SAP-C02 Lambda Reserved Concurrency Practice Question
A company is designing a serverless application using AWS Lambda. The function needs to process files uploaded to an S3 bucket and store metadata in DynamoDB. The solution must handle up to 1,000 concurrent invocations. Which configuration should be used to avoid throttling?
⚠ Common exam trap
Candidates often confuse reserved concurrency with concurrency limits. Reserved concurrency guarantees a specific amount of concurrency for a function, while concurrency limits are account-wide. The question asks to avoid throttling, so reserved concurrency is the correct tool.
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
✓
Set reserved concurrency to 1,000
Setting reserved concurrency to 1,000 ensures that the Lambda function has its own dedicated concurrency pool of 1,000, preventing throttling as long as the account's regional concurrency limit is at least 1,000. Option A is unnecessary since the default limit is already 1,000. Option B (provisioned concurrency) addresses cold starts, not throttling. Option C (DLQ) handles failures after invocation, not prevention of throttling.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Request a concurrency limit increase from AWS Support
Why it's wrong here
Requesting a concurrency limit increase is unnecessary because the default concurrency limit is already 1,000, which meets the requirement. This option does not prevent throttling for a specific function; it increases the account-wide limit, but no increase is needed.
- ✗
Enable provisioned concurrency
Why it's wrong here
Provisioned concurrency addresses cold starts and ensures initial burst capacity, but does not guarantee a specific concurrency level to avoid throttling. It is not the correct tool for avoiding throttling due to high concurrency.
- ✗
Use a dead-letter queue (DLQ) to retry throttled requests
Why it's wrong here
Using a dead-letter queue (DLQ) handles failed invocations after throttling or errors, but does not prevent throttling from occurring. It is a recovery mechanism, not a prevention measure.
- ✓
Set reserved concurrency to 1,000
Why this is correct
Setting reserved concurrency to 1,000 guarantees that the Lambda function has its own dedicated concurrency pool of 1,000, preventing throttling as long as the account's regional concurrency limit is at least 1,000 (which it is by default). This ensures capacity for up to 1,000 concurrent invocations.
Quick reference
AWS S3 Storage Class Comparison
| Storage Class | Min Duration | Retrieval | Use Case |
|---|---|---|---|
| S3 Standard | None | Immediate | Frequently accessed data |
| S3 Standard-IA | 30 days | Immediate | Infrequent access, rapid retrieval |
| S3 One Zone-IA | 30 days | Immediate | Non-critical infrequent data |
| S3 Intelligent-Tiering | None | Immediate–hours | Unknown or changing access patterns |
| S3 Glacier Instant | 90 days | Milliseconds | Archive with instant retrieval |
| S3 Glacier Flexible | 90 days | Minutes–hours | Archive, flexible retrieval |
| S3 Glacier Deep Archive | 180 days | Hours | Long-term compliance archive |
Go deeper
Related to this question
About these practice questions
Courseiva writes every SAP-C02 question from scratch — 1,660 in total, each with an explanation and a wrong-answer breakdown. None are copied from real exams or dumps. Learn why practice questions differ from exam dumps →
JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
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.