Question 1,536 of 724
DVA-C02 Troubleshooting and Optimization Practice Question
A developer deployed a new version of a Lambda function that processes S3 events. After deployment, some S3 events are not being processed. The CloudWatch Logs show no errors. What is the most likely cause?
⚠ Common exam trap
Watch out — candidates often assume deploying a new Lambda version automatically updates all event sources, but S3 event notifications are static ARN references that must be manually updated or use aliases to reflect the new version.
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 S3 bucket's event notification still points to the old Lambda function.
After deploying a new version of a Lambda function, the S3 bucket's event notification configuration still references the Amazon Resource Name (ARN) of the old Lambda function version or the function without a qualifier. S3 event notifications are configured to invoke a specific Lambda function ARN, and if the ARN does not point to the new version (e.g., by using an alias or the $LATEST qualifier), events will continue to be sent to the old version, which may not be processing them. Since CloudWatch Logs show no errors, the old version is likely not being invoked or is not logging, confirming the mismatch.
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 has a syntax error.
Why it's wrong here
A syntax error in a Lambda function would prevent it from executing successfully, leading to "Function errors" or "Invocation errors" being logged in Amazon CloudWatch. Since the problem statement implies the new version isn't even being invoked, and there are no reported errors, a syntax error is unlikely to be the root cause. Such errors are typically evident immediately upon invocation attempts, which are not occurring here.
- ✓
The S3 bucket's event notification still points to the old Lambda function.
Why this is correct
When a new Lambda function version is deployed, S3 event notifications configured to invoke a specific Lambda function (by ARN) will continue to invoke the previously configured version or $LATEST if no specific version was specified. To direct S3 events to a new specific version, the S3 event notification configuration on the bucket must be explicitly updated with the new Lambda function version ARN. This is a common operational oversight when deploying new function versions.
- ✗
The Lambda function alias is not pointing to the new version.
Why it's wrong here
S3 event notifications directly invoke a Lambda function using its specific ARN, which can include a version number or $LATEST. S3 does not inherently resolve or follow Lambda aliases; it invokes the exact ARN configured in the event notification. Therefore, whether an alias points to the new version or not is irrelevant to S3's invocation mechanism, as S3 would need to be configured with the alias ARN itself to use it.
- ✗
The S3 events are being throttled by Lambda.
Why it's wrong here
Lambda throttling occurs when the function exceeds its configured concurrent execution limits, causing subsequent invocation requests to be rejected. If S3 events were being throttled, Lambda would log "Throttled" errors in CloudWatch, indicating that invocations were attempted but denied. The problem statement suggests the new function is not being invoked at all, rather than being invoked and subsequently throttled.
Quick reference
AWS S3 Storage Class Comparison
| Storage Class | Min Duration | Retrieval | Use Case |
|---|---|---|---|
| S3 Standard | None | Immediate | Frequently accessed data |
| S3 Standard-IA | 30 days | Immediate | Infrequent access, rapid retrieval |
| S3 One Zone-IA | 30 days | Immediate | Non-critical infrequent data |
| S3 Intelligent-Tiering | None | Immediate–hours | Unknown or changing access patterns |
| S3 Glacier Instant | 90 days | Milliseconds | Archive with instant retrieval |
| S3 Glacier Flexible | 90 days | Minutes–hours | Archive, flexible retrieval |
| S3 Glacier Deep Archive | 180 days | Hours | Long-term compliance archive |
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Last reviewed: Jun 24, 2026
This DVA-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 DVA-C02 exam.
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