- A
Increase the Lambda timeout to allow more processing time.
Why wrong: Increasing the Lambda timeout does not reduce memory usage; it only allows the function to run longer, which does not address the out-of-memory issue.
- B
Increase the Lambda function memory to 3008 MB.
Why wrong: Increasing memory to 3008 MB might allow the function to handle larger files, but it does not fix the inefficiency of loading the entire file into memory. Streaming is a more effective optimization that avoids high memory usage.
- C
Use the AWS SDK's S3 GetObject with a stream and process in chunks.
Using the AWS SDK's S3 GetObject with a stream and processing in chunks prevents loading the entire CSV file into memory, directly solving the memory exhaustion problem for large files.
- D
Use S3 Select to retrieve only necessary columns.
Why wrong: S3 Select is used to retrieve only specific columns from S3 objects using SQL queries, which reduces data transfer but still requires the function to load the entire file into memory unless combined with streaming. It does not directly address the memory issue.
DVA-C02 Troubleshooting and Optimization Practice Question
This DVA-C02 practice question tests your understanding of troubleshooting and optimization. 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 developer is optimizing a Node.js Lambda function that processes CSV files from S3. The function reads the entire file into memory, processes it, and writes results to DynamoDB. For large files, the function runs out of memory. What is the MOST effective optimization?
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 the AWS SDK's S3 GetObject with a stream and process in chunks.
Option C is correct because using the AWS SDK's S3 GetObject with a stream allows the function to process the CSV file in chunks, avoiding loading the entire file into memory. This directly addresses the memory issue for large files. Option A is incorrect because increasing timeout does not reduce memory usage. Option B is incorrect because while increasing memory might help, it does not solve the root cause and may increase costs; streaming is more efficient. Option D is incorrect because S3 Select is used to filter columns from S3 objects using SQL, but it does not solve the problem of loading the entire file into memory; it could reduce the data transferred but the function still needs to handle streaming or chunking.
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 timeout to allow more processing time.
Why it's wrong here
Increasing the Lambda timeout does not reduce memory usage; it only allows the function to run longer, which does not address the out-of-memory issue.
- ✗
Increase the Lambda function memory to 3008 MB.
Why it's wrong here
Increasing memory to 3008 MB might allow the function to handle larger files, but it does not fix the inefficiency of loading the entire file into memory. Streaming is a more effective optimization that avoids high memory usage.
- ✓
Use the AWS SDK's S3 GetObject with a stream and process in chunks.
Why this is correct
Using the AWS SDK's S3 GetObject with a stream and processing in chunks prevents loading the entire CSV file into memory, directly solving the memory exhaustion problem for large files.
Related concept
Read the scenario before looking for a memorised answer.
- ✗
Use S3 Select to retrieve only necessary columns.
Why it's wrong here
S3 Select is used to retrieve only specific columns from S3 objects using SQL queries, which reduces data transfer but still requires the function to load the entire file into memory unless combined with streaming. It does not directly address the memory issue.
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.
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 |
What to study next
Got this wrong? Here's your next step.
Identify which DVA-C02 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.
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Troubleshooting and Optimization — study guide chapter
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FAQ
Questions learners often ask
What does this DVA-C02 question test?
Troubleshooting and Optimization — This question tests Troubleshooting and Optimization — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Use the AWS SDK's S3 GetObject with a stream and process in chunks. — Option C is correct because using the AWS SDK's S3 GetObject with a stream allows the function to process the CSV file in chunks, avoiding loading the entire file into memory. This directly addresses the memory issue for large files. Option A is incorrect because increasing timeout does not reduce memory usage. Option B is incorrect because while increasing memory might help, it does not solve the root cause and may increase costs; streaming is more efficient. Option D is incorrect because S3 Select is used to filter columns from S3 objects using SQL, but it does not solve the problem of loading the entire file into memory; it could reduce the data transferred but the function still needs to handle streaming or chunking.
What should I do if I get this DVA-C02 question wrong?
Identify which DVA-C02 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.
About these practice questions
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Last reviewed: Jun 20, 2026
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