Jeff’s Note #
Unlike generic exam dumps, ADH analyzes this scenario through the lens of a Real-World Lead Developer.
For AWS DVA-C02 candidates, the confusion often lies in how to best reduce Lambda throttling without overcomplicating architecture or increasing latency.
In production, this is about knowing exactly which concurrency controls to adjust and when to request quota increases to keep functions running smoothly under load. Let’s drill down.
The Certification Drill (Simulated Question) #
Scenario #
TechSmart Solutions recently deployed a set of AWS Lambda functions handling user photo processing for their mobile app. After the initial rollout, their developers observed an increase in the Lambda throttle metrics visible in Amazon CloudWatch. This is causing delays in processing user uploads during peak traffic.
The Requirement: #
Identify the MOST operationally efficient ways to reduce Lambda function throttling while keeping operational overhead low.
The Options #
- A) Migrate the function workloads to Amazon Elastic Kubernetes Service (Amazon EKS).
- B) Increase the maximum age of events in the Lambda event source.
- C) Increase the function’s reserved concurrency limit.
- D) Add the lambda:GetFunctionConcurrency API permission to the function execution role.
- E) Request an increase in the Lambda concurrency service quota from AWS support.
Google adsense #
leave a comment:
Correct Answer #
C) Increase the function’s reserved concurrency.
E) Request an increase in the Lambda concurrency service quota from AWS support.
Quick Insight: The Developer Imperative #
Lambda concurrency throttling is an explicit limit on function instances running simultaneously.
Reserved concurrency guarantees capacity to your function, reducing throttling.
Additionally, AWS enforces account-level concurrency quotas, which can be increased on request for sustained higher load.
Other options either add operational complexity or are irrelevant to throttling control.
Content Locked: The Expert Analysis #
You’ve identified the answer. But do you know the implementation details that separate a Junior from a Senior?
The Expert’s Analysis #
Correct Answer #
Options C and E
The Winning Logic #
-
Option C: Increase reserved concurrency
Reserved concurrency directly allocates a fixed number of concurrent executions exclusively to a Lambda function. This prevents it being throttled by competition with other functions in the same account or region. It’s a simple setting change and operationally efficient to implement immediately. -
Option E: Request service quota increase
AWS imposes a default safety quota on total concurrency per region/account (usually 1,000 concurrent executions). If your workload grows beyond this, throttling occurs regardless of reserved concurrency. Submitting a service quota increase request is necessary to enable sustainable scaling.
The Trap (Distractor Analysis): #
-
Why not A?
Migrating to Amazon EKS introduces significant architectural complexity and operational overhead. It’s not an “operationally efficient” fix for throttling caused by concurrency limits in Lambda. -
Why not B?
Increasing the maximum age of events (e.g., for stream-based event sources) delays event processing but does not address throttling or concurrency directly. It’s irrelevant here. -
Why not D?
Adding thelambda:GetFunctionConcurrencypermission allows the function to call the API to retrieve its concurrency settings but does not reduce throttling itself. It’s a read-only permission and doesn’t change concurrency.
The Technical Blueprint #
Developer CLI Snippet to Adjust Reserved Concurrency: #
# Reserve 50 concurrent executions for Lambda function "PhotoProcessor"
aws lambda put-function-concurrency \
--function-name PhotoProcessor \
--reserved-concurrent-executions 50
Check Current Concurrency Limits: #
aws service-quotas get-service-quota \
--service-code lambda \
--quota-code L-54872343
Request Quota Increase via AWS Console or CLI: #
aws service-quotas request-service-quota-increase \
--service-code lambda \
--quota-code L-54872343 \
--desired-value 2000
The Comparative Analysis #
| Option | API Complexity | Performance Impact | Use Case |
|---|---|---|---|
| A | High (Container orchestration) | High latency, high overhead | Suitable for advanced containerized apps |
| B | None (Event source setting) | No direct effect on throttling | Event retry/dead-letter handling |
| C | Low (Lambda concurrency API) | Immediate throttling reduction | Short-term and predictable scale guarantee |
| D | Low (Permission addition) | No impact on throttling | Monitoring or introspective permissions |
| E | Medium (Quota management) | Enables higher scale long term | Necessary when workload grows beyond default |
Real-World Application (Practitioner Insight) #
Exam Rule #
For the exam, always pick reserved concurrency when you see Lambda throttling discussed alongside service quota considerations.
Real World #
In production, we often combine reserved concurrency with proactive quota increase requests to ensure smooth scaling during peak loads. Auto-scaling container solutions like EKS come with more operational cost and complexity, so they’re a longer-term roadmap, not a quick throttling fix.
(CTA) Stop Guessing, Start Mastering #
Disclaimer
This is a study note based on simulated scenarios for the AWS DVA-C02 exam.