The correct solution is to modify the application to add a random suffix to the partition key when writing items, as this directly resolves DynamoDB hot partition write throttling by distributing the workload evenly across all partitions. When a single partition key like 'trip_id' receives too many concurrent writes, it exceeds that partition's throughput limit even if the table's total consumed WCU is below the provisioned 4,000—this is the classic hot partition symptom. On the AWS Certified Data Engineer Associate DEA-C01 exam, this scenario tests your understanding that throttling occurs at the partition level, not the table level, and that increasing WCU or using DAX (a read cache) won't fix write hotspots. A common trap is assuming more capacity solves everything, but the real issue is uneven key distribution. Memory tip: think "random prefix, even traffic"—spreading writes across partitions prevents any single partition from becoming a bottleneck.
DEA-C01 Data Store Management Practice Question
This DEA-C01 practice question tests your understanding of data store management. The scenario asks you to isolate a root cause — eliminate options that address a different problem before choosing. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. 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.
A startup is building a ride-sharing application that uses Amazon DynamoDB to store trip data. The table has a partition key of 'trip_id' and a sort key of 'status'. The application writes a new item when a trip starts and updates the status when the trip ends. The development team is experiencing high write latency during peak hours. The table is provisioned with 5,000 write capacity units (WCU) and 5,000 read capacity units (RCU). CloudWatch metrics show that WriteThrottleEvents are occurring frequently, but the consumed write capacity is never above 4,000 WCU. The team suspects that the issue is due to hot partitions. How should the data engineer resolve this issue?
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue: "never"
Why it matters: Absolute qualifier. True only if the statement has zero exceptions — be cautious of options that seem obvious but break down in edge cases.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Modify the application to add a random suffix to the partition key when writing items.
Option C is correct because using a random prefix for the partition key distributes writes across partitions, avoiding hot spots. Option A is incorrect because increasing WCU does not solve the hot partition issue; throttling happens at the partition level. Option B is incorrect because DAX is a cache for reads, not writes. Option D is incorrect because decreasing RCU is unrelated to write throttling.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
✓
Modify the application to add a random suffix to the partition key when writing items.
Why this is correct
Adding random suffix distributes writes across multiple partitions, reducing hot spots.
Clue confirmation
The clue word "never" in the question point toward this answer.
Related concept
Read the scenario before looking for a memorised answer.
✗
Enable DynamoDB Accelerator (DAX) to cache write operations.
Why it's wrong here
DAX caches reads, not writes.
✗
Decrease the provisioned RCU to 2,000 to reduce costs.
Why it's wrong here
Reducing RCU does not affect write throttling.
✗
Increase the provisioned WCU to 10,000 to handle the spikes.
Why it's wrong here
Increasing WCU does not alleviate hot partition issues; throttling occurs per partition.
Common exam traps
Common exam trap: answer the scenario, not the keyword
Many certification questions include familiar terms but test a specific constraint. Read the exact wording before choosing an answer that is generally true but wrong for this case.
Detailed technical explanation
How to think about this question
This question should be treated as a scenario, not a definition check. Identify the problem, the constraint and the best action. Then compare each option against those facts.
KKey Concepts to Remember
Read the scenario before looking for a memorised answer.
Find the constraint that changes the correct option.
Eliminate answers that are true in general but not in this case.
Use explanations to understand the rule behind the answer.
TExam Day Tips
→Underline the problem statement mentally.
→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
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
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.
Identify which DEA-C01 exam domain this question belongs to, then review the specific concept being tested. Practise related questions in that domain and focus on understanding why each wrong answer is tempting — not just why the correct answer is right.
Data Store Management — This question tests Data Store Management — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Modify the application to add a random suffix to the partition key when writing items. — Option C is correct because using a random prefix for the partition key distributes writes across partitions, avoiding hot spots. Option A is incorrect because increasing WCU does not solve the hot partition issue; throttling happens at the partition level. Option B is incorrect because DAX is a cache for reads, not writes. Option D is incorrect because decreasing RCU is unrelated to write throttling.
What should I do if I get this DEA-C01 question wrong?
Identify which DEA-C01 exam domain this question belongs to, then review the specific concept being tested. Practise related questions in that domain and focus on understanding why each wrong answer is tempting — not just why the correct answer is right.
Are there clue words in this question I should notice?
Yes — watch for: "never". Absolute qualifier. True only if the statement has zero exceptions — be cautious of options that seem obvious but break down in edge cases.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
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Question Discussion
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