- A
Amazon DynamoDB Accelerator (DAX)
Why wrong: DAX is an in-memory cache for Amazon DynamoDB, not for Amazon RDS. It accelerates reads on DynamoDB tables but cannot be used with relational databases.
- B
Amazon ElastiCache
Amazon ElastiCache is a fully managed in-memory caching service that supports Redis and Memcached. It can be used to cache frequently accessed database query results, reducing the load on Amazon RDS and improving application response times.
- C
Amazon CloudFront
Why wrong: Amazon CloudFront is a content delivery network (CDN) that caches web content at edge locations to reduce latency for end users. It does not cache database query results from RDS.
- D
Amazon S3 Transfer Acceleration
Why wrong: Amazon S3 Transfer Acceleration speeds up uploads to Amazon S3 over long distances by using AWS edge locations. It is not used for caching database queries.
Quick Answer
The answer is Amazon ElastiCache, a fully managed, in-memory caching service that directly addresses the need to cache database query results and reduce RDS load. By storing frequently accessed query results in memory, ElastiCache allows read-heavy applications to retrieve data without repeatedly hitting the Amazon RDS database, which lowers CPU utilization and improves response times. On the AWS Certified Cloud Practitioner CLF-C02 exam, this scenario tests your understanding of how caching offloads read traffic from databases—a common pattern for scaling web applications. A typical trap is confusing ElastiCache with Amazon CloudFront (a CDN for static content) or RDS Read Replicas (which still query the database engine); remember that ElastiCache is for in-memory, sub-millisecond data retrieval, not for distributing static files or replicating full database instances. Memory tip: “Cache the hot data in memory” to keep ElastiCache top of mind when you see “reduce database load” and “frequently accessed queries.”
CLF-C02 Cloud Technology and Services Practice Question
This CLF-C02 practice question tests your understanding of cloud technology and services. Match the stated requirement to the specific cloud service, access model, or configuration option — many options are valid in isolation but not for this scenario. 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 runs a read-heavy web application on Amazon EC2 instances that queries an Amazon RDS database. As traffic grows, the database CPU utilization is consistently high, causing slow response times for users. The company wants to reduce the load on the database by caching frequently accessed query results. They need a fully managed, in-memory caching service that can be set up quickly and integrates with common programming languages. Which AWS service should they use?
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
Amazon ElastiCache
Amazon ElastiCache is a fully managed, in-memory caching service that supports Redis and Memcached, both of which integrate with common programming languages via standard client libraries. It can be deployed quickly to cache frequently accessed database query results, offloading read traffic from the Amazon RDS instance and reducing CPU utilization.
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.
- ✗
Amazon DynamoDB Accelerator (DAX)
Why it's wrong here
DAX is an in-memory cache for Amazon DynamoDB, not for Amazon RDS. It accelerates reads on DynamoDB tables but cannot be used with relational databases.
- ✓
Amazon ElastiCache
Why this is correct
Amazon ElastiCache is a fully managed in-memory caching service that supports Redis and Memcached. It can be used to cache frequently accessed database query results, reducing the load on Amazon RDS and improving application response times.
Related concept
Read the scenario before looking for a memorised answer.
- ✗
Amazon CloudFront
Why it's wrong here
Amazon CloudFront is a content delivery network (CDN) that caches web content at edge locations to reduce latency for end users. It does not cache database query results from RDS.
- ✗
Amazon S3 Transfer Acceleration
Why it's wrong here
Amazon S3 Transfer Acceleration speeds up uploads to Amazon S3 over long distances by using AWS edge locations. It is not used for caching database queries.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates may confuse DAX (a DynamoDB-specific cache) with a general-purpose cache, or think CloudFront can cache database query results, when in fact ElastiCache is the correct service for caching RDS query outputs in a read-heavy application.
Detailed technical explanation
How to think about this question
ElastiCache for Redis supports advanced data structures like sorted sets and hashes, enabling complex caching patterns such as leaderboards or session stores. In a read-heavy web application, implementing a cache-aside (lazy loading) pattern with ElastiCache can reduce database load by 80-90% for repeated queries, while also providing sub-millisecond response times. The service handles failover, patching, and backups automatically, making it a true fully managed solution.
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.
TExam Day Tips
- 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 media company stores terabytes of video archives that are accessed once a year for audit purposes. Moving these objects to a cold storage tier (Azure Archive, S3 Glacier, or Google Nearline) costs a fraction of hot storage. Questions like this test whether you understand storage tiers, access frequency tradeoffs, and retrieval latency requirements.
What to study next
Got this wrong? Here's your next step.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
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FAQ
Questions learners often ask
What does this CLF-C02 question test?
Cloud Technology and Services — This question tests Cloud Technology and Services — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Amazon ElastiCache — Amazon ElastiCache is a fully managed, in-memory caching service that supports Redis and Memcached, both of which integrate with common programming languages via standard client libraries. It can be deployed quickly to cache frequently accessed database query results, offloading read traffic from the Amazon RDS instance and reducing CPU utilization.
What should I do if I get this CLF-C02 question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
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Courseiva creates original exam-style practice questions with explanations and wrong-answer analysis. It does not publish real exam questions, exam dumps, or protected exam content. Learn why practice questions differ from exam dumps →
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Last reviewed: Jun 11, 2026
This CLF-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 CLF-C02 exam.
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