- A
Amazon RDS Read Replica
Why wrong: Read replicas distribute read traffic but still query the database engine. For caching query results that change infrequently, in-memory caching with ElastiCache is significantly faster and reduces database compute costs.
- B
Amazon S3
Why wrong: S3 is object storage, not an in-memory cache. While you could store cached data in S3, retrieval latency is much higher than an in-memory cache.
- C
Amazon ElastiCache
ElastiCache provides fully managed in-memory caching with Redis or Memcached. Caching the product catalogue in ElastiCache means most requests never reach the database, dramatically reducing latency and database load.
- D
Amazon DynamoDB
Why wrong: DynamoDB provides single-digit millisecond latency but is still a disk-backed database. For reducing relational database query load with sub-millisecond caching, ElastiCache (in-memory) is the appropriate service.
Quick Answer
Amazon ElastiCache is the correct choice because it provides an in-memory caching layer for database query results, using Redis or Memcached to store frequently accessed data and dramatically reduce latency for high-throughput read workloads. By caching query results in memory, ElastiCache offloads repeated requests from the relational database, directly addressing the bottleneck of thousands of queries per second on infrequently changing data. On the AWS Certified Cloud Practitioner CLF-C02 exam, this scenario tests your understanding of how in-memory caching improves application performance and reduces database load, often appearing as a contrast to services like Amazon RDS or DynamoDB Accelerator (DAX). A common trap is confusing ElastiCache with a database itself—remember, it is a cache, not a primary data store. Memory tip: think "ElastiCache = Elastic + Cache" to recall it scales in-memory storage for lightning-fast reads.
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 web application queries a relational database for a product catalogue that changes infrequently but is requested thousands of times per second. Database query latency is becoming a bottleneck. Which AWS service can the company use to cache frequently accessed query results in memory and reduce database load?
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 the correct choice because it provides an in-memory caching layer (using Redis or Memcached) that can store frequently accessed query results, reducing the need to repeatedly query the relational database. This dramatically lowers latency for high-throughput read workloads (thousands of requests per second) and offloads database pressure, directly addressing the bottleneck described.
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 RDS Read Replica
Why it's wrong here
Read replicas distribute read traffic but still query the database engine. For caching query results that change infrequently, in-memory caching with ElastiCache is significantly faster and reduces database compute costs.
- ✗
Amazon S3
Why it's wrong here
S3 is object storage, not an in-memory cache. While you could store cached data in S3, retrieval latency is much higher than an in-memory cache.
- ✓
Amazon ElastiCache
Why this is correct
ElastiCache provides fully managed in-memory caching with Redis or Memcached. Caching the product catalogue in ElastiCache means most requests never reach the database, dramatically reducing latency and database load.
Related concept
Read the scenario before looking for a memorised answer.
- ✗
Amazon DynamoDB
Why it's wrong here
DynamoDB provides single-digit millisecond latency but is still a disk-backed database. For reducing relational database query load with sub-millisecond caching, ElastiCache (in-memory) is the appropriate service.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates often confuse a read replica (Option A) with a caching solution, not realizing that a read replica still executes SQL queries against a relational engine and does not provide the in-memory speed needed for thousands of requests per second.
Detailed technical explanation
How to think about this question
ElastiCache for Redis supports operations like SET/GET with TTL (time-to-live) to automatically expire stale cache entries, and can use a lazy caching or write-through pattern to keep data fresh. Under the hood, Redis stores data entirely in RAM, enabling sub-millisecond response times, and can handle hundreds of thousands of operations per second on a single node. In a real-world scenario, a product catalogue that changes infrequently would benefit from a cache-aside pattern where the application checks ElastiCache first, and only queries the database on a cache miss, reducing database load by over 90%.
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.
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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 the correct choice because it provides an in-memory caching layer (using Redis or Memcached) that can store frequently accessed query results, reducing the need to repeatedly query the relational database. This dramatically lowers latency for high-throughput read workloads (thousands of requests per second) and offloads database pressure, directly addressing the bottleneck described.
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.
About these practice questions
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 →
Same concept, more angles
1 more ways this is tested on CLF-C02
These questions test the same concept from different angles. Work through them to make sure you can recognise it however the exam phrases it.
Variation 1. A company runs a high-traffic e-commerce application. During peak holiday season, database read performance degrades. They want to offload read traffic from their RDS primary database. What should they implement?
medium- A.RDS Multi-AZ
- ✓ B.RDS Read Replicas
- C.Increase the RDS instance size
- D.Enable RDS Automated Backups
Why B: B is correct because RDS Read Replicas are specifically designed to offload read traffic from the primary database instance. By creating one or more read-only replicas, the application can direct SELECT queries to the replicas, reducing the load on the primary RDS instance and improving overall read performance during peak traffic.
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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