- A
Stable key values that do not change
Stable keys avoid partition splits and data movement.
- B
Frequent updates to the key value
Why wrong: Updates to shard key can cause performance overhead and partition splits.
- C
High cardinality of the key
High cardinality ensures many distinct values for even distribution.
- D
Low cardinality of the key
Why wrong: Low cardinality leads to uneven distribution and hot partitions.
- E
Even distribution of request volume across partitions
Prevents hot partitions and throttling.
Question 617 of 851
DP-203 Shard key stability Practice Question
This DP-203 practice question tests your understanding of design and implement data storage. Match the stated requirement to the specific cloud service, access model, or configuration option — many options are valid in isolation but not for this scenario. A key principle to apply: shard key stability. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
Which THREE factors should you consider when choosing a shard key for Azure Cosmos DB to ensure even distribution and optimal performance?
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
✓
Stable key values that do not change
When choosing a shard key for Azure Cosmos DB, three key factors ensure even distribution and optimal performance. First, a stable key (Option A) is crucial because the shard key is immutable after document creation; changing it would require moving the document to a different partition, which Cosmos DB does not support, leading to cross-partition queries. Second, high cardinality (Option C) provides many distinct values, enabling the data to be spread evenly across physical partitions, preventing hot spots. Third, even distribution of request volume (Option E) ensures that the workload is balanced across partitions, avoiding throttling and maximizing throughput. Together, these factors maintain partition balance and efficient query routing.
Key principle: Shard key stability
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
Stable key values that do not change
Why this is correct
Stable keys avoid partition splits and data movement.
Related concept
Shard key stability
- ✗
Frequent updates to the key value
Why it's wrong here
Updates to shard key can cause performance overhead and partition splits.
- ✓
High cardinality of the key
Why this is correct
High cardinality ensures many distinct values for even distribution.
Related concept
Shard key stability
- ✗
Low cardinality of the key
Why it's wrong here
Low cardinality leads to uneven distribution and hot partitions.
- ✓
Even distribution of request volume across partitions
Why this is correct
Prevents hot partitions and throttling.
Related concept
Shard key stability
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates often confuse 'low cardinality' with 'high cardinality' or assume that frequently updated keys are acceptable because they think Cosmos DB can repartition dynamically, but in reality, the shard key is immutable after document creation.
Detailed technical explanation
How to think about this question
Under the hood, Cosmos DB uses a hash-based partitioning scheme where the shard key value is hashed to determine the physical partition (a logical partition within a physical partition). High cardinality ensures that the hash space is well-utilized, avoiding scenarios where a single logical partition exceeds the 20 GB storage limit or the 10,000 RU/s throughput cap per partition. In a real-world IoT scenario, using a device ID (high cardinality) as the shard key distributes writes evenly, whereas using a region code (low cardinality) would concentrate all writes from a popular region into one partition, causing throttling.
KKey Concepts to Remember
- Shard key stability
- High cardinality
- Even request distribution
- Partitioning in Cosmos DB
TExam Day Tips
- Watch for words such as best, first, most likely and least administrative effort.
- Review why wrong options are wrong, not only why the correct option is correct.
Key takeaway
Shard key stability
Real-world example
How this comes up in practice
A startup's cloud architect reviews their monthly bill and notices costs are higher than expected for a long-running batch job. Switching from on-demand instances to Reserved Instances — or using Spot/Preemptible VMs — can reduce compute costs by up to 72 %. Questions like this test whether you understand the tradeoffs between commitment, flexibility, and cost across cloud pricing models.
What to study next
Got this wrong? Here's your next step.
Review shard key stability, then practise related DP-203 questions on the same topic to reinforce the concept.
- →
Design and implement data storage — study guide chapter
Learn the concepts, then practise the questions
- →
Design and implement data storage practice questions
Targeted practice on this topic area only
- →
All DP-203 questions
851 questions across all exam domains
- →
Microsoft Azure Data Engineer Associate DP-203 study guide
Full concept coverage aligned to exam objectives
- →
DP-203 practice test guide
How to use practice tests most effectively before exam day
Related practice questions
Related DP-203 practice-question pages
Use these pages to review the topic behind this question. This is how one missed question becomes focused revision.
Secure, monitor, and optimize data storage and data processing practice questions
Practise DP-203 questions linked to Secure, monitor, and optimize data storage and data processing.
Design and develop data processing practice questions
Practise DP-203 questions linked to Design and develop data processing.
Design and implement data security practice questions
Practise DP-203 questions linked to Design and implement data security.
Monitor and optimize data storage and processing practice questions
Practise DP-203 questions linked to Monitor and optimize data storage and processing.
Design and implement data storage practice questions
Practise DP-203 questions linked to Design and implement data storage.
Develop data processing practice questions
Practise DP-203 questions linked to Develop data processing.
DP-203 fundamentals practice questions
Practise DP-203 questions linked to DP-203 fundamentals.
DP-203 scenario practice questions
Practise DP-203 questions linked to DP-203 scenario.
DP-203 troubleshooting practice questions
Practise DP-203 questions linked to DP-203 troubleshooting.
Practice this exam
Start a free DP-203 practice session
Short sessions build daily habit. Longer sessions build exam-day stamina. Try a timed session to simulate real conditions.
FAQ
Questions learners often ask
What does this DP-203 question test?
Design and implement data storage — This question tests Design and implement data storage — Shard key stability.
What is the correct answer to this question?
The correct answer is: Stable key values that do not change — When choosing a shard key for Azure Cosmos DB, three key factors ensure even distribution and optimal performance. First, a stable key (Option A) is crucial because the shard key is immutable after document creation; changing it would require moving the document to a different partition, which Cosmos DB does not support, leading to cross-partition queries. Second, high cardinality (Option C) provides many distinct values, enabling the data to be spread evenly across physical partitions, preventing hot spots. Third, even distribution of request volume (Option E) ensures that the workload is balanced across partitions, avoiding throttling and maximizing throughput. Together, these factors maintain partition balance and efficient query routing.
What should I do if I get this DP-203 question wrong?
Review shard key stability, then practise related DP-203 questions on the same topic to reinforce the concept.
What is the key concept behind this question?
Shard key stability
About these practice questions
Courseiva creates original exam-style practice questions with explanations and wrong-answer analysis. It does not publish real exam questions, exam dumps, or protected exam content. Learn why practice questions differ from exam dumps →
Keep practising
More DP-203 practice questions
- You are designing a data storage solution for IoT sensor data. The data is written thousands of times per second and req…
- A data processing job in Azure Synapse Analytics writes results to a table in the dedicated SQL pool. After a failure, t…
- A multinational corporation uses Azure Data Lake Storage Gen2 to store petabytes of parquet files partitioned by date an…
- A company ingests streaming data from IoT devices into Azure Event Hubs. The data must be processed in near real-time to…
- Which THREE factors should be considered when choosing between Azure Stream Analytics and Azure Databricks for a real-ti…
- You are designing a data lake on Azure Data Lake Storage Gen2. The data will be used by both batch processing (Spark) an…
Last reviewed: Jun 24, 2026
This DP-203 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-203 exam.
Question Discussion
Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.
Sign in to join the discussion.