AWS Certified Database - Specialty practice test

1. Question 1 · 1

   A company has deployed an e-commerce web application in a new AWS account. An Amazon RDS for MySQL Multi-AZ DB instance is part of this deployment with a database-1.xxxxxxxxxxxx.us-east-1.rds.amazonaws.com endpoint listening on port 3306. The company's Database Specialist is able to log in to MySQL and run queries from the bastion host using these details. When users try to utilize the application hosted in the AWS account, they are presented with a generic error message. The application servers are logging a `could not connect to server: Connection times out` error message to Amazon CloudWatch Logs. What is the cause of this error?

   Choose one answer.

   • The user name and password the application is using are incorrect.
   • The security group assigned to the application servers does not have the necessary rules to allow inbound connections from the DB instance.
   • The security group assigned to the DB instance does not have the necessary rules to allow inbound connections from the application servers.
   • The user name and password are correct, but the user is not authorized to use the DB instance.

2. Question 2 · 1

   A Database Specialist is migrating a 2 TB Amazon RDS for Oracle DB instance to an RDS for PostgreSQL DB instance using AWS DMS. The source RDS Oracle DB instance is in a VPC in the us-east-1 Region. The target RDS for PostgreSQL DB instance is in a VPC in the use-west-2 Region. Where should the AWS DMS replication instance be placed for the MOST optimal performance?

   Choose one answer.

   • In the same Region and VPC of the source DB instance
   • In the same Region and VPC as the target DB instance
   • In the same VPC and Availability Zone as the target DB instance
   • In the same VPC and Availability Zone as the source DB instance

3. Question 3 · 1

   A company is using Amazon Aurora PostgreSQL for the backend of its application. The system users are complaining that the responses are slow. A database specialist has determined that the queries to Aurora take longer during peak times. With the Amazon RDS Performance Insights dashboard, the load in the chart for average active sessions is often above the line that denotes maximum CPU usage and the wait state shows that most wait events are IO:XactSync. What should the company do to resolve these performance issues?

   Choose one answer.

   • Add an Aurora Replica to scale the read traffic.
   • Scale up the DB instance class.
   • Modify applications to commit transactions in batches.
   • Modify applications to avoid conflicts by taking locks.

4. Question 4 · 1

   A database specialist deployed an Amazon RDS DB instance in Dev-VPC1 used by their development team. Dev-VPC1 has a peering connection with Dev-VPC2 that belongs to a different development team in the same department. The networking team confirmed that the routing between VPCs is correct; however, the database engineers in Dev-VPC2 are getting a timeout connections error when trying to connect to the database in Dev-VPC1. What is likely causing the timeouts?

   Choose one answer.

   • The database is deployed in a VPC that is in a different Region.
   • The database is deployed in a VPC that is in a different Availability Zone.
   • The database is deployed with misconfigured security groups.
   • The database is deployed with the wrong client connect timeout configuration.

5. Question 5 · 1

   A company has a production environment running on Amazon RDS for SQL Server with an in-house web application as the front end. During the last application maintenance window, new functionality was added to the web application to enhance the reporting capabilities for management. Since the update, the application is slow to respond to some reporting queries. How should the company identify the source of the problem?

   Choose one answer.

   • Install and configure Amazon CloudWatch Application Insights for Microsoft .NET and Microsoft SQL Server. Use a CloudWatch dashboard to identify the root cause.
   • Enable RDS Performance Insights and determine which query is creating the problem. Request changes to the query to address the problem.
   • Use AWS X-Ray deployed with Amazon RDS to track query system traces.
   • Create a support request and work with AWS Support to identify the source of the issue.

6. Question 6 · 1

   An electric utility company wants to store power plant sensor data in an Amazon DynamoDB table. The utility company has over 100 power plants and each power plant has over 200 sensors that send data every 2 seconds. The sensor data includes time with milliseconds precision, a value, and a fault attribute if the sensor is malfunctioning. Power plants are identified by a globally unique identifier. Sensors are identified by a unique identifier within each power plant. A database specialist needs to design the table to support an efficient method of finding all faulty sensors within a given power plant. Which schema should the database specialist use when creating the DynamoDB table to achieve the fastest query time when looking for faulty sensors?

   Choose one answer.

