Amazon Web Services DVA-C02 Exam With Confidence Using Practice Dumps

The correct answer is D because the current DynamoDB table design is causing a hot partition problem. The table uses order_date as the partition key, which means that during peak ordering periods, a very large number of writes are likely targeting the same partition key value for the current date. In DynamoDB, write throttling often occurs when traffic is not evenly distributed across partition keys, even when the table uses on-demand mode . On-demand capacity can automatically scale, but it still depends on proper key distribution to avoid concentrated activity on a small number of partitions.

By changing the partition key to customer_id and using order_id as the sort key, writes will be spread across many customers instead of being concentrated on a small number of date values. This creates a more balanced write pattern and better aligns with DynamoDB best practices for high-scale workloads. DynamoDB documentation emphasizes choosing partition keys with high cardinality and even request distribution to avoid throttling and improve performance.

Option A is not a good design because a sequential partition key can still create uneven access patterns and usually does not support meaningful access requirements. Option B is not the best answer because simply increasing capacity does not fix a poor partition key design; hot partitions can still throttle. Option C is unnecessary because the issue is not that DynamoDB is the wrong service, but that the table schema needs redesign.

Therefore, the best solution is to refactor the key schema so that writes distribute more evenly across partitions, which is exactly what D achieves.

IAM Roles for EC2 (A): The most secure way to provide AWS permissions from EC2.

Create a role with a policy allowing s3:GetObject on the specific bucket.

Attach the role to an instance profile and associate that profile with your instances.

Pre-signed URLs (C): Temporary, authenticated URLs for specific S3 actions.

Modify the app to use the AWS SDK to call GeneratePresignedUrl.

Embed these URLs when a user is properly logged in, allowing download access.

Requirement Summary:

Store customer orders in DynamoDB

Must encrypt data at rest

Company wants to use a key it generates (i.e., customer managed key)

Evaluate Options:

A. Set encryption to None, manually encrypt/decrypt in code

Overhead and error-prone

Also non-compliant with AWS encryption best practices

B. Use customer managed KMS key

Exactly meets the requirement: customer generates and controls the key

During table creation, you can specify a KMS CMK ARN

C. Default encryption + kms:Encrypt in SDK

Misunderstanding: DynamoDB handles encryption automatically

You don’t need to call kms:Encrypt manually in SDK

D. Use AWS managed key

Does not meet the requirement of using custom company-generated key

DynamoDB encryption:

KMS customer managed keys: