Question 1hardmultiple choice
Full question →hardmultiple choiceObjective-mapped
A developer deployed an AWS Lambda function that is invoked by an Amazon SQS queue. The function is configured with a batch size of 10 and a timeout of 30 seconds. CloudWatch metrics show that the function's Duration is consistently around 28 seconds, but occasionally spikes to 35 seconds causing timeouts. The function makes a synchronous HTTP call to an external API. Which approach will MOST effectively prevent timeouts while maximizing throughput?
Answer choices
Why each option matters
Good practice is not just finding the correct option. The wrong answers often show the exact trap the exam wants you to fall into.
A
Best answer
Use async HTTP calls with a callback
Correct. Async calls allow the Lambda function to handle multiple HTTP requests concurrently, reducing overall execution time and preventing timeouts.
B
Distractor review
Increase the function's timeout to 60 seconds
Increasing timeout may prevent timeouts, but it does not improve efficiency and could increase costs. Also, it does not address the root cause of slow external calls.
C
Distractor review
Reduce the batch size to 5
Reducing batch size would lower the number of messages processed per invocation, decreasing throughput and potentially increasing cost due to more invocations.
D
Distractor review
Increase the SQS visibility timeout to 60 seconds
Visibility timeout controls how long a message is hidden from other consumers after being received. It does not affect the Lambda function's execution timeout.
Common exam trap
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.
Technical deep dive
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.
Related practice questions
Related DVA-C02 practice-question pages
Use these pages to review the topic behind this question. This is how one missed question becomes focused revision.
More questions from this exam
Keep practising from the same exam bank, or move into a focused topic page if this question exposed a weak area.
Question 1
A developer is building a REST API using Amazon API Gateway that will serve static content from an Amazon S3 bucket. The API should cache responses for frequently accessed objects to reduce latency. Which API Gateway feature should the developer enable?
Question 2
A developer is running a web application on multiple Amazon EC2 instances behind an Application Load Balancer (ALB). The application needs to store user session state that must be available across all instances. The session data is small and temporary but must survive individual instance failures. Which AWS service should the developer use to store this session state?
Question 3
A developer has an AWS Lambda function that processes messages from an Amazon SQS standard queue. The function is idempotent and currently has a batch size of 10. The developer wants to increase throughput and increases the batch size to 100. After the change, CloudWatch metrics show a significant increase in throttles and the queue backlog is growing. The function's reserved concurrency is set to 10. What is the most effective action to resolve the throttling and improve throughput?
Question 4
A developer is managing an application running on Amazon EC2 instances behind an Application Load Balancer. Users report that the application becomes unresponsive after several hours, and restarting the instance temporarily fixes the issue. The developer suspects a memory leak but cannot add custom instrumentation. Which AWS service can collect memory utilization metrics and help identify the memory leak with minimal configuration?
Question 5
A developer is building a serverless web application using AWS Lambda and Amazon DynamoDB. The application needs to perform complex aggregations on data stored in DynamoDB. Which AWS service should the developer use to perform these aggregations efficiently without reading all the data into Lambda?
Question 6
A developer has an Amazon S3 bucket containing private user documents. The application must generate a time-limited URL for users to download their own documents without requiring the users to have AWS credentials. Which solution should the developer use?
FAQ
Questions learners often ask
What does this DVA-C02 question test?
Read the scenario before looking for a memorised answer.
What is the correct answer to this question?
The correct answer is: Use async HTTP calls with a callback — The function's timeout is 30 seconds, and synchronous HTTP calls can take variable time. By using asynchronous HTTP calls, the function can initiate multiple requests concurrently and wait for all responses, reducing the total wall clock time. This allows processing more messages within the timeout, maximizing throughput. Increasing the timeout is possible but does not address the underlying latency and may hide issues. Reducing the batch size reduces throughput. Changing the SQS visibility timeout does not affect the Lambda function's execution timeout.
What should I do if I get this DVA-C02 question wrong?
Then try more questions from the same exam bank and focus on understanding why the wrong options are tempting.
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