   • Use the plant identifier as the partition key and the measurement time as the sort key. Create a global secondary index (GSI) with the plant identifier as the partition key and the fault attribute as the sort key.
   • Create a composite of the plant identifier and sensor identifier as the partition key. Use the measurement time as the sort key. Create a local secondary index (LSI) on the fault attribute.
   • Create a composite of the plant identifier and sensor identifier as the partition key. Use the measurement time as the sort key. Create a global secondary index (GSI) with the plant identifier as the partition key and the fault attribute as the sort key.
   • Use the plant identifier as the partition key and the sensor identifier as the sort key. Create a local secondary index (LSI) on the fault attribute.

7. Question 7 · 1

   A company is releasing a new mobile game featuring a team play mode. As a group of mobile device users play together, an item containing their statuses is updated in an Amazon DynamoDB table. Periodically, the other users' devices read the latest statuses of their teammates from the table using the BatchGetltemn operation. Prior to launch, some testers submitted bug reports claiming that the status data they were seeing in the game was not up-to-date. The developers are unable to replicate this issue and have asked a database specialist for a recommendation. Which recommendation would resolve this issue?

   Choose one answer.

   • Ensure the DynamoDB table is configured to be always consistent.
   • Ensure the BatchGetltem operation is called with the ConsistentRead parameter set to false.
   • Enable a stream on the DynamoDB table and subscribe each device to the stream to ensure all devices receive up-to-date status information.
   • Ensure the BatchGetltem operation is called with the ConsistentRead parameter set to true.

8. Question 8 · 1

   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?

   Choose one answer.

   • Create an encrypted snapshot of the unencrypted DB instance. Copy the encrypted snapshot to Amazon S3. Restore the DB instance from the encrypted snapshot using Amazon S3.
   • Create a new RDS for MySQL DB instance with encryption enabled. Restore the unencrypted snapshot to this DB instance.
   • Create a snapshot of the unencrypted DB instance. Create an encrypted copy of the snapshot. Restore the DB instance from the encrypted snapshot.
   • Temporarily shut down the unencrypted DB instance. Enable AWS KMS encryption in the AWS Management Console using an AWS managed CMK. Restart the DB instance in an encrypted state.

9. Question 9 · 1

   A company is migrating its on-premises database workloads to the AWS Cloud. A database specialist performing the move has chosen AWS DMS to migrate an Oracle database with a large table to Amazon RDS. The database specialist notices that AWS DMS is taking significant time to migrate the data. Which actions would improve the data migration speed? (Choose three.)

   Choose all answers that apply.

   • Create multiple AWS DMS tasks to migrate the large table.
   • Configure the AWS DMS replication instance with Multi-AZ.
   • Increase the capacity of the AWS DMS replication server.
   • Establish an AWS Direct Connect connection between the on-premises data center and AWS.
   • Enable an Amazon RDS Multi-AZ configuration.
   • Enable full large binary object (LOB) mode to migrate all LOB data for all large tables.

10. Question 10 · 1

    A company is migrating a mission-critical 2-TB Oracle database from on premises to Amazon Aurora. The cost for the database migration must be kept to a minimum, and both the on-premises Oracle database and the Aurora DB cluster must remain open for write traffic until the company is ready to completely cut over to Aurora. Which combination of actions should a database specialist take to accomplish this migration as quickly as possible? (Choose two.)

    Choose all answers that apply.

    • Use the AWS Schema Conversion Tool (AWS SCT) to convert the source database schema. Then restore the converted schema to the target Aurora DB cluster.
    • Use Oracle's Data Pump tool to export a copy of the source database schema and manually edit the schema in a text editor to make it compatible with Aurora.
    • Create an AWS DMS task to migrate data from the Oracle database to the Aurora DB cluster. Select the migration type to replicate ongoing changes to keep the source and target databases in sync until the company is ready to move all user traffic to the Aurora DB cluster.
    • Create an AWS DMS task to migrate data from the Oracle database to the Aurora DB cluster. Once the initial load is complete, create an AWS Kinesis Data Firehose stream to perform change data capture (CDC) until the company is ready to move all user traffic to the Aurora DB cluster.
    • Create an AWS Glue job and related resources to migrate data from the Oracle database to the Aurora DB cluster. Once the initial load is complete, create an AWS DMS task to perform change data capture (CDC) until the company is ready to move all user traffic to the Aurora DB cluster.

