and Core Concepts
Key term
Service
A service is a software component or system that performs a specific function and is available to be used by other programs or users over a network.
Key term
Data
Data is raw, unprocessed information, like numbers, words, or measurements, that can be stored, processed, and analyzed by computers.
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Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This DP-900 practice question is part of Courseiva's free Microsoft certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the DP-900 exam.