DBS-C01 Practice Test 17 — 15 Questions

Question 1

A company's RDS for MySQL instance is experiencing high CPU utilization. Which AWS service should be used to set up automated actions to scale the instance vertically?

Accepted Answer

AWS Lambda function to modify the DB instance class. For automated vertical scaling of an RDS for MySQL instance, the most direct approach among the options is to use an AWS Lambda function that modifies the DB instance class, triggered by a CloudWatch alarm based on CPU utilization. AWS Auto Scaling (B) only supports horizontal scaling for RDS (adding read replicas) and does not natively change instance class. Systems Manager Automation (A) could orchestrate a change but is less straightforward than Lambda. CloudWatch Alarms (D) only notify; they cannot automatically scale without an action target like Lambda. Therefore, option C is the best choice.

Answer

AWS Systems Manager Automation with a custom runbook

Answer

AWS Auto Scaling with a target tracking scaling policy

Answer

Amazon CloudWatch Alarms to send an SNS notification to the DBA

Question 2

An e-commerce company uses Amazon RDS for MySQL to store order data. They need to run complex analytical queries on the data without impacting the performance of the transactional workload. Which TWO solutions should they implement? (Choose TWO.)

Accepted Answer

Use Amazon Redshift for analytics and load data via AWS DMS. Amazon Redshift is purpose-built for complex analytical queries on large datasets, and AWS DMS can continuously replicate data from RDS for MySQL into Redshift without impacting the source transactional workload. This separates OLTP and OLAP environments, ensuring performance isolation.

Answer

Migrate the transaction table to Amazon DynamoDB

Answer

Store order data in Amazon S3 and query with Amazon Athena

Answer

Enable Multi-AZ to use the standby for queries

Question 3

A company is running an Amazon RDS for SQL Server DB instance. The company needs to capture changes to a specific table and replicate them to an Amazon S3 bucket in near real time. Which AWS service should be used to achieve this?

Accepted Answer

AWS Database Migration Service (AWS DMS) with ongoing replication. AWS DMS with ongoing replication (change data capture) is the correct choice because it can continuously capture changes from the RDS for SQL Server source and replicate them to an Amazon S3 bucket in near real time. Option A (AWS Glue) is incorrect because AWS Glue is a batch ETL service, not designed for real-time change data capture. Option C (Amazon RDS for SQL Server native replication) is incorrect because native replication features like Always On Availability Groups or log shipping replicate data to another SQL Server instance, not directly to S3. Option D (Amazon Kinesis Data Streams) is incorrect because while it can ingest streaming data, it would require additional custom application logic to capture changes from RDS and push to Kinesis, making it less straightforward than DMS for this use case.

Answer

AWS Glue

Answer

Amazon RDS for SQL Server native replication

Answer

Amazon Kinesis Data Streams

Question 4

A company is deploying a new web application and needs a fully managed relational database with automatic failover and read replicas. Which AWS service should they choose?

Accepted Answer

Amazon RDS for MySQL with Multi-AZ deployment. Amazon RDS for MySQL with Multi-AZ deployment provides a fully managed relational database service that automatically provisions and maintains a synchronous standby replica in a different Availability Zone. In the event of a failure, Amazon RDS automatically fails over to the standby, ensuring high availability. Additionally, RDS for MySQL supports read replicas for offloading read traffic, which meets the requirement for both automatic failover and read replicas.

Answer

Amazon DynamoDB

Answer

Amazon EC2 with self-managed MySQL

Answer

Amazon Redshift

Question 5

A team is migrating an on-premises Microsoft SQL Server database to AWS. The database is used for reporting and analytics, with complex queries that join multiple tables. The team wants to minimize application changes and ensure compatibility. Which AWS service should they use?

Accepted Answer

Amazon RDS for SQL Server. Amazon RDS for SQL Server is the correct choice because it provides a managed SQL Server database engine that is fully compatible with on-premises SQL Server, minimizing application changes. The service supports complex queries with joins and reporting workloads without requiring code modifications, as it uses the same T-SQL dialect and features.

