The answer is a low sampling rate, which causes the X-Ray SDK to drop many requests before they can be fully traced. When the sampling rate is set too low, the SDK may record only the root segment for a request while skipping the collection of downstream subsegments, resulting in incomplete traces that show no child segments. On the AWS Certified DevOps Engineer Professional DOP-C02 exam, this scenario tests your understanding of how X-Ray’s sampling configuration directly impacts trace completeness—a common trap is confusing sampling rate with segment size limits or missing annotations, which do not cause missing subsegments. Remember that the root segment is always created first, but if the sampling decision is made too late or the rate is too restrictive, subsegments are never emitted. Memory tip: think of sampling as a bouncer—if the bouncer is too strict (low rate), only the first person (root) gets in, and the rest (subsegments) are left outside.
DOP-C02 Monitoring and Logging Practice Question
This DOP-C02 practice question tests your understanding of monitoring and logging. 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. 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 is using AWS X-Ray to trace requests through a microservices application. Some traces are incomplete, showing only the root segment without any subsegments. The application uses the X-Ray SDK for Java. What is the most likely cause?
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue: "most likely"
Why it matters: Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
The sampling rate is set to a low value, causing many requests to be dropped.
Option A is correct because if the sampling rate is too low, many requests are not traced, resulting in incomplete traces. Option B is wrong because segment size limits do not cause missing subsegments. Option C is wrong because a missing annotation would not prevent subsegments from appearing. Option D is wrong because the SDK automatically sends traces to the X-Ray daemon.
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.
✗
The application is missing the x-amzn-trace-id header in incoming requests.
Why it's wrong here
Missing header would prevent tracing entirely, not just subsegments.
✗
The segment document size exceeds the maximum allowed size.
Why it's wrong here
Segment size limits cause errors, not missing subsegments.
✗
The X-Ray daemon is not running on the EC2 instances.
Why it's wrong here
The SDK sends traces directly to the X-Ray API, not through a daemon.
✓
The sampling rate is set to a low value, causing many requests to be dropped.
Why this is correct
Low sampling rate means fewer requests are traced, leading to incomplete traces.
Clue confirmation
The clue word "most likely" in the question point toward this answer.
Related concept
Read the scenario before looking for a memorised answer.
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 cloud solutions architect for a retail company is evaluating services for a new workload. The correct answer here reflects best practice for the specific scenario described — not a general cloud recommendation. Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option. Cloud exam questions reward reading the constraint carefully: the same technology can be right or wrong depending on the use case.
What to study next
Got this wrong? Here's your next step.
Identify which DOP-C02 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.
Monitoring and Logging — This question tests Monitoring and Logging — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: The sampling rate is set to a low value, causing many requests to be dropped. — Option A is correct because if the sampling rate is too low, many requests are not traced, resulting in incomplete traces. Option B is wrong because segment size limits do not cause missing subsegments. Option C is wrong because a missing annotation would not prevent subsegments from appearing. Option D is wrong because the SDK automatically sends traces to the X-Ray daemon.
What should I do if I get this DOP-C02 question wrong?
Identify which DOP-C02 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: "most likely". Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
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 →
These questions test the same concept from different angles. Work through them to make sure you can recognise it however the exam phrases it.
Variation 1. A company uses AWS X-Ray to trace requests through its microservices application. The DevOps engineer notices that some traces are incomplete. What is a possible reason?
easy
A.The X-Ray daemon is not running on the application servers.
B.X-Ray cannot trace requests that cross multiple AWS services.
✓ C.The X-Ray SDK sampling rate is configured too low, causing many requests to be skipped.
D.X-Ray requires the CloudWatch agent to be installed on all EC2 instances.
Why C: Option C is correct because the X-Ray SDK uses a sampling rate to decide which requests to record. If the sampling rate is set too low, a large percentage of requests are skipped, leading to incomplete traces. The DevOps engineer would observe missing segments for requests that were not sampled, even though the daemon and SDK are functioning correctly.
Last reviewed: Jun 20, 2026
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This DOP-C02 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 DOP-C02 exam.
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