CLF-C02 Database Services 5 — Questions and Answers
Question 1: Which pricing model for Amazon DynamoDB is best for applications with consistent, predictable traffic patterns?
- On-Demand Mode
- Provisioned Mode with Auto Scaling (Correct answer)
- Reserved Instances
- Spot Instances
Correct answer: Provisioned Mode with Auto Scaling
Provisioned Mode with Auto Scaling is cost-effective for predictable workloads as you specify expected read/write capacity and pay for reserved throughput.
Question 2: How does Amazon Aurora Global Database help multi-region applications?
- It stores data only in one region but serves reads globally via CDN
- It replicates data to secondary regions with less than 1 second lag for fast local reads (Correct answer)
- It automatically shards the database across all AWS regions
- It provides automatic schema migration across regions
Correct answer: It replicates data to secondary regions with less than 1 second lag for fast local reads
Aurora Global Database uses dedicated replication infrastructure to achieve sub-second replication lag to up to five secondary regions.
Question 3: A company stores user session data that should automatically expire after 24 hours. Which DynamoDB feature handles this without manual deletion?
- DynamoDB Streams
- DynamoDB Time to Live (TTL) (Correct answer)
- DynamoDB On-Demand
- DynamoDB Accelerator
Correct answer: DynamoDB Time to Live (TTL)
DynamoDB TTL automatically deletes items at a specified expiration timestamp, making it ideal for session data and temporary records.
Question 4: What is the key advantage of using Amazon Redshift Serverless compared to provisioned Redshift clusters?
- It supports more SQL functions than provisioned clusters
- It charges only when queries are running, with no idle cluster costs (Correct answer)
- It stores data in DynamoDB tables instead of columnar storage
- It only works with data stored in Amazon S3
Correct answer: It charges only when queries are running, with no idle cluster costs
Redshift Serverless automatically provisions capacity and charges only for the compute used during query execution, eliminating idle cluster costs.
Question 5: Which AWS service would you use to convert a Microsoft SQL Server database to an open-source engine like Aurora PostgreSQL?
- AWS Snowball
- AWS Schema Conversion Tool (SCT) (Correct answer)
- Amazon S3 Replication
- AWS Direct Connect
Correct answer: AWS Schema Conversion Tool (SCT)
AWS Schema Conversion Tool automatically converts your existing database schema and most of the application code to a new target database engine.
Question 6: What does the 'shared responsibility model' mean for Amazon RDS security?
- AWS manages everything including user data security and encryption
- AWS manages the infrastructure and database engine; the customer manages data, access, and encryption settings (Correct answer)
- The customer manages all aspects of database security including hardware
- AWS and the customer each manage 50% of all security controls
Correct answer: AWS manages the infrastructure and database engine; the customer manages data, access, and encryption settings
In RDS, AWS handles physical security, hardware, and patching while customers are responsible for data encryption, IAM access, and security group rules.
Question 7: Which statement accurately describes the difference between ElastiCache for Redis and ElastiCache for Memcached?
- Memcached supports persistence and replication; Redis does not
- Redis supports advanced data structures, persistence, and replication; Memcached is simpler and multi-threaded (Correct answer)
- Redis is only for SQL databases; Memcached works with NoSQL
- Both services are identical with no functional differences
Correct answer: Redis supports advanced data structures, persistence, and replication; Memcached is simpler and multi-threaded
Redis offers richer data types, persistence, pub/sub messaging, and replication, while Memcached is a simpler, multi-threaded cache for straightforward use cases.
CLF-C02 Database Services 5
Which pricing model for Amazon DynamoDB is best for applications with consistent, predictable traffic patterns?