Question 728 of 724
DVA-C02 Troubleshooting and Optimization Practice Question
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?
⚠ Common exam trap
The trap here is that candidates may focus on the reserved concurrency (100) versus proxy max connections (1000) and assume the numbers are fine, missing that the real issue is connection reuse per invocation, not the total count.
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
✓
The Lambda function is not reusing database connections properly, exhausting the proxy connection pool
The RDS Proxy's DatabaseConnections metric is consistently at 1000, which equals the proxy's maximum connections setting. This indicates the proxy connection pool is fully saturated. When all connections are in use, new connection requests from Lambda invocations must wait, causing increased latency, and if the wait exceeds the timeout, connection timeouts occur. The most likely cause is that the Lambda function is not reusing database connections (e.g., not using connection pooling or keeping connections open across invocations), exhausting the pool.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
The Lambda function is not reusing database connections properly, exhausting the proxy connection pool
Why this is correct
Lambda functions are inherently stateless and often short-lived. Without explicit connection pooling implemented within the Lambda function's code (e.g., by declaring the connection object in a global scope), each new invocation will attempt to establish a fresh connection to the RDS Proxy. This rapid creation of new client connections, especially under high concurrency, quickly exhausts the limited connection pool managed by the RDS Proxy, leading to connection failures and increased latency as requests wait for available connections.
- ✗
The RDS Proxy target group is not configured with the correct DB instance
Why it's wrong here
If the RDS Proxy's target group is incorrectly configured and points to a non-existent or inaccessible DB instance, any connection attempt from the Lambda function through the proxy would fail immediately and consistently. This scenario would manifest as immediate connection errors for all requests, rather than a gradual increase in latency or eventual exhaustion of the proxy's connection pool, as the proxy would be unable to establish its own backend connections to the database.
- ✗
The Lambda function's execution role is missing the rds-db:connect permission
Why it's wrong here
The `rds-db:connect` permission is essential for a Lambda function's execution role to successfully authenticate with RDS Proxy using IAM authentication. If this permission is missing, every single connection attempt from the Lambda function to the RDS Proxy would be met with an immediate authorization denial. This would result in consistent connection failures, preventing any database interactions, rather than a scenario of gradual performance degradation or connection pool exhaustion.
- ✗
The VPC does not have a NAT Gateway for outbound traffic
Why it's wrong here
A NAT Gateway is primarily used to provide outbound internet access to resources located in private subnets within a VPC. However, RDS Proxy and the RDS database instance are typically deployed within the same VPC as the Lambda function (or a peered VPC). Connections between resources residing within the same VPC, especially to private endpoints like RDS Proxy, do not require a NAT Gateway. Therefore, its absence would not impact the Lambda function's ability to connect to the RDS Proxy.
Quick reference
Cloud Service Model Comparison
| Model | You Manage | Provider Manages | Examples |
|---|---|---|---|
| IaaS | OS, runtime, apps, data | Hardware, hypervisor, networking | EC2, Azure VMs, GCP Compute Engine |
| PaaS | Apps and data | OS, runtime, middleware, hardware | Elastic Beanstalk, Azure App Service |
| SaaS | Data and settings only | Everything else | Microsoft 365, Salesforce, Workday |
| FaaS / Serverless | Function code only | Infra, scaling, runtime | Lambda, Azure Functions, Cloud Run |
| CaaS | Containers and apps | Kubernetes, OS, hardware | EKS, AKS, GKE |
About these practice questions
Courseiva creates original exam-style practice questions with explanations and wrong-answer analysis. It does not publish real exam questions, exam dumps, or protected exam content. Learn why practice questions differ from exam dumps →
Last reviewed: Jun 11, 2026
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.
Question Discussion
Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.
Sign in to join the discussion.