Question 1hardmultiple choice
Full question →hardmultiple choiceObjective-mapped
A developer notices that an AWS Lambda function, which uses Amazon RDS Proxy to connect to an Aurora MySQL database, is experiencing increased latency and occasional connection timeouts. The function is configured with a reserved concurrency of 100 and is deployed in a VPC. The RDS Proxy's maximum connections is set to 1000. CloudWatch metrics show that the DatabaseConnections metric for the proxy is consistently at 1000. What is the most likely cause of the increased latency and timeouts?
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
The Lambda function is not reusing database connections properly, exhausting the proxy connection pool
Correct. Each invocation opens a new connection without reuse, causing the proxy to reach its connection limit.
B
Distractor review
The RDS Proxy target group is not configured with the correct DB instance
If misconfigured, connections would fail immediately, not cause gradual exhaustion.
C
Distractor review
The Lambda function's execution role is missing the rds-db:connect permission
Missing permissions would result in consistent connection failures, not gradual latency increase.
D
Distractor review
The VPC does not have a NAT Gateway for outbound traffic
NAT Gateway is needed for internet access, not for connecting to RDS Proxy within the same VPC.
Common exam trap
Common exam trap: NAT rules depend on direction and matching traffic
NAT is not only about the public address. The inside/outside interface roles and the ACL or rule that matches traffic are just as important.
Technical deep dive
How to think about this question
NAT questions usually test address translation, overload/PAT behaviour, static mappings and whether the right traffic is being translated. Read the interface direction and address terms carefully.
KKey Concepts to Remember
- Static NAT maps one inside address to one outside address.
- PAT allows many inside hosts to share one public address using ports.
- Inside local and inside global describe the private and translated addresses.
- NAT ACLs identify traffic for translation, not always security filtering.
TExam Day Tips
- Identify inside and outside interfaces first.
- Check whether the scenario needs static NAT, dynamic NAT or PAT.
- Do not confuse NAT matching ACLs with normal packet-filtering intent.
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?
Static NAT maps one inside address to one outside address.
What is the correct answer to this question?
The correct answer is: The Lambda function is not reusing database connections properly, exhausting the proxy connection pool — When the proxy's maximum connections are fully used, new connection requests are either queued or rejected, causing latency and timeouts. This often happens because the Lambda function creates a new database connection on each invocation without reusing existing connections, exhausting the connection pool. The reserved concurrency of 100 means up to 100 invocations can run concurrently, and if each opens a connection, it can quickly fill the pool. The target group configuration would cause different symptoms. Missing permissions would cause persistent failures. NAT Gateway is not required because RDS Proxy is accessible from within the VPC.
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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