The answer is to modify the partition key to include a random suffix, which distributes writes evenly across partitions. This solves the DynamoDB hot partition problem by ensuring that no single partition absorbs all the write traffic from high-volume IoT sensors, as a random suffix on the partition key spreads each sensor’s records across multiple partitions rather than concentrating them on one. On the AWS Certified Database Specialty DBS-C01 exam, this scenario tests your understanding of DynamoDB’s per-partition throughput limits—even with auto scaling or on-demand, a single partition can only handle 1,000 WCU, so a hot key will throttle writes regardless of total table capacity. A common trap is to increase WCU or switch to on-demand, but neither fixes the underlying uneven distribution. Remember the memory tip: “Random suffix, no suffix” to recall that adding entropy to the partition key is the only way to avoid hot spots for high-frequency IoT data.
DBS-C01 Management and Operations Practice Question
This DBS-C01 practice question tests your understanding of management and operations. Read the scenario carefully and evaluate each option against the stated constraints before committing to an answer. 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 company uses Amazon DynamoDB to store IoT sensor data. Each sensor writes a record every second. The table has a partition key of 'sensor_id' and a sort key of 'timestamp'. Over time, the team notices that write performance degrades for certain sensors that generate more data. The table uses provisioned capacity with auto scaling enabled. The application uses eventual consistency. The team needs to ensure consistent write performance without throttling. Which action should be taken?
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Modify the partition key to include a random number or prefix to distribute writes evenly.
Option C is correct because adding a random suffix to the partition key distributes writes across partitions, avoiding hot partitions. Option A is wrong because increasing WCU does not solve the partition hot spot, as the limit per partition is fixed. Option B is wrong because switching to on-demand still has per-partition limits. Option D is wrong because a GSI does not change the base table's write distribution.
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 partition key to include a random number or prefix to distribute writes evenly.
Why this is correct
Write sharding evens out the load across partitions, preventing any single partition from being overloaded.
Related concept
Read the scenario before looking for a memorised answer.
✗
Increase the provisioned write capacity units (WCU) to a higher value.
Why it's wrong here
A single partition can only handle up to 1,000 WCU; increasing WCU does not bypass this limit.
✗
Switch the table to on-demand capacity mode.
Why it's wrong here
On-demand still has a per-partition throughput limit; hot partitions can still throttle.
✗
Create a global secondary index (GSI) with a different partition key to handle writes.
Why it's wrong here
GSI is for read access patterns; it does not affect the write distribution of the base table.
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 DBS-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.
Management and Operations — This question tests Management and Operations — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Modify the partition key to include a random number or prefix to distribute writes evenly. — Option C is correct because adding a random suffix to the partition key distributes writes across partitions, avoiding hot partitions. Option A is wrong because increasing WCU does not solve the partition hot spot, as the limit per partition is fixed. Option B is wrong because switching to on-demand still has per-partition limits. Option D is wrong because a GSI does not change the base table's write distribution.
What should I do if I get this DBS-C01 question wrong?
Identify which DBS-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.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
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 →
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.
This DBS-C01 practice question is part of Courseiva's free Amazon Web Services 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 DBS-C01 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.