Free DBS-C01 Practice Test Questions and Answers (2026) | Cert Empire

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DBS-C01.pdf

Q: 1

A company recently migrated its line-of-business (LOB) application to AWS. The application uses an Amazon RDS for SQL Server DB instance as its database engine. The company must set up cross-Region disaster recovery for the application. The company needs a solution with the lowest possible RPO and RTO. Which solution will meet these requirements?

Options

Q: 2

A financial company has allocated an Amazon RDS MariaDB DB instance with large storage capacity to accommodate migration efforts. Post-migration, the company purged unwanted data from the instance. The company now want to downsize storage to save money. The solution must have the least impact on production and near-zero downtime. Which solution would meet these requirements?

Options

Q: 3

An ecommerce company has tasked a Database Specialist with creating a reporting dashboard that visualizes critical business metrics that will be pulled from the core production database running on Amazon Auror a. Data that is read by the dashboard should be available within 100 milliseconds of an update. The Database Specialist needs to review the current configuration of the Aurora DB cluster and develop a cost-effective solution. The solution needs to accommodate the unpredictable read workload from the reporting dashboard without any impact on the write availability and performance of the DB cluster. Which solution meets these requirements?

Options

Q: 4

A gaming company has implemented a leaderboard in AWS using a Sorted Set data structure within Amazon ElastiCache for Redis. The ElastiCache cluster has been deployed with cluster mode disabled and has a replication group deployed with two additional replicas. The company is planning for a worldwide gaming event and is anticipating a higher write load than what the current cluster can handle. Which method should a Database Specialist use to scale the ElastiCache cluster ahead of the upcoming event?

Options

Q: 5

A database specialist is designing the database for a software-as-a-service (SaaS) version of an employee information application. In the current architecture, the change history of employee records is stored in a single table in an Amazon RDS for Oracle database. Triggers on the employee table populate the history table with historical records. This architecture has two major challenges. First, there is no way to guarantee that the records have not been changed in the history table. Second, queries on the history table are slow because of the large size of the table and the need to run the queries against a large subset of data in the table. The database specialist must design a solution that prevents modification of the historical records. The solution also must maximize the speed of the queries. Which solution will meet these requirements?

Options

Correct Answer:

Explanation

Correct Answer B

Explanation:

Explanation from Amazon documents:

Amazon Quantum Ledger Database (Amazon QLDB) is a fully managed ledger database that provides

a transparent, immutable, and cryptographically verifiable transaction log of all your application

changes. Amazon QLDB tracks each and every application data change and maintains a complete and

verifiable history of changes over time1. This makes it ideal for storing historical records that need to

be tamper-proof and auditable. Amazon QLDB also supports PartiQL, a SQL-compatible query

language that lets you query data using familiar SQL operators2.

Amazon OpenSearch Service (successor to Amazon Elasticsearch Service) is a fully managed service

that makes it easy to deploy, operate, and scale OpenSearch, an open source search and analytics

engine. Amazon OpenSearch Service lets you store, search, and analyze large volumes of data quickly

and at low cost3. You can use Amazon OpenSearch Service to index and query your employee record

history data stored in Amazon QLDB using the QLDB Streams feature. This way, you can leverage the

powerful search and analytics capabilities of OpenSearch Service to run fast and flexible queries on

your historical data.

Therefore, option B is the best solution that meets the requirements of preventing modification of

the historical records and maximizing the speed of the queries. Option A is not suitable because

DynamoDB is a key-value and document database that does not provide a ledger-like transaction log.

Option C is not suitable because Aurora PostgreSQL is a relational database that does not guarantee

immutability of the historical records. Option D is not suitable because Redshift is a data warehouse

that is optimized for analytical queries on large datasets, not for storing and querying individual

records.

Q: 6

A large ecommerce company uses Amazon DynamoDB to handle the transactions on its web portal. Traffic patterns throughout the year are usually stable; however, a large event is planned. The company knows that traffic will increase by up to 10 times the normal load over the 3-day event. When sale prices are published during the event, traffic will spike rapidly. How should a Database Specialist ensure DynamoDB can handle the increased traffic?

Options

Q: 7

A retail company manages a web application that stores data in an Amazon DynamoDB table. The company is undergoing account consolidation efforts. A database engineer needs to migrate the DynamoDB table from the current AWS account to a new AWS account. Which strategy meets these requirements with the LEAST amount of administrative work?

