AWS - Certified Solutions Architect Database Services and Migration Questions and Answers

Question 1

A company is planning to migrate a 10TB on-premises Oracle database to Amazon Aurora PostgreSQL. The migration must be completed with minimal downtime. The source database contains numerous stored procedures and functions specific to Oracle's PL/SQL. What is the correct sequence of actions using AWS services to achieve this migration?

Accepted Answer

Use the AWS Schema Conversion Tool (SCT) to convert the schema and code objects, then use AWS Database Migration Service (DMS) to migrate the data.

Answer

For a heterogeneous migration (Oracle to PostgreSQL) with minimal downtime, the correct approach involves two main steps. First, use the AWS Schema Conversion Tool (SCT) to assess and convert the source schema and custom code (like PL/SQL stored procedures) to a format compatible with the target database (Aurora PostgreSQL). Second, use the AWS Database Migration Service (DMS) to perform the full data load and then capture and apply ongoing changes (Change Data Capture - CDC) from the source to the target, which keeps the databases synchronized and minimizes downtime during the final cutover.

Question 2

A popular e-commerce website uses an Amazon RDS for MySQL database. During peak shopping events, the website experiences slow performance due to a high volume of read traffic, which impacts the primary database's ability to handle write operations. The company needs a solution to improve read performance and offload queries from the primary database instance. Which RDS feature is specifically designed to address this requirement?

Accepted Answer

Creating Read Replicas

Answer

Read Replicas are designed specifically for scaling read-heavy workloads. They are asynchronous copies of the primary database instance that can serve read traffic, thereby reducing the load on the primary instance and improving overall performance. While Multi-AZ provides high availability and disaster recovery, the standby instance cannot be used to serve read traffic. Increasing instance size or switching to PIOPS can help performance but do not address the fundamental issue of offloading read queries.

Question 3

A development team is building a new mobile gaming application that requires a database for storing player scores and session data. The application needs extremely low latency (single-digit milliseconds) for both reads and writes, and it must scale seamlessly to handle millions of users with unpredictable traffic patterns. Which AWS database service is the most appropriate choice for this use case?

Accepted Answer

Amazon DynamoDB

Answer

Amazon DynamoDB is a fully managed NoSQL database service that provides fast and predictable performance with seamless scalability. It is designed for applications that require consistent, single-digit millisecond latency at any scale, making it ideal for use cases like mobile gaming, ad tech, and session stores. RDS is a relational database and may not provide the same level of low-latency performance at massive scale for this access pattern. Redshift is a data warehouse for analytics, and S3 is an object store, not a low-latency database.

Question 4

A financial services company is running a critical OLTP application on Amazon RDS for MySQL. They are looking to improve performance, scalability, and availability beyond what standard RDS offers. They want a solution that is MySQL-compatible, provides significantly higher throughput, and has a self-healing, fault-tolerant storage architecture distributed across three Availability Zones. Which AWS database service should they migrate to?

Accepted Answer

Amazon Aurora

Answer

Amazon Aurora is a MySQL and PostgreSQL-compatible relational database built for the cloud. It provides the performance and availability of commercial databases at a fraction of the cost. Key features include up to 5x the throughput of standard MySQL, a fault-tolerant and self-healing storage system that replicates six copies of data across three Availability Zones, and low-latency read replicas. This directly matches the requirements for improved performance, scalability, and availability while maintaining MySQL compatibility.

Question 5

An application is built on Amazon EC2 instances with an Amazon RDS for PostgreSQL database as its backend. Performance monitoring reveals that the database is under heavy load due to a large number of repetitive read queries for frequently accessed data, such as user profiles and product catalogs. This is causing high latency for all users. What is the most effective way to improve application latency by reducing the load on the RDS database?

Accepted Answer

Implement Amazon ElastiCache to serve as an in-memory cache.

Answer

Amazon ElastiCache is a fully managed in-memory caching service designed to improve the performance of web applications by retrieving information from fast, managed, in-memory caches, instead of relying on slower disk-based databases. By caching the results of frequent queries, ElastiCache can significantly reduce the read load on the RDS database, decrease latency, and improve overall application performance. While Read Replicas can help, an in-memory cache is often more effective and faster for highly repetitive queries.

AWS Practice Test

AWS Practice Test

AWS - Certified Solutions Architect Database Services and Migration Questions and Answers