DEA-C01 Data Ingestion and Transformation Practice Question
Network Topology
Refer to the exhibit. A data engineer has configured an S3 event notification to send an event to an SQS queue when objects are created in the 'incoming/' prefix. The engineer wants to trigger an AWS Lambda function to process the object. However, the Lambda function is not being invoked. What is the most likely cause?
⚠ Common exam trap
The DEA-C01 exam often tests the distinction between sending events to a queue (S3 → SQS) and actually consuming them (SQS → Lambda), so candidates mistakenly assume that simply having S3 send to SQS will automatically trigger Lambda without an explicit event source mapping.
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
✓
Lambda is not configured as an event source for the SQS queue.
The Lambda function is not being invoked because the SQS queue is not configured as an event source for Lambda. Even though S3 sends events to SQS, Lambda will only poll and process messages from the queue if an event source mapping (e.g., via CreateEventSourceMapping) is established. Without this mapping, the messages sit in the queue and Lambda remains idle.
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 lacks permission to read from the S3 bucket.
Why it's wrong here
Permission to S3 is not needed; Lambda needs SQS permission.
- ✓
Lambda is not configured as an event source for the SQS queue.
Why this is correct
Lambda must poll the SQS queue to be triggered.
- ✗
The SQS queue does not exist or is in a different account.
Why it's wrong here
The queue ARN is valid and exists.
- ✗
The S3 event notification filter prefix is incorrect.
Why it's wrong here
The prefix 'incoming/' is valid.
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 |
Go deeper
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JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This DEA-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 DEA-C01 exam.