amazon AWS Certified Database - Specialty online exam

Question 1

An Amazon RDS EBS-optimized instance with Provisioned IOPS (PIOPS) storage is using less than half of its allocated
IOPS over the course of several hours under constant load. The RDS instance exhibits multi-second read and write latency,
and uses all of its maximum bandwidth for read throughput, yet the instance uses less than half of its CPU and RAM
resources. What should a Database Specialist do in this situation to increase performance and return latency to sub-second
levels?

• A. Increase the size of the DB instance storage
• B. Change the underlying EBS storage type to General Purpose SSD (gp2)
• C. Disable EBS optimization on the DB instance
• D. Change the DB instance to an instance class with a higher maximum bandwidth

Answer:

B

Question 2

An ecommerce company is migrating its core application database to Amazon Aurora MySQL. The company is currently
performing online transaction processing (OLTP) stress testing with concurrent database sessions. During the first round of
tests, a database specialist noticed slow performance for some specific write operations.
Reviewing Amazon CloudWatch metrics for the Aurora DB cluster showed 90% CPU utilization.
Which steps should the database specialist take to MOST effectively identify the root cause of high CPU utilization and slow
performance? (Choose two.)

• A. Enable Enhanced Monitoring at less than 30 seconds of granularity to review the operating system metrics before the next round of tests.
• B. Review the VolumeBytesUsed metric in CloudWatch to see if there is a spike in write I/O.
• C. Review Amazon RDS Performance Insights to identify the top SQL statements and wait events.
• D. Review Amazon RDS API calls in AWS CloudTrail to identify long-running queries.
• E. Enable Advance Auditing to log QUERY events in Amazon CloudWatch before the next round of tests.

Answer:

B C

Explanation:
Reference: https://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/USER_PerfInsights.API.html

Question 3

A media company wants to use zero-downtime patching (ZDP) for its Amazon Aurora MySQL database. Multiple processing
applications are using SSL certificates to connect to database endpoints and the read replicas.
Which factor will have the LEAST impact on the success of ZDP?

• A. Binary logging is enabled, or binary log replication is in progress.
• B. Current SSL connections are open to the database.
• C. Temporary tables or table locks are in use.
• D. The value of the lower_case_table_names server parameter was set to 0 when the tables were created.

Answer:

A

Explanation:
Aurora MySQL 2.10 and higher, Aurora can perform a zero-downtime patch when binary log replication is enabled.
Reference: https://docs.aws.amazon.com/AmazonRDS/latest/AuroraUserGuide/AuroraMySQL.Updates.Patching.html

Question 4

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?

• A. Add an allow statement for the dynamodb:PutItem action in a policy attached to the role used by the application creating the table.
• B. Set the StreamEnabled property of the StreamSpecification parameter to true, then call PutItem.
• C. Change the application to call DescribeTable periodically until the TableStatus is ACTIVE, then call PutItem.
• D. Add a ConditionExpression parameter in the PutItem request.

Answer:

D

Explanation:
Reference: https://docs.aws.amazon.com/amazondynamodb/latest/APIReference/API_PutItem.html

Question 5

A company is running a two-tier ecommerce application in one AWS account. The web server is deployed using an Amazon
RDS for MySQL Multi-AZ DB instance. A Developer mistakenly deleted the database in the production environment. The
database has been restored, but this resulted in hours of downtime and lost revenue.
Which combination of changes in existing IAM policies should a Database Specialist make to prevent an error like this from
happening in the future? (Choose three.)

• A. Grant least privilege to groups, users, and roles
• B. Allow all users to restore a database from a backup that will reduce the overall downtime to restore the database
• C. Enable multi-factor authentication for sensitive operations to access sensitive resources and API operations
• D. Use policy conditions to restrict access to selective IP addresses
• E. Use AccessList Controls policy type to restrict users for database instance deletion
• F. Enable AWS CloudTrail logging and Enhanced Monitoring

Answer:

A C D

Question 6

A companys ecommerce website uses Amazon DynamoDB for purchase orders. Each order is made up of a Customer ID
and an Order ID. The DynamoDB table uses the Customer ID as the partition key and the Order ID as the sort key.
To meet a new requirement, the company also wants the ability to query the table by using a third attribute named Invoice
ID. Queries using the Invoice ID must be strongly consistent. A database specialist must provide this capability with optimal
performance and minimal overhead.
What should the database administrator do to meet these requirements?

• A. Add a global secondary index on Invoice ID to the existing table.
• B. Add a local secondary index on Invoice ID to the existing table.
• C. Recreate the table by using the latest snapshot while adding a local secondary index on Invoice ID.
• D. Use the partition key and a FilterExpression parameter with a filter on Invoice ID for all queries.

Answer:

C

Question 7

A Database Specialist is troubleshooting an application connection failure on an Amazon Aurora DB cluster with multiple
Aurora Replicas that had been running with no issues for the past 2 months. The connection failure lasted for 5 minutes and
corrected itself after that. The Database Specialist reviewed the Amazon RDS events and determined a failover event
occurred at that time. The failover process took around 15 seconds to complete.
What is the MOST likely cause of the 5-minute connection outage?

• A. After a database crash, Aurora needed to replay the redo log from the last database checkpoint
• B. The client-side application is caching the DNS data and its TTL is set too high
• C. After failover, the Aurora DB cluster needs time to warm up before accepting client connections
• D. There were no active Aurora Replicas in the Aurora DB cluster

Answer:

C

Question 8

A company has an Amazon RDS Multi-AZ DB instances that is 200 GB in size with an RPO of 6 hours. To meet the
companys disaster recovery policies, the database backup needs to be copied into another Region. The company requires
the solution to be cost-effective and operationally efficient.
What should a Database Specialist do to copy the database backup into a different Region?

• A. Use Amazon RDS automated snapshots and use AWS Lambda to copy the snapshot into another Region
• B. Use Amazon RDS automated snapshots every 6 hours and use Amazon S3 cross-Region replication to copy the snapshot into another Region
• C. Create an AWS Lambda function to take an Amazon RDS snapshot every 6 hours and use a second Lambda function to copy the snapshot into another Region
• D. Create a cross-Region read replica for Amazon RDS in another Region and take an automated snapshot of the read replica

Answer:

D

Explanation:
Reference: https://aws.amazon.com/blogs/database/implementing-a-disaster-recovery-strategy-with-amazon-rds/

Question 9

A company is using a Single-AZ Amazon RDS for MySQL DB instance for development. The DB instance is experiencing
slow performance when queries run. Amazon CloudWatch metrics indicate that the instance requires more I/O capacity.
Which actions can a database specialist perform to resolve this issue? (Choose two.)

• A. Restart the application tool used to run queries.
• B. Change to a database instance class with higher throughput.
• C. Convert from Single-AZ to Multi-AZ.
• D. Increase the I/O parameter in Amazon RDS Enhanced Monitoring.
• E. Convert from General Purpose to Provisioned IOPS (PIOPS).

Answer:

B D

Question 10

A manufacturing companys website uses an Amazon Aurora PostgreSQL DB cluster.
Which configurations will result in the LEAST application downtime during a failover? (Choose three.)

• A. Use the provided read and write Aurora endpoints to establish a connection to the Aurora DB cluster.
• B. Create an Amazon CloudWatch alert triggering a restore in another Availability Zone when the primary Aurora DB cluster is unreachable.
• C. Edit and enable Aurora DB cluster cache management in parameter groups.
• D. Set TCP keepalive parameters to a high value.
• E. Set JDBC connection string timeout variables to a low value.
• F. Set Java DNS caching timeouts to a high value.

Answer:

A B C