DEA-C01 Data Ingestion and Transformation Practice Question
A media company ingests large video files from partners via AWS Transfer Family (SFTP) into an S3 bucket. Each file is typically 2-5 GB. Once uploaded, an AWS Lambda function is triggered to transcode the video using Amazon Elastic Transcoder. The Lambda function reads the file from S3, submits a transcoding job to Elastic Transcoder, and writes the output back to a different S3 bucket. Recently, the Lambda function has been failing intermittently with timeouts, and the company reports that some files are not being transcoded. The CloudWatch logs show that the Lambda function is timing out after 15 minutes. The average transcoding job takes about 10 minutes to complete. The data engineer needs to fix the issue without changing the architecture drastically. What should the data engineer do?
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
✓
Modify the Lambda function to submit the transcoding job asynchronously and exit, using an SNS topic to trigger a second Lambda function when the job completes.
The Lambda function is timing out because it waits synchronously for the Elastic Transcoder job to complete, which can exceed the 15-minute Lambda timeout. The correct fix is to decouple the transcoding submission from the waiting: modify the Lambda function to submit the job asynchronously and exit immediately, then use an SNS topic or CloudWatch Events to trigger a second Lambda function when the job completes. This avoids the timeout. Option A (increasing reserved concurrency) does not address the root cause; timeouts occur per invocation, not due to lack of concurrency. Option B (increasing timeout to 20 minutes) might work but is not ideal because jobs can vary and still exceed the new timeout; the better pattern is asynchronous processing. Option D (replacing Transfer Family with DMS) is incorrect because DMS is for database migration, not file transfer and transcoding.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Increase the Lambda function's reserved concurrency to allow multiple invocations in parallel.
Why it's wrong here
Concurrency does not fix timeout issues.
- ✗
Increase the Lambda function timeout to 20 minutes to accommodate longer transcoding jobs.
Why it's wrong here
This does not address the root cause of waiting for the job.
- ✓
Modify the Lambda function to submit the transcoding job asynchronously and exit, using an SNS topic to trigger a second Lambda function when the job completes.
Why this is correct
Decoupling submission from completion avoids timeout.
- ✗
Replace AWS Transfer Family with AWS Database Migration Service to handle file transfers more efficiently.
Why it's wrong here
DMS is not suitable for file transfer.
Visual reference
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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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.