Options

Q: 8

A ride-hailing application stores bookings in a persistent Amazon RDS for MySQL DB instance. This program is very popular, and the corporation anticipates a tenfold rise in the application's user base over the next several months. The application receives a higher volume of traffic in the morning and evening. This application is divided into two sections: ✑ An internal booking component that takes online reservations in response to concurrent user queries. ✑ A component of a third-party customer relationship management (CRM) system that customer service professionals utilize. Booking data is accessed using queries in the CRM. To manage this workload effectively, a database professional must create a cost-effective database system. Which solution satisfies these criteria?

Options

Q: 9

A company is planning to migrate a 40 TB Oracle database to an Amazon Aurora PostgreSQL DB cluster by using a single AWS Database Migration Service (AWS DMS) task within a single replication instance. During early testing, AWS DMS is not scaling to the company's needs. Full load and change data capture (CDC) are taking days to complete. The source database server and the target DB cluster have enough network bandwidth and CPU bandwidth for the additional workload. The replication instance has enough resources to support the replication. A database specialist needs to improve database performance, reduce data migration time, and create multiple DMS tasks. Which combination of changes will meet these requirements? (Choose two.)

Options

Correct Answer:

Explanation

Correct Answer :- B and D

Explanation:

Explanation from Amazon documents:

AWS Database Migration Service (AWS DMS) is a service that helps you migrate data from one data

source to another. AWS DMS supports full load and change data capture (CDC) modes, which enable

you to migrate data with minimal downtime. AWS DMS also supports parallel load, which allows you

to load data from multiple tables or partitions concurrently.

To improve database performance, reduce data migration time, and create multiple DMS tasks, the

database specialist should use the following combination of changes:

Use a smaller set of tables with each DMS task. Set the MaxFullLoadSubTasks parameter to a higher

value. This change will allow the database specialist to split the migration workload into smaller and

more manageable units, and increase the parallelism of the full load process. The

MaxFullLoadSubTasks parameter specifies the maximum number of tables that are loaded in parallel

for each DMS task. By setting this parameter to a higher value, the database specialist can increase

the throughput and performance of the full load process.

Use parallel load with different data boundaries for larger tables. This change will allow the database

specialist to divide the larger tables into smaller chunks based on a partition key or a range of values,

and load them in parallel using multiple DMS tasks. Parallel load can significantly reduce the

migration time and improve the performance of large tables.

Therefore, option B and D are the correct combination of changes to meet the requirements. Option

A is incorrect because increasing the value of the ParallelLoadThreads parameter in the DMS task

settings for the tables will not improve the performance or reduce the migration time significantly.

The ParallelLoadThreads parameter specifies the number of threads that are used to load data from a

single table or partition. By increasing this parameter, the database specialist may increase the CPU

utilization and network bandwidth consumption of the source and target databases, but not the

parallelism of the full load process. Option C is incorrect because using a smaller set of tables with

each DMS task and setting the MaxFullLoadSubTasks parameter to a lower value will decrease the

parallelism and performance of the full load process. Option E is incorrect because running the DMS

tasks on a larger instance class and increasing local storage on the instance will not address the root

cause of the performance issue, which is the lack of parallelism and partitioning of the large tables.

Q: 10

A financial institution uses AWS to host its online application. Amazon RDS for MySQL is used to host the application's database, which includes automatic backups. The program has corrupted the database logically, resulting in the application being unresponsive. The exact moment the corruption occurred has been determined, and it occurred within the backup retention period. How should a database professional restore a database to its previous state prior to corruption?

Options

Q: 11

Recently, a financial institution created a portfolio management service. The application's backend is powered by Amazon Aurora, which supports MySQL. The firm demands a response time of five minutes and a response time of five minutes. A database professional must create a disaster recovery system that is both efficient and has a low replication latency. How should the database professional tackle these requirements?

Options

Q: 12

An internet advertising firm stores its data in an Amazon DynamoDb table. Amazon DynamoDB Streams are enabled on the table, and one of the keys has a global secondary index. The table is encrypted using a customer-managed AWS Key Management Service (AWS KMS) key. The firm has chosen to grow worldwide and want to duplicate the database using DynamoDB global tables in a new AWS Region. An administrator observes the following upon review: No role with the dynamodb: CreateGlobalTable permission exists in the account. An empty table with the same name exists in the new Region where replication is desired. A global secondary index with the same partition key but a different sort key exists in the new Region where replication is desired. Which settings will prevent you from creating a global table or replica in the new Region? (Select two.)

