A company is using an Amazon Aurora PostgreSQL DB cluster with an xlarge primary instance master and two large Aurora Replicas for high availability and read-only workload scaling. A failover event occurs and application performance is poor for several minutes. During this time, application servers in all Availability Zones are healthy and responding normally.
What should the company do to eliminate this application performance issue?

1. A. Configure both of the Aurora Replicas to the same instance class as the primary DB instanc
2. B. Enable cache coherence on the DB cluster, set the primary DB instance failover priority to tier-0, and assign a failover priority of tier-1 to the replicas.
3. C. Deploy an AWS Lambda function that calls the DescribeDBInstances action to establish which instance has failed, and then use the PromoteReadReplica operation to promote one Aurora Replica to be the primary DB instanc
4. D. Configure an Amazon RDS event subscription to send a notification to an Amazon SNS topic to which the Lambda function is subscribed.
5. E. Configure one Aurora Replica to have the same instance class as the primary DB instanc
6. F. Implement Aurora PostgreSQL DB cluster cache managemen
7. G. Set the failover priority to tier-0 for the primary DB instance and one replica with the same instance clas
8. H. Set the failover priority to tier-1 for the other replicas.
9. I. Configure both Aurora Replicas to have the same instance class as the primary DB instanc
10. J. Implement Aurora PostgreSQL DB cluster cache managemen
11. K. Set the failover priority to tier-0 for the primary DB instance and to tier-1 for the replicas.

Correct Answer: C
https://docs.aws.amazon.com/AmazonRDS/latest/AuroraUserGuide/AuroraPostgreSQL.cluster-cache-mgmt.htm https://aws.amazon.com/blogs/database/introduction-to-aurora-postgresql-cluster-cache-management/
"You can customize the order in which your Aurora Replicas are promoted to the primary instance after a failure by assigning each replica a priority. Priorities range from 0 for the first priority to 15 for the last priority. If the primary instance fails, Amazon RDS promotes the Aurora Replica with the better priority to the new primary instance. You can modify the priority of an Aurora Replica at any time. Modifying the priority doesn't trigger a failover. More than one Aurora Replica can share the same priority, resulting in promotion tiers. If two or more Aurora Replicas share the same priority, then Amazon RDS promotes the replica that is largest in size. If two or more Aurora Replicas share the same priority and size, then Amazon RDS promotes an arbitrary replica in the same promotion tier. "
Amazon Aurora with PostgreSQL compatibility now supports cluster cache management, providing a faster path to full performance if there's a failover. With cluster cache management, you designate a specific reader DB instance in your Aurora PostgreSQL cluster as the failover target. Cluster cache management keeps the data in the designated reader's cache synchronized with the data in the read-write instance's cache. If a failover occurs, the designated reader is promoted to be the new read-write instance, and workloads benefit immediately from the data in its cache.

A company hosts a 2 TB Oracle database in its on-premises data center. A database specialist is migrating the database from on premises to an Amazon Aurora PostgreSQL database on AWS.
The database specialist identifies a problem that relates to compatibility Oracle stores metadata in its data dictionary in uppercase, but PostgreSQL stores the metadata in lowercase. The database specialist must resolve this problem to complete the migration.
What is the MOST operationally efficient solution that meets these requirements?

1. A. Override the default uppercase format of Oracle schema by encasing object names in quotation marks during creation.
2. B. Use AWS Database Migration Service (AWS DMS) mapping rules with rule-action as convert-lowercase.
3. C. Use the AWS Schema Conversion Tool conversion agent to convert the metadata from uppercase to lowercase.
4. D. Use an AWS Glue job that is attached to an AWS Database Migration Service (AWS DMS) replication task to convert the metadata from uppercase to lowercase.

Correct Answer: B
https://aws.amazon.com/premiumsupport/knowledge-center/dms-mapping-oracle-postgresql/

A business's production databases are housed on a 3 TB Amazon Aurora MySQL DB cluster. The database cluster is installed in the region us-east-1. For disaster recovery (DR) requirements, the company's database expert needs to fast deploy the DB cluster in another AWS Region to handle the production load with an RTO of less than two hours.
Which approach is the MOST OPERATIONALLY EFFECTIVE in meeting these requirements?

1. A. Implement an AWS Lambda function to take a snapshot of the production DB cluster every 2 hours, and copy that snapshot to an Amazon S3 bucket in the DR Regio
2. B. Restore the snapshot to an appropriately sized DB cluster in the DR Region.
3. C. Add a cross-Region read replica in the DR Region with the same instance type as the current primary instanc
4. D. If the read replica in the DR Region needs to be used for production, promote the read replica to become a standalone DB cluster.
5. E. Create a smaller DB cluster in the DR Regio
6. F. Configure an AWS Database Migration Service (AWS DMS) task with change data capture (CDC) enabled to replicate data from the current production DB cluster to the DB cluster in the DR Region.
7. G. Create an Aurora global database that spans two Region
8. H. Use AWS Database Migration Service (AWS DMS) to migrate the existing database to the new global database.

Correct Answer: B
RTO is 2 hours. With 3 TB database, cross-region replica is a better option

A company is going to use an Amazon Aurora PostgreSQL DB cluster for an application backend. The DB cluster contains some tables with sensitive data. A Database Specialist needs to control the access privileges at the table level.
How can the Database Specialist meet these requirements?

1. A. Use AWS IAM database authentication and restrict access to the tables using an IAM policy.
2. B. Configure the rules in a NACL to restrict outbound traffic from the Aurora DB cluster.
3. C. Execute GRANT and REVOKE commands that restrict access to the tables containing sensitive data.
4. D. Define access privileges to the tables containing sensitive data in the pg_hba.conf file.

Correct Answer: C

An ecommerce company is using Amazon DynamoDB as the backend for its order-processing application.
The steady increase in the number of orders is resulting in increased DynamoDB costs. Order verification and reporting perform many repeated GetItem functions that pull similar datasets, and this read activity is contributing to the increased costs. The company wants to control these costs without significant development efforts.
How should a Database Specialist address these requirements?

1. A. Use AWS DMS to migrate data from DynamoDB to Amazon DocumentDB
2. B. Use Amazon DynamoDB Streams and Amazon Kinesis Data Firehose to push the data into Amazon Redshift
3. C. Use an Amazon ElastiCache for Redis in front of DynamoDB to boost read performance
4. D. Use DynamoDB Accelerator to offload the reads

Correct Answer: D
https://docs.amazonaws.cn/en_us/amazondynamodb/latest/developerguide/DAX.html
"Applications that are read-intensive, but are also cost-sensitive. With DynamoDB, you provision the number of reads per second that your application requires. If read activity increases, you can increase your tables' provisioned read throughput (at an additional cost). Or, you can offload the activity from your application to a DAX cluster, and reduce the number of read capacity units that you need to purchase otherwise."