DVA-C02 AWS X-Ray SDK Practice Question
A developer is using AWS X-Ray to trace requests through a microservices application. The application consists of several AWS Lambda functions that call each other and Amazon DynamoDB. The developer notices that some traces are incomplete and missing segments for downstream calls. What is the MOST likely cause?
⚠ Common exam trap
The trap is that candidates often think DynamoDB tables have an X-Ray tracing toggle, but in reality, X-Ray tracing for DynamoDB is done by instrumenting the client with the X-Ray SDK. The most common cause of missing segments is failing to import and use the X-Ray SDK in Lambda functions.
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 functions do not have the X-Ray SDK imported.
The Lambda functions need to import the X-Ray SDK to create subsegments for downstream calls and propagate the trace header. Without the SDK, traces will be missing segments for DynamoDB calls. DynamoDB does not have a per-table X-Ray tracing setting; tracing is achieved by instrumenting the client in the calling code.
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 downstream DynamoDB table does not have X-Ray tracing enabled.
Why it's wrong here
This is incorrect. DynamoDB tables do not have an 'X-Ray tracing enabled' setting. X-Ray tracing for DynamoDB is achieved by instrumenting the DynamoDB client with the X-Ray SDK in the calling application.
- ✓
The Lambda functions do not have the X-Ray SDK imported.
Why this is correct
This is correct. If the Lambda functions do not import the X-Ray SDK, they cannot create segments or subsegments for downstream calls, leading to incomplete traces.
- ✗
The X-Ray daemon is not running on the Lambda execution environment.
Why it's wrong here
This is incorrect. The X-Ray daemon is automatically started by the Lambda runtime when X-Ray tracing is enabled for the function.
- ✗
The X-Ray sampling rate is set too low.
Why it's wrong here
This is less likely. A low sampling rate reduces the number of traces recorded, but for traces that are recorded, segments should be complete if the SDK is properly configured.
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 |
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Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
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.