Answer

Amazon RDS for MySQL

Answer

Amazon Redshift

Answer

Amazon DynamoDB

Question 6

A company needs to store JSON documents that are up to 10 KB in size. The documents are accessed by a primary key, and the company requires single-digit millisecond latency. Which database service should be used?

Accepted Answer

Amazon DynamoDB. 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. It natively supports JSON documents up to 400 KB in size (well above the 10 KB requirement) and provides primary key access with consistent low-latency performance, making it ideal for this workload.

Answer

Amazon Neptune

Answer

Amazon S3

Answer

Amazon RDS for MySQL with JSON data type

Question 7

A company uses Amazon DynamoDB for a gaming application that stores player data. The application frequently accesses items by the player's user ID. However, the company also needs to query players by their subscription tier (Gold, Silver, Bronze) and registration date. Which design should the database specialist recommend for this access pattern?

Accepted Answer

Create a Global Secondary Index (GSI) on subscription tier and registration date.. A Global Secondary Index (GSI) on subscription tier and registration date is the correct choice because it allows efficient querying on non-primary key attributes without affecting the base table's primary key structure. DynamoDB GSIs support eventually consistent reads and can be created on any table, enabling the required access pattern of querying players by subscription tier and registration date while maintaining the primary access pattern by user ID.

Answer

Export the data to Amazon Elasticsearch Service for querying.

Answer

Create a Local Secondary Index (LSI) on subscription tier and registration date.

Answer

Enable DynamoDB Streams and process the stream to populate a separate table.

Question 8

A company wants to migrate its on-premises Oracle database to Amazon Aurora PostgreSQL. The company needs to convert the database schema and code from Oracle to PostgreSQL. Which AWS service should they use for schema conversion?

Accepted Answer

AWS Schema Conversion Tool (SCT). AWS Schema Conversion Tool (SCT) is the correct choice because it is specifically designed to convert database schemas, stored procedures, functions, and other code objects from one database engine to another, such as Oracle to Amazon Aurora PostgreSQL. It analyzes the source schema and generates a target schema with equivalent PostgreSQL syntax, handling data type mappings, PL/SQL to PL/pgSQL conversion, and other compatibility issues. AWS DMS handles data migration but does not perform schema or code conversion.

Answer

AWS DMS

Answer

AWS Glue

Answer

AWS Database Migration Service

Question 9

A company wants to migrate a 1 TB MySQL database to Amazon Aurora MySQL with minimal downtime. The database has a high write load. Which TWO options are valid approaches? (Choose two.)

Accepted Answer

Use AWS DMS with full load and ongoing replication.. AWS DMS supports full load and ongoing change data capture (CDC) replication, which can migrate the 1 TB MySQL database to Aurora MySQL with minimal downtime by continuously applying changes from the source binary logs. This approach handles high write loads efficiently by using transactional replication to keep the target nearly synchronized until cutover.

Answer

Export to flat files, transfer via AWS Snowball, and import.

Answer

Perform a mysqldump and restore to Aurora.

Answer

Use AWS SCT to convert the schema and then use DMS.

Question 10

A company has a self-managed Redis cluster that needs to be migrated to Amazon ElastiCache for Redis. The cluster is 100 GB in size and has a high write throughput. The migration must have minimal downtime. Which steps should be taken?

Accepted Answer

Set up replication from the source to ElastiCache using Redis replication. Redis replication (using the REPLICAOF or SLAVEOF command) allows you to set up the ElastiCache cluster as a read-replica of the self-managed Redis cluster, enabling continuous, asynchronous replication with minimal downtime. Once the replica is fully synchronized, you can promote it to the primary role with a brief failover, achieving a near-zero-downtime migration. This approach is ideal for a 100 GB cluster with high write throughput, as it avoids the performance impact of snapshotting or dump/restore operations.

