- A
Use Amazon DynamoDB Accelerator (DAX) as a caching layer.
Why wrong: DAX is an in-memory cache for DynamoDB but is designed for microsecond response times; however, it may be more expensive and not necessary if stale data is acceptable.
- B
Store frequently accessed items in an S3 bucket and read from S3.
Why wrong: S3 has higher latency and is not designed for low-latency caching.
- C
Set up an Amazon ElastiCache Memcached cluster and update the application to check the cache before reading from DynamoDB.
Memcached is a simple, scalable cache for read-heavy workloads with acceptable staleness.
- D
Use Amazon CloudFront to cache responses from the application.
Why wrong: CloudFront caches HTTP responses at edge locations, not database queries.
Question 1,378 of 1,616
Cache DynamoDB Reads with ElastiCache Memcached | AWS Developer Associate Explained
This DVA-C02 practice question tests your understanding of development with aws services. Read the scenario carefully and evaluate each option against the stated constraints before committing to an answer. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
A company is using Amazon DynamoDB as the database for a web application. The application reads and writes items based on a primary key. The traffic pattern shows that reads are 10 times more frequent than writes. The development team wants to reduce read latency and costs. They are considering adding a cache layer. The data is not sensitive, but stale data is acceptable for up to 5 minutes. The application runs on EC2 instances. What should the team do to implement caching?
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue:
"primary"Why it matters: Asks for the main purpose or function, not a secondary benefit. Eliminate answers that describe side-effects or partial 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
✓
Set up an Amazon ElastiCache Memcached cluster and update the application to check the cache before reading from DynamoDB.
Option C is correct because Amazon ElastiCache with Memcached is a distributed in-memory cache that can significantly reduce read latency for read-heavy workloads. By checking the cache before reading from DynamoDB, the application can serve frequent reads from ElastiCache, reducing load on DynamoDB and lowering costs. The allowable stale data of up to 5 minutes can be accommodated by setting a TTL on cached items. Option A, DAX, is also a caching solution but it is tightly integrated with DynamoDB and can be more expensive and less flexible than ElastiCache for this use case where cost reduction is a goal. Option B, storing data in S3, introduces higher latency and is not designed for low-latency caching of database queries. Option D, CloudFront, is a content delivery network for caching static assets at edge locations and does not reduce latency for database queries from the application.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Use Amazon DynamoDB Accelerator (DAX) as a caching layer.
Why it's wrong here
DAX is an in-memory cache for DynamoDB but is designed for microsecond response times; however, it may be more expensive and not necessary if stale data is acceptable.
- ✗
Store frequently accessed items in an S3 bucket and read from S3.
Why it's wrong here
S3 has higher latency and is not designed for low-latency caching.
- ✓
Set up an Amazon ElastiCache Memcached cluster and update the application to check the cache before reading from DynamoDB.
Why this is correct
Memcached is a simple, scalable cache for read-heavy workloads with acceptable staleness.
Clue confirmation
The clue word "primary" in the question point toward this answer.
Related concept
Read the scenario before looking for a memorised answer.
- ✗
Use Amazon CloudFront to cache responses from the application.
Why it's wrong here
CloudFront caches HTTP responses at edge locations, not database queries.
Common exam traps
Common exam trap: answer the scenario, not the keyword
Many certification questions include familiar terms but test a specific constraint. Read the exact wording before choosing an answer that is generally true but wrong for this case.
Detailed technical explanation
How to think about this question
This question should be treated as a scenario, not a definition check. Identify the problem, the constraint and the best action. Then compare each option against those facts.
KKey Concepts to Remember
- Read the scenario before looking for a memorised answer.
- Find the constraint that changes the correct option.
- Eliminate answers that are true in general but not in this case.
- Use explanations to understand the rule behind the answer.
TExam Day Tips
- Underline the problem statement mentally.
- Watch for words such as best, first, most likely and least administrative effort.
- Review why wrong options are wrong, not only why the correct option is correct.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
How this comes up in practice
A startup's cloud architect reviews their monthly bill and notices costs are higher than expected for a long-running batch job. Switching from on-demand instances to Reserved Instances — or using Spot/Preemptible VMs — can reduce compute costs by up to 72 %. Questions like this test whether you understand the tradeoffs between commitment, flexibility, and cost across cloud pricing models.
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 |
What to study next
Got this wrong? Here's your next step.
Identify which DVA-C02 exam domain this question belongs to, then review the specific concept being tested. Practise related questions in that domain and focus on understanding why each wrong answer is tempting — not just why the correct answer is right.
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FAQ
Questions learners often ask
What does this DVA-C02 question test?
Development with AWS Services — This question tests Development with AWS Services — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Set up an Amazon ElastiCache Memcached cluster and update the application to check the cache before reading from DynamoDB. — Option C is correct because Amazon ElastiCache with Memcached is a distributed in-memory cache that can significantly reduce read latency for read-heavy workloads. By checking the cache before reading from DynamoDB, the application can serve frequent reads from ElastiCache, reducing load on DynamoDB and lowering costs. The allowable stale data of up to 5 minutes can be accommodated by setting a TTL on cached items. Option A, DAX, is also a caching solution but it is tightly integrated with DynamoDB and can be more expensive and less flexible than ElastiCache for this use case where cost reduction is a goal. Option B, storing data in S3, introduces higher latency and is not designed for low-latency caching of database queries. Option D, CloudFront, is a content delivery network for caching static assets at edge locations and does not reduce latency for database queries from the application.
What should I do if I get this DVA-C02 question wrong?
Identify which DVA-C02 exam domain this question belongs to, then review the specific concept being tested. Practise related questions in that domain and focus on understanding why each wrong answer is tempting — not just why the correct answer is right.
Are there clue words in this question I should notice?
Yes — watch for: "primary". Asks for the main purpose or function, not a secondary benefit. Eliminate answers that describe side-effects or partial functions.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
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Last reviewed: Jun 20, 2026
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.
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