Options

Q: 13

A business is transferring its on-premises database workloads to the Amazon Web Services (AWS) Cloud. A database professional migrating an Oracle database with a huge table to Amazon RDS has picked AWS DMS. The database professional observes that AWS DMS is consuming considerable time migrating the data. Which activities would increase the pace of data migration? (Select three.)

Options

Q: 14

A company is running an Amazon RDS for MySQL Multi-AZ DB instance for a business-critical workload. RDS encryption for the DB instance is disabled. A recent security audit concluded that all business-critical applications must encrypt data at rest. The company has asked its database specialist to formulate a plan to accomplish this for the DB instance. Which process should the database specialist recommend?

Options

Q: 15

A company is building a software as a service application. As part of the new user sign-on workflow, a Python script invokes the CreateTable operation using the Amazon DynamoDB API. After the call returns, the script attempts to call PutItem. Occasionally, the PutItem request fails with a ResourceNotFoundException error, which causes the workflow to fail. The development team has confirmed that the same table name is used in the two API calls. How should a database specialist fix this issue?

Options

Q: 16

A company has a web application that uses Amazon API Gateway to route HTTPS requests to AWS Lambda functions. The application uses an Amazon Aurora MySQL database for its data storage. The application has experienced unpredictable surges in traffic that overwhelm the database with too many connection requests. The company needs to implement a scalable solution that is more resilient to database failures as quickly as possible. Which solution will meet these requirements MOST cost-effectively?

Options

Correct Answer:

Explanation

Correct Answer :- A

Explanation:

Explanation from Amazon documents:

Amazon Aurora Serverless is an on-demand, auto-scaling configuration for Amazon Aurora MySQL

that automatically starts up, shuts down, and scales capacity up or down based on your application’s

needs. Aurora Serverless is ideal for applications with unpredictable or intermittent traffic patterns

that experience sudden spikes or drops in demand. Aurora Serverless also provides high availability

and durability by replicating your data across multiple Availability Zones and continuously backing up

your data to Amazon S3.

Migrating the Aurora MySQL database to Amazon Aurora Serverless by restoring a snapshot will

meet the requirements of implementing a scalable solution that is more resilient to database failures

as quickly as possible. This solution will allow the company to benefit from the auto-scaling and high

availability features of Aurora Serverless, which will handle the unpredictable surges in traffic and

prevent connection issues. This solution will also be cost-effective, as the company will only pay for

the database capacity that they use. The migration process will be simple and fast, as the company

can use the AWS Management Console, the AWS CLI, or the RDS API to restore a snapshot of their

existing Aurora MySQL database to an Aurora Serverless DB cluster, and then change the endpoint in

the Lambda functions to use the new database.

Therefore, option A is the correct solution to meet the requirements. Option B is not cost-effective

because migrating the Aurora MySQL database to Amazon DynamoDB tables by using AWS DMS will

incur additional time and cost, and may require significant code changes to adapt to a different data

model and query language. Option C is not scalable because creating an EventBridge rule that

invokes a Lambda function to end any connections in the sleep state will not address the root cause

of the connection issues, which is the lack of database capacity to handle the traffic spikes. Option D

is not scalable because increasing the instance class for the Aurora database with more memory and

setting a larger value for the max_connections parameter will not provide auto-scaling or high

availability, and may still result in connection issues if the traffic exceeds the provisioned capacity.

Q: 17

A database specialist is responsible for an Amazon RDS for MySQL DB instance with one read replic a. The DB instance and the read replica are assigned to the default parameter group. The database team currently runs test queries against a read replica. The database team wants to create additional tables in the read replica that will only be accessible from the read replica to benefit the tests. Which should the database specialist do to allow the database team to create the test tables?

Options

Q: 18

A company wants to automate the creation of secure test databases with random credentials to be stored safely for later use. The credentials should have sufficient information about each test database to initiate a connection and perform automated credential rotations. The credentials should not be logged or stored anywhere in an unencrypted form. Which steps should a Database Specialist take to meet these requirements using an AWS CloudFormation template?

