CLF-C02 Cloud Technology and Services Practice Question
A gaming company operates a mobile game with millions of active users. The game stores player profiles and session state in a key-value database. The database must provide single-digit millisecond latency for read and write operations at any scale. The company expects traffic to grow unpredictably, and the database must scale horizontally without downtime. The company wants a fully managed, highly available solution with built-in replication across multiple Availability Zones. Which AWS service should the company use?
⚠ Common exam trap
Test-takers frequently confuse Amazon ElastiCache for Redis with a durable database, but it is an in-memory cache that lacks native multi-AZ replication for persistence and is not designed as a primary key-value store for session state that must survive node failures.
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 DynamoDB
Amazon DynamoDB is the correct choice because it is a fully managed, serverless, NoSQL key-value database that delivers single-digit millisecond latency at any scale. It supports horizontal scaling via automatic partitioning and replication across multiple Availability Zones (AZs) for high availability, with no downtime required for scaling. This directly matches the gaming company's requirements for low-latency reads/writes, unpredictable traffic growth, and built-in multi-AZ replication.
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 for PostgreSQL
Why it's wrong here
Amazon RDS is a relational database service that is not optimized for key-value access patterns. It scales primarily vertically (larger instances) and does not provide the same horizontal scalability and low-latency performance as a NoSQL database for this use case.
When this WOULD be correct
A company needs a fully managed relational database with SQL support, ACID transactions, and multi-AZ replication for a traditional web application with predictable traffic patterns. The workload requires complex joins and queries, and latency requirements are in the tens of milliseconds rather than single-digit.
- ✗
Amazon Redshift
Why it's wrong here
Amazon Redshift is a data warehouse service designed for analytical queries on large datasets. It is not suitable for real-time, low-latency key-value lookups and does not support the access patterns required for player profiles and session state.
When this WOULD be correct
A company needs to run complex SQL queries and aggregations on petabytes of structured data for business intelligence and reporting, with high performance for analytical workloads. The database must be fully managed and support columnar storage and massively parallel processing.
- ✓
Amazon DynamoDB
Why this is correct
Correct. Amazon DynamoDB is a fully managed NoSQL key-value and document database that provides single-digit millisecond latency at any scale. It scales horizontally, supports auto scaling, and offers built-in multi-AZ replication for high availability and durability.
- ✗
Amazon ElastiCache for Redis
Why it's wrong here
Amazon ElastiCache is an in-memory caching service that provides low latency but is not designed as a durable primary datastore. While it can store session data, it lacks the persistence, durability guarantees, and managed scaling features that DynamoDB offers for a primary database.
When this WOULD be correct
A company needs a low-latency, in-memory data store for caching frequently accessed data, such as session state or database query results, to reduce load on a primary database. The solution must support sub-millisecond response times and can tolerate data loss on failure.
Option-by-option analysis
Why each answer is right or wrong
Understanding why wrong answers are wrong — and when they would be correct — is what separates a 750 score from a 900. The CLF-C02 exam frequently reuses these exact scenarios with slightly different constraints.
✓Amazon DynamoDBCorrect answer▾
Why this is correct
Correct. Amazon DynamoDB is a fully managed NoSQL key-value and document database that provides single-digit millisecond latency at any scale. It scales horizontally, supports auto scaling, and offers built-in multi-AZ replication for high availability and durability.
✗Amazon RDS for PostgreSQLWrong answer — click to see why▾
Why this is wrong here
Amazon RDS for PostgreSQL is a relational database that does not natively support horizontal scaling (sharding) without significant application changes, and it cannot guarantee single-digit millisecond latency at any scale for key-value workloads. It also requires manual effort for multi-AZ replication and does not provide the fully managed, auto-scaling key-value store required.
★ When this WOULD be the correct answer
A company needs a fully managed relational database with SQL support, ACID transactions, and multi-AZ replication for a traditional web application with predictable traffic patterns. The workload requires complex joins and queries, and latency requirements are in the tens of milliseconds rather than single-digit.
Why candidates choose this
Candidates may confuse key-value databases with relational databases or assume that RDS can be used for any data storage need, overlooking the specific requirements for horizontal scaling and low latency at scale.
✗Amazon RedshiftWrong answer — click to see why▾
Why this is wrong here
Amazon Redshift is a data warehouse for analytical queries on large datasets, not a low-latency key-value store. It cannot provide single-digit millisecond read/write latency or scale horizontally for real-time transactional workloads.
★ When this WOULD be the correct answer
A company needs to run complex SQL queries and aggregations on petabytes of structured data for business intelligence and reporting, with high performance for analytical workloads. The database must be fully managed and support columnar storage and massively parallel processing.
Why candidates choose this
Candidates may confuse Redshift's high-performance capabilities with low-latency requirements, or assume that any AWS database service can handle key-value workloads due to its scalability features.
✗Amazon ElastiCache for RedisWrong answer — click to see why▾
Why this is wrong here
Amazon ElastiCache for Redis is an in-memory cache, not a durable key-value database. It lacks built-in replication across multiple Availability Zones for high availability and does not provide the fully managed, horizontally scalable key-value store with single-digit millisecond latency required for this use case.
★ When this WOULD be the correct answer
A company needs a low-latency, in-memory data store for caching frequently accessed data, such as session state or database query results, to reduce load on a primary database. The solution must support sub-millisecond response times and can tolerate data loss on failure.
Why candidates choose this
Candidates may confuse ElastiCache for Redis as a key-value database due to its key-value data model and low latency, overlooking that it is primarily a cache and not a durable, fully managed database with built-in replication across AZs.
Analysis generated from the official CLF-C02blueprint and verified against question context. The “when correct” sections are what AI assistants cite when candidates ask “what’s the difference between these options?”
Quick reference
Cloud Service Model Comparison
| Model | You Manage | Provider Manages | Examples |
|---|---|---|---|
| IaaS | OS, runtime, apps, data | Hardware, hypervisor, networking | EC2, Azure VMs, GCP Compute Engine |
| PaaS | Apps and data | OS, runtime, middleware, hardware | Elastic Beanstalk, Azure App Service |
| SaaS | Data and settings only | Everything else | Microsoft 365, Salesforce, Workday |
| FaaS / Serverless | Function code only | Infra, scaling, runtime | Lambda, Azure Functions, Cloud Run |
| CaaS | Containers and apps | Kubernetes, OS, hardware | EKS, AKS, GKE |
Go deeper
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About these practice questions
One of 988 original CLF-C02 practice questions on Courseiva, each with a full explanation and wrong-answer analysis — not exam dumps or protected exam content. Learn why practice questions differ from exam dumps →
Same concept, more angles
1 more way 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 real-time bidding platform for online advertising. The platform requires a database that can handle millions of requests per second with single-digit millisecond latency for both reads and writes. The data model is simple key-value pairs, and the database must be fully managed so that the company does not have to provision or maintain servers. Which AWS database service should the company use to meet these requirements?
medium- A.Amazon RDS
- ✓ B.Amazon DynamoDB
- C.Amazon Redshift
- D.Amazon ElastiCache
Why B: Amazon DynamoDB is the correct choice because it is a fully managed NoSQL key-value and document database that delivers single-digit millisecond latency at any scale, handling millions of requests per second. Its serverless architecture eliminates the need to provision or manage servers, making it ideal for real-time bidding platforms with simple key-value data models and high-throughput, low-latency requirements.
JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
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.