- A
The Lambda function is writing logs to CloudWatch Logs at a rate that exceeds the CloudWatch throttling limit.
Why wrong: CloudWatch throttling would not cause Lambda to throttle; Lambda throttling is at the invocation level.
- B
The S3 bucket is receiving more uploads than before, causing more Lambda invocations.
Why wrong: While increased invocations could cause throttling, the question states the code update is the only change.
- C
The updated Lambda function no longer has the required IAM permissions to access S3, causing retries that throttle.
Why wrong: Permission errors would result in 403 or 500 errors, not throttling (429).
- D
The code update increased the execution time of the Lambda function, leading to a higher number of concurrent executions that exceed the account-level concurrency limit.
Longer execution time means more invocations overlap, increasing concurrency and potentially hitting account limits.
Quick Answer
The answer is that the code update increased the Lambda function’s execution time, causing more concurrent executions to accumulate and exceed the account-level concurrency limit. When a function runs longer, each invocation occupies its execution slot for a greater duration, so under sustained invocation rates from S3 events, the number of active executions can surpass the default account concurrency of 1,000, triggering HTTP 429 throttling errors. This scenario tests your understanding of Lambda concurrency models on the SAP-C02 exam, where a common trap is to blame reserved concurrency or IAM permissions—but reserved concurrency only caps the function’s own usage, not the account-wide limit. The key insight is that a code change that lengthens runtime can indirectly cause throttling even if invocation volume stays the same. Memory tip: think “longer runtime = more overlap = concurrency pile-up,” and always check account-level limits before blaming reserved concurrency.
SAP-C02 Continuous Improvement for Existing Solutions Practice Question
This SAP-C02 practice question tests your understanding of continuous improvement for existing solutions. 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 has an AWS Lambda function that processes files uploaded to an S3 bucket. The Lambda function has been running successfully for months. Recently, the company updated the Lambda function code and started seeing occasional throttling errors (HTTP 429) from the Lambda service. The function's reserved concurrency is set to 100. The company is unsure why throttling is occurring only after the code update. 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 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
The code update increased the execution time of the Lambda function, leading to a higher number of concurrent executions that exceed the account-level concurrency limit.
Option B is correct because if the function invocation rate exceeds the account-level concurrency limit (default 1000), throttling occurs. The code update may have increased execution time, causing more concurrent invocations to pile up. Option A is wrong because increasing S3 events would increase invocations, but the reserved concurrency of 100 might still be within account limits. Option C is wrong because Lambda execution role permissions don't cause throttling errors. Option D is wrong because CloudWatch Logs throttling would cause logs to be dropped, not Lambda 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.
- ✗
The Lambda function is writing logs to CloudWatch Logs at a rate that exceeds the CloudWatch throttling limit.
Why it's wrong here
CloudWatch throttling would not cause Lambda to throttle; Lambda throttling is at the invocation level.
- ✗
The S3 bucket is receiving more uploads than before, causing more Lambda invocations.
Why it's wrong here
While increased invocations could cause throttling, the question states the code update is the only change.
- ✗
The updated Lambda function no longer has the required IAM permissions to access S3, causing retries that throttle.
Why it's wrong here
Permission errors would result in 403 or 500 errors, not throttling (429).
- ✓
The code update increased the execution time of the Lambda function, leading to a higher number of concurrent executions that exceed the account-level concurrency limit.
Why this is correct
Longer execution time means more invocations overlap, increasing concurrency and potentially hitting account limits.
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 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 SAP-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.
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Continuous Improvement for Existing Solutions — study guide chapter
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Continuous Improvement for Existing Solutions practice questions
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FAQ
Questions learners often ask
What does this SAP-C02 question test?
Continuous Improvement for Existing Solutions — This question tests Continuous Improvement for Existing Solutions — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: The code update increased the execution time of the Lambda function, leading to a higher number of concurrent executions that exceed the account-level concurrency limit. — Option B is correct because if the function invocation rate exceeds the account-level concurrency limit (default 1000), throttling occurs. The code update may have increased execution time, causing more concurrent invocations to pile up. Option A is wrong because increasing S3 events would increase invocations, but the reserved concurrency of 100 might still be within account limits. Option C is wrong because Lambda execution role permissions don't cause throttling errors. Option D is wrong because CloudWatch Logs throttling would cause logs to be dropped, not Lambda throttling.
What should I do if I get this SAP-C02 question wrong?
Identify which SAP-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.
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Last reviewed: Jun 20, 2026
This SAP-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 SAP-C02 exam.
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