Amazon DBS-C01 Online Practice Questions and Exam Preparation

Amazon DBS-C01 Online Questions & Answers

• Question 161:

  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?

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

  ---

  Explanation/Reference:

  https://docs.aws.amazon.com/AmazonRDS/latest/AuroraUserGuide/AuroraPostgreSQL.Re ference.html https://blog.dbi-services.com/aws-aurora-xactsync-batch-commit/

• Question 162:

  A company is running a finance application on an Amazon RDS for MySQL DB instance. The application is governed by multiple financial regulatory agencies. The RDS DB instance is set up with security groups to allow access to certain

  Amazon EC2 servers only.

  AWS KMS is used for encryption at rest.

  Which step will provide additional security?

  A. Set up NACLs that allow the entire EC2 subnet to access the DB instance
  B. Disable the master user account
  C. Set up a security group that blocks SSH to the DB instance
  D. Set up RDS to use SSL for data in transit
  D. Set up RDS to use SSL for data in transit

  ---

  Explanation/Reference:

  Reference: https://aws.amazon.com/blogs/database/applying-best-practices-for-securing- sensitive-data-in- amazon-rds/

• Question 163:

  A company migrated an on-premises Oracle database to Amazon RDS for Oracle. A database specialist needs to monitor the latency of the database.

  Which solution will meet this requirement with the LEAST operational overhead?

  A. Publish RDS Performance insights metrics to Amazon CloudWatch. Add AWS CloudTrail filters to monitor database performance
  B. Install Oracle Statspack. Enable the performance statistics feature to collect, store, and display performance data to monitor database performance.
  C. Enable RDS Performance Insights to visualize the database load. Enable Enhanced Monitoring to view how different threads use the CPU
  D. Create a new DB parameter group that includes the AllocatedStorage, DBInstanceClassMemory, and DBInstanceVCPU variables. Enable RDS Performance Insights
  C. Enable RDS Performance Insights to visualize the database load. Enable Enhanced Monitoring to view how different threads use the CPU

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  Explanation/Reference:

  Correct Answer: C from Amazon documents: Amazon RDS for Oracle is a fully managed relational database service that supports Oracle Database. Amazon RDS for Oracle provides several features to monitor the performance and health of your database, such as RDS Performance Insights, Enhanced Monitoring, Amazon CloudWatch, and AWS CloudTrail. RDS Performance Insights is a feature that helps you quickly assess the load on your database and determine when and where to take action. RDS Performance Insights displays a dashboard that shows the database load in terms of average active sessions (AAS), which is the average number of sessions that are actively running SQL statements at any given time. RDS Performance Insights also shows the top SQL statements, waits, hosts, and users that are contributing to the database load. Enhanced Monitoring is a feature that provides metrics in real time for the operating system (OS) that your DB instance runs on. Enhanced Monitoring metrics include CPU utilization, memory, file system, disk I/O, network I/O, process list, and thread count. Enhanced Monitoring allows you to view how different threads use the CPU and how much memory each thread consumes. By enabling RDS Performance Insights and Enhanced Monitoring for the RDS for Oracle DB instance, the database specialist can monitor the latency of the database with the least operational overhead. This solution will allow the database specialist to use the RDS console or API to enable these features and view the metrics and dashboards without installing any additional software or tools. This solution will also provide comprehensive and granular information about the database load and resource utilization. Therefore, option C is the correct solution to meet the requirement. Option A is not optimal because publishing RDS Performance Insights metrics to Amazon CloudWatch and adding AWS CloudTrail filters to monitor database performance will incur additional operational overhead and cost. Amazon CloudWatch is a service that collects monitoring and operational data in the form of logs, metrics, and events. AWS CloudTrail is a service that records AWS API calls for your account and delivers log files to you. These services are useful for monitoring performance trends and auditing activities, but they are not necessary for monitoring latency in real time. Option B is not optimal because installing Oracle Statspack and enabling the performance statistics feature will require manual intervention and configuration on the RDS for Oracle DB instance. Oracle Statspack is a tool that collects, stores, and displays performance data for Oracle Database. The performance statistics feature is an option that enables Statspack to collect additional statistics such as wait events, latches, SQL statements, segments, rollback segments, etc. These tools are useful for performance tuning and troubleshooting, but they are not as easy to use as RDS Performance Insights and Enhanced Monitoring. Option D is not relevant because creating a new DB parameter group that includes the AllocatedStorage, DBInstanceClassMemory, and DBInstanceVCPU variables will not help monitor the latency of the database. A DB parameter group is a collection of DB engine configuration values that define how a DB instance operates. The AllocatedStorage parameter specifies the allocated storage size in gibibytes (GiB). The DBInstanceClassMemory parameter specifies the amount of memory available to an instance class in bytes. The DBInstanceVCPU parameter specifies the number of virtual CPUs available to an instance class. These parameters are used to configure the capacity and performance of a DB instance, but they do not provide any monitoring or metrics information. Enabling RDS Performance Insights alone will not provide enough information about the OS-level metrics such as CPU utilization or memory usage.

