Jeff’s Note #
Unlike generic exam dumps, ADH analyzes this scenario through the lens of a Real-World Lead Developer.
For DVA-C02 candidates, the confusion often lies in choosing the most efficient and least code-intensive method to handle data lifecycle. In production, this is about knowing exactly which AWS service features automate routine tasks like data expiry without custom code, reducing operational overhead. Let’s drill down.
The Certification Drill (Simulated Question) #
Scenario #
A digital polling startup, PollStream, runs its user feedback platform powered by DynamoDB to store daily user poll responses. Each poll response is relevant only until the poll results are published the next day. Afterward, PollStream no longer needs to keep these responses, and wants them removed automatically without manual intervention or complex coding.
The Requirement: #
The Lead Developer must implement a solution that automatically removes outdated poll responses from DynamoDB using a new attribute expiration_date. The solution should minimize development effort and operational complexity.
The Options #
- A) Create an AWS Lambda function to scan the DynamoDB table and delete expired user responses based on the
expiration_dateattribute. Schedule this Lambda to run daily using Amazon EventBridge. - B) Create an AWS Fargate task in Amazon ECS that deletes expired user responses based on the
expiration_dateattribute. Schedule this task daily with EventBridge. - C) Create an AWS Glue job to delete expired user responses based on the
expiration_dateattribute. Trigger the job daily with an AWS Glue schedule. - D) Enable DynamoDB Time To Live (TTL) feature on the table and specify the
expiration_dateattribute to automatically expire old user responses.
Google adsense #
leave a comment:
Correct Answer #
D
Quick Insight: The Developer Imperative #
- The TTL feature in DynamoDB is specifically designed for automatic and low-maintenance data expiry without writing any custom deletion code.
- Lambda or ECS solutions add complexity, operational overhead, and potential throttling or partial failures.
- Glue jobs would be an overkill and slow for this use case.
- Understanding DynamoDB TTL’s asynchronous, eventual deletion mechanism separates a good developer from a great one.
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 #
Option D
The Winning Logic #
DynamoDB’s Time To Live (TTL) feature allows developers to designate a timestamp attribute that determines when an item expires and is automatically deleted by DynamoDB’s background process. This removes the need for any polling, scanning, or explicit deletions in code, minimizing required development effort and operational complexity.
- No Lambda, Fargate, or Glue jobs need to be created or managed.
- TTL runs asynchronously and is designed for exactly this data lifecycle use case.
- Reduces risk of code bugs, bottlenecks in scanning, or accidental missed deletions.
- Designed for scale without additional cost or maintenance.
The Trap (Distractor Analysis): #
-
Why not A?
Lambda with scheduled scans requires coding, error handling, pagination for large tables, and manual retry logic. High operational burden for a simple TTL use case. -
Why not B?
Fargate task is overcomplicated and costly just to perform daily deletes. More complex infrastructure management than needed. -
Why not C?
Glue is intended for ETL and big data workflows. Running Glue for trivial deletions adds unnecessary latency, cost, and complexity.
The Technical Blueprint #
# Enable TTL on the DynamoDB table using AWS CLI
aws dynamodb update-time-to-live \
--table-name PollResponsesTable \
--time-to-live-specification Enabled=true,AttributeName=expiration_date
The Comparative Analysis #
| Option | API Complexity | Operational Overhead | Performance Impact | Use Case Suitability |
|---|---|---|---|---|
| A) Lambda | Medium (coding + scheduling) | Medium | Scan can cause latency/throttling | Works but overkill |
| B) Fargate task | High (infrastructure + coding) | High | Costly, complex orchestration | Overcomplicated |
| C) Glue job | High (ETL oriented) | High | Slow, expensive | Misfit for deletion |
| D) DynamoDB TTL | Low (config only) | Low | Built-in async deletion | Ideal for auto-expiry |
Real-World Application (Practitioner Insight) #
Exam Rule #
For the exam, always pick DynamoDB TTL when you see the keyword “automatic deletion” or “expiration” on DynamoDB items.
Real World #
In production, custom Lambda or container tasks might be used only if TTL’s asynchronous timing is insufficient for strict deletion compliance or auditing reasons. Otherwise, TTL is the natural choice for lifecycle management.
(CTA) Stop Guessing, Start Mastering #
Disclaimer
This is a study note based on simulated scenarios for the AWS DVA-C02 exam.