Question 673 of 1,660
SAP-C02 Dead-letter queue (DLQ) Practice Question
A company uses AWS Lambda functions to process orders. Recently, some orders have been lost due to Lambda throttling. The operations team wants to implement a solution to capture failed invocations and retry them. What is the MOST reliable approach?
⚠ Common exam trap
Candidates often confuse EventBridge with SQS for managing retries, but SQS with a DLQ is the standard pattern for reliable invocation and failure handling in Lambda.
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
✓
Configure an SQS queue as the Lambda event source with a dead-letter queue for failed messages.
An SQS queue configured as a Lambda event source provides reliable invocation with retry logic, and a dead-letter queue (DLQ) captures messages that fail after all retries, preventing loss. Option A is wrong because CloudWatch Logs capture logs but do not capture or retry failed invocations. Option B is wrong because EventBridge can capture errors but does not provide built-in retry or a DLQ for Lambda throttling. Option D is wrong because SNS publishes messages but does not store them for retry; if the subscriber fails, the message is lost unless additional mechanisms are implemented.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Enable CloudWatch Logs for Lambda and create a metric filter to trigger an alarm.
Why it's wrong here
CloudWatch Logs only captures logs, not the failed invocations themselves.
- ✗
Use Amazon EventBridge to capture Lambda errors and route them to a recovery function.
Why it's wrong here
EventBridge does not automatically retry failed Lambda invocations.
- ✓
Configure an SQS queue as the Lambda event source with a dead-letter queue for failed messages.
Why this is correct
SQS provides reliable message delivery and retries; dead-letter queue captures messages that exceed retry attempts.
- ✗
Publish failed invocation details to an SNS topic and subscribe a Lambda function to process them.
Why it's wrong here
SNS does not store messages; if the subscriber fails, messages are lost.
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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Last reviewed: Jun 20, 2026
This SAP-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 SAP-C02 exam.
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