DBS-C01 Monitoring and Troubleshooting Practice Question
A company is using Amazon DynamoDB for a gaming leaderboard application. Recently, users have experienced increased latency when updating scores. The DynamoDB table has on-demand capacity mode. The application performs UpdateItem calls with a condition expression. Which action is most likely to reduce the latency?
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
✓
Ensure that there are no throttled requests in the CloudWatch metrics and verify that the table is not experiencing hot partitions.
Increased latency in DynamoDB can be caused by hot partitions where many requests hit the same partition, leading to throttling even with on-demand capacity if the partition limits are exceeded. Checking CloudWatch metrics for throttled requests and partition metrics helps identify hot partitions. Option A is incorrect because adding a GSI does not improve UpdateItem performance; it only helps query performance. Option B is incorrect: on-demand mode already handles capacity, and increasing read capacity units does not affect write operations like UpdateItem. Option C is incorrect: disabling conditional writes would break the application's concurrency control and does not guarantee latency reduction; condition evaluation is a fast, internal operation.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Add a global secondary index (GSI) with the score as the sort key to improve update performance.
Why it's wrong here
GSIs do not improve UpdateItem performance; they are for querying.
- ✗
Switch the table to provisioned capacity and increase the read capacity units to handle peak load.
Why it's wrong here
On-demand is suitable for variable workloads; provisioned requires manual scaling.
- ✗
Disable conditional writes to reduce the overhead of condition expression evaluation.
Why it's wrong here
Conditional writes are necessary for score updates and have minimal overhead.
- ✓
Ensure that there are no throttled requests in the CloudWatch metrics and verify that the table is not experiencing hot partitions.
Why this is correct
On-demand mode automatically scales, but hot partitions can cause latency; checking metrics helps identify partition issues.
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Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
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.