11. Question 11 · 1

    A company has a 20 TB production Amazon Aurora DB cluster. The company runs a large batch job overnight to load data into the Aurora DB cluster. To ensure the company's development team has the most up-to-date data for testing, a copy of the DB cluster must be available in the shortest possible time after the batch job completes. How should this be accomplished?

    Choose one answer.

    • Use the AWS CLI to schedule a manual snapshot of the DB cluster. Restore the snapshot to a new DB cluster using the AWS CLI.
    • Create a dump file from the DB cluster. Load the dump file into a new DB cluster.
    • Schedule a job to create a clone of the DB cluster at the end of the overnight batch process.
    • Set up a new daily AWS DMS task that will use cloning and change data capture (CDC) on the DB cluster to copy the data to a new DB cluster. Set up a time for the AWS DMS stream to stop when the new cluster is current.

12. Question 12 · 1

    A company has two separate AWS accounts: one for the business unit and another for corporate analytics. The company wants to replicate the business unit data stored in Amazon RDS for MySQL in us-east-1 to its corporate analytics Amazon Redshift environment in us-west-1. The company wants to use AWS DMS with Amazon RDS as the source endpoint and Amazon Redshift as the target endpoint. Which action will allow AVS DMS to perform the replication?

    Choose one answer.

    • Configure the AWS DMS replication instance in the same account and Region as Amazon Redshift.
    • Configure the AWS DMS replication instance in the same account as Amazon Redshift and in the same Region as Amazon RDS.
    • Configure the AWS DMS replication instance in its own account and in the same Region as Amazon Redshift.
    • Configure the AWS DMS replication instance in the same account and Region as Amazon RDS.

13. Question 13 · 1

    The Development team recently executed a database script containing several data definition language (DDL) and data manipulation language (DML) statements on an Amazon Aurora MySQL DB cluster. The release accidentally deleted thousands of rows from an important table and broke some application functionality. This was discovered 4 hours after the release. Upon investigation, a Database Specialist tracked the issue to a DELETE command in the script with an incorrect WHERE clause filtering the wrong set of rows. The Aurora DB cluster has Backtrack enabled with an 8-hour backtrack window. The Database Administrator also took a manual snapshot of the DB cluster before the release started. The database needs to be returned to the correct state as quickly as possible to resume full application functionality. Data loss must be minimal. How can the Database Specialist accomplish this?

    Choose one answer.

    • Quickly rewind the DB cluster to a point in time before the release using Backtrack.
    • Perform a point-in-time recovery (PITR) of the DB cluster to a time before the release and copy the deleted rows from the restored database to the original database.
    • Restore the DB cluster using the manual backup snapshot created before the release and change the application configuration settings to point to the new DB cluster.
    • Create a clone of the DB cluster with Backtrack enabled. Rewind the cloned cluster to a point in time before the release. Copy deleted rows from the clone to the original database.

14. Question 14 · 1

    A database specialist is managing an application in the us-west-1 Region and wants to set up disaster recovery in the us-east-1 Region. The Amazon Aurora MySQL DB cluster needs an RPO of 1 minute and an RTO of 2 minutes. Which approach meets these requirements with no negative performance impact?

    Choose one answer.

    • Enable synchronous replication.
    • Enable asynchronous binlog replication.
    • Create an Aurora Global Database.
    • Copy Aurora incremental snapshots to the us-east-1 Region.

15. Question 15 · 1

    A gaming company is developing a new mobile game and decides to store the data for each user in Amazon DynamoDB. To make the registration process as easy as possible, users can log in with their existing Facebook or Amazon accounts. The company expects more than 10,000 users. How should a database specialist implement access control with the LEAST operational effort?

    Choose one answer.

    • Use web identity federation on the mobile app and AWS STS with an attached IAM role to get temporary credentials to access DynamoDB.
    • Use web identity federation on the mobile app and create individual IAM users with credentials to access DynamoDB.
    • Use a self-developed user management system on the mobile app that lets users access the data from DynamoDB through an API.
    • Use a single IAM user on the mobile app to access DynamoDB.

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