The answer is to 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. This is correct because the current design forces the first Lambda function to wait synchronously for the Elastic Transcoder job to finish, which causes a Lambda function timeout waiting for long running job—the 15-minute Lambda execution limit is exceeded even though the average transcoding job takes 10 minutes, as any delay pushes it over the cap. On the AWS Certified Data Engineer Associate DEA-C01 exam, this scenario tests your understanding of decoupling long-running processes from Lambda’s synchronous execution model, a common trap where candidates mistakenly increase timeouts or adjust concurrency instead of recognizing that Lambda is not designed to wait for external jobs. The key insight is that Lambda should trigger work and then hand off monitoring to an event-driven workflow. Memory tip: “Fire and forget—Lambda submits, SNS notifies, second Lambda finishes.”
DEA-C01 Data Ingestion and Transformation Practice Question
This DEA-C01 practice question tests your understanding of data ingestion and transformation. The scenario asks you to isolate a root cause — eliminate options that address a different problem before choosing. 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 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?
Increase the Lambda function's reserved concurrency to allow multiple invocations in parallel.
Why wrong: Concurrency does not fix timeout issues.
B
Increase the Lambda function timeout to 20 minutes to accommodate longer transcoding jobs.
Why wrong: This does not address the root cause of waiting for the job.
C
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.
Decoupling submission from completion avoids timeout.
D
Replace AWS Transfer Family with AWS Database Migration Service to handle file transfers more efficiently.
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.
Option B is correct because the Lambda function should not wait for the transcoding job to complete; it should submit the job and exit. The current design synchronously waits, causing timeouts. Option A is wrong because increasing the timeout to 20 minutes may still fail if jobs take longer. Option C is wrong because the issue is not about concurrency. Option D is wrong because DMS is for database migration, not file processing.
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.
✗
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.
Related concept
Read the scenario before looking for a memorised answer.
✗
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.
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 DEA-C01 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.
Data Ingestion and Transformation — This question tests Data Ingestion and Transformation — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: 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. — Option B is correct because the Lambda function should not wait for the transcoding job to complete; it should submit the job and exit. The current design synchronously waits, causing timeouts. Option A is wrong because increasing the timeout to 20 minutes may still fail if jobs take longer. Option C is wrong because the issue is not about concurrency. Option D is wrong because DMS is for database migration, not file processing.
What should I do if I get this DEA-C01 question wrong?
Identify which DEA-C01 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.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
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Question Discussion
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