• Question 164:

  In one AWS account, a business runs a two-tier ecommerce application. An Amazon RDS for MySQL Multi-AZ database instance serves as the application's backend. A developer removed the database instance in the production

  environment by accident. Although the organization recovers the database, the incident results in hours of outage and financial loss.

  Which combination of adjustments would reduce the likelihood that this error will occur again in the future? (Select three.)

  A. Grant least privilege to groups, IAM users, and roles.
  B. Allow all users to restore a database from a backup.
  C. Enable deletion protection on existing production DB instances.
  D. Use an ACL policy to restrict users from DB instance deletion.
  E. Enable AWS CloudTrail logging and Enhanced Monitoring.
  A. Grant least privilege to groups, IAM users, and roles.
  C. Enable deletion protection on existing production DB instances.
  D. Use an ACL policy to restrict users from DB instance deletion.

• Question 165:

  Recently, a gaming firm purchased a popular iOS game that is especially popular during the Christmas season. The business has opted to include a leaderboard into the game, which will be powered by Amazon DynamoDB. The application's load is likely to increase significantly throughout the Christmas season.

  Which solution satisfies these criteria at the lowest possible cost?

  A. DynamoDB Streams
  B. DynamoDB with DynamoDB Accelerator
  C. DynamoDB with on-demand capacity mode
  D. DynamoDB with provisioned capacity mode with Auto Scaling
  D. DynamoDB with provisioned capacity mode with Auto Scaling

  ---

  Explanation/Reference:

  "On-demand is ideal for bursty, new, or unpredictable workloads whose traffic can spike in seconds or minutes"

  vs.

  'DynamoDB released auto scaling to make it easier for you to manage capacity efficiently, and auto scaling continues to help DynamoDB users lower the cost of workloads that have a predictable traffic pattern."

  https://aws.amazon.com/blogs/database/amazon-dynamodb-auto-scaling-performance- and-cost-optimization-at-any-scale/

• Question 166:

  A company is running an on-premises application comprised of a web tier, an application tier, and a MySQL database tier. The database is used primarily during business hours with random activity peaks throughout the day. A database

  specialist needs to improve the availability and reduce the cost of the MySQL database tier as part of the company's migration to AWS.

  Which MySQL database option would meet these requirements?

  A. Amazon RDS for MySQL with Multi-AZ
  B. Amazon Aurora Serverless MySQL cluster
  C. Amazon Aurora MySQL cluster
  D. Amazon RDS for MySQL with read replica
  C. Amazon Aurora MySQL cluster

• Question 167:

  A business is launching a new Amazon RDS for SQL Server database instance. The organization wishes to allow auditing of the SQL Server database. Which measures should a database professional perform in combination to achieve this requirement? (Select two.)

  A. Create a service-linked role for Amazon RDS that grants permissions for Amazon RDS to store audit logs on Amazon S3.
  B. Set up a parameter group to configure an IAM role and an Amazon S3 bucket for audit log storage. Associate the parameter group with the DB instance.
  C. Disable Multi-AZ on the DB instance, and then enable auditing. Enable Multi-AZ after auditing is enabled.
  D. Disable automated backup on the DB instance, and then enable auditing. Enable automated backup after auditing is enabled.
  E. Set up an options group to configure an IAM role and an Amazon S3 bucket for audit log storage. Associate the options group with the DB instance.
  A. Create a service-linked role for Amazon RDS that grants permissions for Amazon RDS to store audit logs on Amazon S3.
  E. Set up an options group to configure an IAM role and an Amazon S3 bucket for audit log storage. Associate the options group with the DB instance.

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  Explanation/Reference:

  https://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/Appendix.SQLServer.Options .Audit.html https://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/security_iam_service-with- iam.html

• Question 168:

  An ecommerce company is running Amazon RDS for Microsoft SQL Server. The company is planning to perform testing in a development environment with production data. The development environment and the production environment are in separate AWS accounts. Both environments use AWS Key Management Service (AWS KMS) encrypted databases with both manual and automated snapshots. A database specialist needs to share a KMS encrypted production RDS snapshot with the development account.

  Which combination of steps should the database specialist take to meet these requirements? (Select THREE.)

  A. Create an automated snapshot. Share the snapshot from the production account to the development account.
  B. Create a manual snapshot. Share the snapshot from the production account to the development account.
  C. Share the snapshot that is encrypted by using the development account default KMS encryption key.
  D. Share the snapshot that is encrypted by using the production account custom KMS encryption key.
  E. Allow the development account to access the production account KMS encryption key.
  F. Allow the production account to access the development account KMS encryption key.
  B. Create a manual snapshot. Share the snapshot from the production account to the development account.
  D. Share the snapshot that is encrypted by using the production account custom KMS encryption key.
  E. Allow the development account to access the production account KMS encryption key.

