Question 590 of 1,616
Development with AWS ServiceshardMultiple ChoiceObjective-mapped

How to Use S3 Object Lambda for Large File Processing

This DVA-C02 practice question tests your understanding of development with aws services. Compare every option against the stated constraints before choosing — the best answer satisfies all requirements, not just the most obvious one. A key principle to apply: s3 Event Notification. 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 developer is designing a serverless application that processes large files uploaded to Amazon S3. Each file can be up to 5 GB. The processing involves extracting metadata and generating thumbnails. The developer wants to minimize processing time and cost. Which approach should the developer take?

Clue words in this question

Noticing these words before you look at the options changes how you read each choice.

  • Clue: "minimum / minimize"

    Why it matters: Asks for the least resource use — fewest addresses, smallest subnet, lowest overhead. Eliminate over-provisioned options even if they would technically work.

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

Use an S3 event notification to invoke a Lambda function that downloads the file, processes it, and uploads results.

Option D is correct because S3 event notifications can trigger a Lambda function immediately after an object is uploaded. The Lambda function can download the file from S3, extract metadata and generate thumbnails, then store the results. This approach is serverless and cost-effective, as you pay only for compute time. While Lambda has execution time and memory limits, processing a 5 GB file for metadata and thumbnails can be optimized to fit within these limits, making it the most appropriate choice among the options.

Key principle: S3 Event Notification

Answer analysis

Option-by-option breakdown

For each option: why learners choose it and why it is or isn't the right answer here.

  • Use S3 Object Lambda to process the object as it is being retrieved.

    Why it's wrong here

    Wrong. S3 Object Lambda processes objects on GET requests (retrieval), not upon upload. For post-upload processing, you need a trigger like S3 event notifications.

  • Use an S3 event notification to invoke a Lambda function that copies the object to an EC2 instance for processing.

    Why it's wrong here

    Wrong. Copying objects to an EC2 instance adds management overhead and cost, and EC2 instances run continuously even when idle, increasing expenses.

  • Use AWS Fargate to run a container that polls S3 for new objects and processes them.

    Why it's wrong here

    Wrong. AWS Fargate is more complex and costly for this simple processing task compared to Lambda. It requires container management and runs continuously even when there are no files to process.

  • Use an S3 event notification to invoke a Lambda function that downloads the file, processes it, and uploads results.

    Why this is correct

    Correct. S3 event notifications invoke a Lambda function directly when a new object is created. This allows processing the file in a serverless manner, minimizing cost and complexity. The Lambda function can efficiently handle the file by streaming and processing within its limits.

    Clue confirmation

    The clue word "minimum / minimize" in the question point toward this answer.

    Related concept

    S3 Event Notification

Common exam traps

Common exam trap: answer the scenario, not the keyword

Candidates often choose S3 Object Lambda for any processing, but it only acts on data retrieval. For upload-triggered processing, S3 event notification with Lambda is the standard serverless pattern.

Detailed technical explanation

How to think about this question

S3 Object Lambda works by intercepting GET requests and invoking a Lambda function that can transform the data on the fly using a streaming response. The function receives the original object from S3 via a pre-signed URL and can return modified data without storing it, which is ideal for metadata extraction and thumbnail generation because you can process chunks as they stream. Under the hood, S3 Object Lambda uses the `WriteGetObjectResponse` API to send transformed data back to the requester, enabling real-time processing without intermediate storage.

KKey Concepts to Remember

  • S3 Event Notification
  • AWS Lambda

TExam Day Tips

  • 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

S3 Event Notification

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.

Quick reference

AWS S3 Storage Class Comparison

Storage ClassMin DurationRetrievalUse Case
S3 StandardNoneImmediateFrequently accessed data
S3 Standard-IA30 daysImmediateInfrequent access, rapid retrieval
S3 One Zone-IA30 daysImmediateNon-critical infrequent data
S3 Intelligent-TieringNoneImmediate–hoursUnknown or changing access patterns
S3 Glacier Instant90 daysMillisecondsArchive with instant retrieval
S3 Glacier Flexible90 daysMinutes–hoursArchive, flexible retrieval
S3 Glacier Deep Archive180 daysHoursLong-term compliance archive

What to study next

Got this wrong? Here's your next step.

Review s3 Event Notification, then practise related DVA-C02 questions on the same topic to reinforce the concept.

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FAQ

Questions learners often ask

What does this DVA-C02 question test?

Development with AWS Services — This question tests Development with AWS Services — S3 Event Notification.

What is the correct answer to this question?

The correct answer is: Use an S3 event notification to invoke a Lambda function that downloads the file, processes it, and uploads results. — Option D is correct because S3 event notifications can trigger a Lambda function immediately after an object is uploaded. The Lambda function can download the file from S3, extract metadata and generate thumbnails, then store the results. This approach is serverless and cost-effective, as you pay only for compute time. While Lambda has execution time and memory limits, processing a 5 GB file for metadata and thumbnails can be optimized to fit within these limits, making it the most appropriate choice among the options.

What should I do if I get this DVA-C02 question wrong?

Review s3 Event Notification, then practise related DVA-C02 questions on the same topic to reinforce the concept.

Are there clue words in this question I should notice?

Yes — watch for: "minimum / minimize". Asks for the least resource use — fewest addresses, smallest subnet, lowest overhead. Eliminate over-provisioned options even if they would technically work.

What is the key concept behind this question?

S3 Event Notification

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Last reviewed: Jul 4, 2026

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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.