Answer

Use AWS DMS to migrate the data with ongoing replication

Answer

Take a snapshot of the source and restore to ElastiCache

Answer

Use the SAVE command to create a dump, upload to S3, and import to ElastiCache

Question 11

A company uses Amazon DynamoDB as the primary database for a global gaming application. The application requires single-digit millisecond latency for user profile lookups by user ID. However, some queries need to retrieve all active users in a region (e.g., 'us-east-1') for administrative dashboards, and these queries currently perform full table scans, causing high costs and throttling. What design approach should be taken to optimize this?

Accepted Answer

Create a global secondary index (GSI) on the region attribute.. Creating a Global Secondary Index (GSI) on the 'region' attribute allows the administrative dashboard queries to retrieve all active users in a specific region using an efficient index scan instead of a full table scan. This reduces read capacity consumption, avoids throttling, and maintains single-digit millisecond latency for the indexed queries, while the base table remains optimized for user ID lookups.

Answer

Implement DynamoDB Accelerator (DAX) to cache the dashboard queries.

Answer

Increase the read capacity units (RCUs) on the base table.

Answer

Create a local secondary index (LSI) on the region attribute.

Question 12

A developer needs to allow an application running on EC2 to access an Amazon RDS database without storing database credentials in the application code. Which solution is the MOST secure?

Accepted Answer

Use IAM database authentication for the RDS instance and assign an IAM role to the EC2 instance.. IAM database authentication allows the EC2 instance to use an IAM role to authenticate to the RDS database, eliminating the need to store any credentials in the application code. This is the most secure method. Options B and C still rely on storing and retrieving a password, which introduces risk. Option D stores credentials in a config file, which is insecure.

Answer

Store the database password in AWS Systems Manager Parameter Store as a SecureString.

Answer

Store the database password in the application configuration file.

Answer

Store the database password in AWS Secrets Manager and enable automatic rotation.

Question 13

A company is running a critical application on Amazon RDS for Oracle. They need to ensure high availability with automatic failover in case of a database failure. The database size is 500 GB. Which solution should they implement?

Accepted Answer

Enable Multi-AZ deployment. Multi-AZ deployment for Amazon RDS for Oracle provides synchronous replication to a standby instance in a different Availability Zone, with automatic failover in the event of a database failure. This ensures high availability without manual intervention, meeting the requirement for automatic failover for a 500 GB Oracle database.

Answer

Create a cross-Region read replica

Answer

Migrate to Amazon DynamoDB Global Tables

Answer

Take regular snapshots and restore in a different Availability Zone

Question 14

A company is migrating a large Oracle data warehouse to Amazon Redshift. The source database has many complex stored procedures, views, and joins. Which THREE actions should the company take during the migration?

Accepted Answer

Use the AWS Schema Conversion Tool (SCT) to convert stored procedures.. AWS Schema Conversion Tool (SCT) is the recommended tool for converting Oracle stored procedures, functions, and packages to Amazon Redshift's PL/pgSQL-compatible language. It automates the translation of complex procedural logic, reducing manual effort and errors during migration. Redshift does not support Oracle-specific PL/SQL constructs natively, so SCT handles syntax and semantic conversion.

Answer

Migrate triggers as they are in Redshift.

Answer

Recreate all indexes from Oracle in Redshift.

Question 15

A financial services company needs a database for trade settlement records. Each trade must be processed exactly once and the database must ensure ACID compliance across multiple rows. The workload is write-intensive with moderate reads. Which AWS database service should they choose?

Accepted Answer

Amazon Aurora PostgreSQL. Amazon Aurora PostgreSQL is the correct choice because it provides full ACID compliance across multiple rows, which is essential for trade settlement records where each trade must be processed exactly once. Aurora PostgreSQL is a relational database that supports multi-row transactions with strong consistency, and its write-intensive workload performance is enhanced by a distributed storage subsystem that offloads redo log processing, making it suitable for high-throughput write operations while maintaining moderate read performance.

Answer

Amazon DynamoDB with DynamoDB transactions

Answer

Amazon ElastiCache for Redis

Answer

Amazon Neptune