Options

Q: 19

A company has a reporting application that runs on an Amazon EC2 instance in an isolated developer account on AWS. The application needs to retrieve data during non-peak company hours from an Amazon Aurora PostgreSQL database that runs in the companys production account The companys security team requires that access to production resources complies with AWS best security practices A database administrator needs to provide the reporting application with access to the production database. The company has already configured VPC peering between the production account and developer account The company has also updated the route tables in both accounts With the necessary entries to correctly set up VPC peering What must the database administrator do to finish providing connectivity to the reporting application? Add an inbound security group rule to the database security group that allows access from the developer account VPC CIDR on port 5432. Add an outbound security group rule to the EC2 security group that allows access to the production account VPC CIDR on port 5432. Add an outbound security group rule to the database security group that allows access from the developer account VPC CIDR on port 5432. Add an outbound security group rule to the EC2 security group that allows access to the production account VPC CIDR on port 5432. Add an inbound security group rule to the database security group that allows access from the developer account VPC CIDR on all TCP ports. Add an inbound security group rule to the EC2 security group that allows access to the production account VPC CIDR on port 5432_ Add an inbound security group rule to the database security group that allows access from the developer account VPC CIDR on port 5432_ Add an outbound security group rule to the EC2 security group that allows access to the production account VPC CIDR on all TCP ports

Your Answer

Correct Answer:

Explanation

The correct answer is

A. Add an inbound security group rule to the database security group that allows access from the

developer account VPC CIDR on port 5432. Add an outbound security group rule to the EC2 security

group that allows access to the production account VPC CIDR on port 5432.

The explanation is as follows:

To allow the reporting application to access the production database, the database administrator

needs to configure the security group rules for both the database and the EC2 instance. The security

group rules must allow traffic between the peered VPCs on the port that the database uses, which is

5432 for PostgreSQL1.

Option A is correct because it adds an inbound rule to the database security group that allows access

from the developer account VPC CIDR on port 5432. This means that the database can accept

connections from the EC2 instance in the peered VPC. It also adds an outbound rule to the EC2

security group that allows access to the production account VPC CIDR on port 5432. This means that

the EC2 instance can initiate connections to the database in the peered VPC.

Option B is incorrect because it adds an outbound rule to the database security group, which is not

necessary. The database does not need to initiate connections to the EC2 instance, only accept them.

It also does not add an inbound rule to the EC2 security group, which is not required. The EC2

instance does not need to accept connections from the database, only initiate them.

Option C is incorrect because it adds an inbound rule to the database security group that allows

access from the developer account VPC CIDR on all TCP ports. This is too permissive and violates the

principle of least privilege2. It also adds an inbound rule to the EC2 security group that allows access

to the production account VPC CIDR on port 5432. This is unnecessary and does not help with

connectivity.

Option D is incorrect because it adds an outbound rule to the EC2 security group that allows access

to the production account VPC CIDR on all TCP ports. This is too permissive and violates the principle

of least privilege2. It also does not add an outbound rule to the database security group, which is not

needed.

Reference: 1: [Working with PostgreSQL and pgAdmin - Amazon Aurora] 2: [Security best practices in

IAM - AWS Identity and Access Management]

Q: 20

A company uses a large, growing, and high performance on-premises Microsoft SQL Server instance With an Always On availability group cluster size of 120 TIE. The company uses a third-party backup product that requires system-level access to the databases. The company will continue to use this third-party backup product in the future. The company wants to move the DB cluster to AWS with the least possible downtime and data loss. The company needs a 2 Gbps connection to sustain Always On asynchronous data replication between the company's data center and AWS. Which combination of actions should a database specialist take to meet these requirements? (Select THREE.) Establish an AWS Direct Connect hosted connection between the companfs data center and AWS Create an AWS Site-to-Site VPN connection between the companVs data center and AWS over the internet Use AWS Database Migration Service (AWS DMS) to migrate the on-premises SQL Server databases to Amazon RDS for SQL Server Configure Always On availability groups for SQL Server. Deploy a new SQL Server Always On availability group DB cluster on Amazon EC2 Configure Always On distributed availability groups between the on-premises DB cluster and the AWS DB cluster_ Fail over to the AWS DB cluster when it is time to migrate. Grant system-level access to the third-party backup product to perform backups of the Amazon RDS for SQL Server DB instance. Configure the third-party backup product to perform backups of the DB cluster on Amazon EC2.

Your Answer

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