Question 1mediummultiple choice
Full question →mediummultiple choiceObjective-mapped
A real-time leaderboard for an online game needs to store player scores and quickly retrieve the top 100 players. The data must update frequently as players achieve new scores, and the application requires sub-millisecond read and write latency. Which Azure data store is best suited for this requirement?
Answer choices
Why each option matters
Good practice is not just finding the correct option. The wrong answers often show the exact trap the exam wants you to fall into.
A
Distractor review
Azure Cosmos DB Core (SQL) API
Cosmos DB can store and query data with low latency, but it is not optimized for real-time leaderboard sorted sets; it is a full-featured NoSQL database with higher latency (typically a few milliseconds) and cost compared to an in-memory cache.
B
Distractor review
Azure Table Storage
Azure Table Storage is a NoSQL key-value store that does not natively support sorted sets or rank-based queries, making it unsuitable for real-time leaderboard retrieval.
C
Best answer
Azure Cache for Redis
Azure Cache for Redis provides in-memory data structures including sorted sets, enabling high-performance leaderboard operations with sub-millisecond latency. It is purpose-built for such real-time scenarios.
D
Distractor review
Azure Blob Storage
Azure Blob Storage is designed for large-scale unstructured data such as files, images, and backups, and cannot provide the low-latency sorted set operations required for a real-time leaderboard.
Common exam trap
Common exam trap: NAT rules depend on direction and matching traffic
NAT is not only about the public address. The inside/outside interface roles and the ACL or rule that matches traffic are just as important.
Technical deep dive
How to think about this question
NAT questions usually test address translation, overload/PAT behaviour, static mappings and whether the right traffic is being translated. Read the interface direction and address terms carefully.
KKey Concepts to Remember
- Static NAT maps one inside address to one outside address.
- PAT allows many inside hosts to share one public address using ports.
- Inside local and inside global describe the private and translated addresses.
- NAT ACLs identify traffic for translation, not always security filtering.
TExam Day Tips
- Identify inside and outside interfaces first.
- Check whether the scenario needs static NAT, dynamic NAT or PAT.
- Do not confuse NAT matching ACLs with normal packet-filtering intent.
Related practice questions
Related DP-900 practice-question pages
Use these pages to review the topic behind this question. This is how one missed question becomes focused revision.
More questions from this exam
Keep practising from the same exam bank, or move into a focused topic page if this question exposed a weak area.
Question 1
A data engineer needs to process streaming data from IoT devices and store the results in Azure Data Lake Storage for long-term analytics. The data must be processed in near real-time to detect anomalies and trigger alerts. Which Azure service should the engineer use for stream processing?
Question 2
A data engineer needs to query data stored in CSV files in Azure Data Lake Storage Gen2 using T-SQL in Azure Synapse Analytics, without loading the data into the database. Which feature should they use?
Question 3
A data engineer needs to process raw clickstream data from multiple websites that is stored in Azure Blob Storage as JSON files. The processing must run automatically every hour, transform the data into a structured format for reporting, and handle schema changes in the source data without manual intervention. Which Azure service should be used?
Question 4
A data engineer is designing a data lake architecture in Azure. They plan to first ingest raw data from various sources into a landing zone in Azure Data Lake Storage Gen2. Then they will clean, validate, and deduplicate that data in a second zone. Finally, they will create aggregated, business-ready datasets in a third zone for analysts. This layered approach is known as which architecture?
Question 5
A data engineer needs to transform large datasets stored in Azure Data Lake Storage Gen2 using Python and Apache Spark. They want a serverless compute option that automatically scales and requires no cluster management. Which Azure service should they use?
Question 6
A company collects customer feedback forms. Each form contains always-present fields like CustomerID and SubmissionDate, but also a free-text Comments field and optional fields like Rating or ProductCategory that vary between forms. How should this data be classified?
FAQ
Questions learners often ask
What does this DP-900 question test?
Static NAT maps one inside address to one outside address.
What is the correct answer to this question?
The correct answer is: Azure Cache for Redis — Azure Cache for Redis is an in-memory data store that supports sorted sets (e.g., native ZADD and ZRANGE commands), making it ideal for leaderboard scenarios with sub-millisecond latency. Cosmos DB is also fast but typically operates at millisecond latencies and is more expensive for this simple sorted set workload. Table Storage and Blob Storage are not optimized for sorted ranking updates.
What should I do if I get this DP-900 question wrong?
Then try more questions from the same exam bank and focus on understanding why the wrong options are tempting.
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