  ---

  Explanation/Reference:

  Correct Answer: B, D, E

  from Amazon documents:

  To share an encrypted Amazon RDS snapshot with another account, you need to do the following123:

  Create a manual snapshot of the production database. You can't share an automated snapshot directly, but you can copy it to a manual snapshot and then share it1.

  Use a custom KMS encryption key for the manual snapshot. You can't share a snapshot that is encrypted using the default KMS key of the source account1. Share the snapshot with the development account by specifying the account ID of

  the target account1.

  Allow the development account to access the custom KMS key of the source account by adding the target account ID to the key policy of the source account2. Copy the shared snapshot to the development account by using a KMS key of the

  target account2.

  Therefore, option B, D, and E are the correct steps to meet the requirements. Option A is incorrect because you can't share an automated snapshot. Option C is incorrect because you can't share a snapshot that is encrypted using the default

  KMS key. Option F is unnecessary because the production account does not need to access the development account KMS key.

• Question 169:

  A marketing company is using Amazon DocumentDB and requires that database audit logs be enabled. A Database Specialist needs to configure monitoring so that all data definition language (DDL) statements performed are visible to the Administrator. The Database Specialist has set the audit_logs parameter to enabled in the cluster parameter group.

  What should the Database Specialist do to automatically collect the database logs for the Administrator?

  A. Enable DocumentDB to export the logs to Amazon CloudWatch Logs
  B. Enable DocumentDB to export the logs to AWS CloudTrail
  C. Enable DocumentDB Events to export the logs to Amazon CloudWatch Logs
  D. Configure an AWS Lambda function to download the logs using the download-db-log- file-portion operation and store the logs in Amazon S3
  C. Enable DocumentDB Events to export the logs to Amazon CloudWatch Logs

  ---

  Explanation/Reference:

  https://docs.aws.amazon.com/documentdb/latest/developerguide/event-auditing.html Auditing Amazon DocumentDB Events PDF Kindle RSS With Amazon DocumentDB (with MongoDB compatibility), you can audit events that were performed in your cluster. Examples of logged events include successful and failed authentication attempts, dropping a collection in a database, or creating an index. By default, auditing is disabled on Amazon DocumentDB and requires that you opt in to use this feature.

  When auditing is enabled, Amazon DocumentDB records Data Definition Language (DDL), authentication, authorization, and user management events to Amazon CloudWatch Logs. When auditing is enabled, Amazon DocumentDB exports your cluster's auditing records (JSON documents) to Amazon CloudWatch Logs. You can use Amazon CloudWatch Logs to analyze, monitor, and archive your Amazon DocumentDB auditing events.

• Question 170:

  A company is using an Amazon Aurora PostgreSQL DB cluster for the backend of its mobile application. The application is running continuously and a database specialist is satisfied with high availability and fast failover, but is concerned about performance degradation after failover.

  How can the database specialist minimize the performance degradation after failover?

  A. Enable cluster cache management for the Aurora DB cluster and set the promotion priority for the writer DB instance and replica to tier-0
  B. Enable cluster cache management tor the Aurora DB cluster and set the promotion priority for the writer DB instance and replica to tier-1
  C. Enable Query Plan Management for the Aurora DB cluster and perform a manual plan capture
  D. Enable Query Plan Management for the Aurora DB cluster and force the query optimizer to use the desired plan
  A. Enable cluster cache management for the Aurora DB cluster and set the promotion priority for the writer DB instance and replica to tier-0

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  Explanation/Reference:

  Correct Answer: A from Amazon documents: Amazon Aurora PostgreSQL supports cluster cache management, which is a feature that helps reduce the impact of failover on query performance by preserving the cache of the primary DB instance on one or more Aurora Replicas. Cluster cache management allows you to assign a promotion priority tier to each DB instance in your Aurora DB cluster. The promotion priority tier determines the order in which Aurora Replicas are considered for promotion to the primary instance after a failover. The lower the numerical value of the tier, the higher the priority. By enabling cluster cache management for the Aurora DB cluster and setting the promotion priority for the writer DB instance and replica to tier-0, the database specialist can minimize the performance degradation after failover. This solution will ensure that the primary DB instance and one Aurora Replica have the same cache contents and are in the same promotion priority tier. In the event of a failover, Aurora will promote the tier-0 replica to the primary role, and the cache will be preserved. This will reduce the number of cache misses and improve query performance after failover. Therefore, option A is the correct solution to minimize the performance degradation after failover. Option B is incorrect because setting the promotion priority for the writer DB instance and replica to tier-1 will not preserve the cache after failover. Aurora will first try to promote a tier-0 replica, which may have a different cache than the primary instance. Option C is incorrect because enabling Query Plan Management and performing a manual plan capture will not affect the cache behavior after failover. Query Plan Management is a feature that helps you control query execution plans and improve query performance by creating and enforcing custom execution plans. Option D is incorrect because enabling Query Plan Management and forcing the query optimizer to use the desired plan will not affect the cache behavior after failover. Forcing the query optimizer to use a desired plan may improve query performance by avoiding suboptimal plans, but it will not prevent cache misses after failover.