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

Because the Lambda function is successfully triggered by the S3 event notification, the invocation path (S3 → Lambda) is working correctly. The failure occurs specifically when the function tries to write to DynamoDB, which strongly indicates an authorization problem rather than an invocation, scaling, or infrastructure issue.

In AWS, a Lambda function interacts with other services by using its execution role (an IAM role). AWS documentation explains that a Lambda function must have explicit IAM permissions to call downstream services such as DynamoDB. To write items, the role typically needs actions like dynamodb:PutItem (and sometimes dynamodb:UpdateItem, dynamodb:BatchWriteItem, depending on code behavior) on the target table resource ARN. If these permissions are missing or scoped incorrectly, DynamoDB returns an AccessDeniedException (or similar) and the function fails at the write step.

Option A is unlikely because exceeding concurrency would typically prevent invocation or cause throttling at the Lambda service level, not selectively fail only at DynamoDB write time after the function begins executing.

Option B is incorrect: DynamoDB does not require a GSI to support writes. GSIs are for alternate query access patterns, not mandatory for write operations.

Option D is incorrect because DynamoDB is a regional service, not tied to a single Availability Zone, and Lambda does not need to be “in the same AZ” to access it.

Therefore, the most likely cause is that the Lambda execution role lacks the necessary IAM permissions to perform DynamoDB write operations.

Amazon ElastiCache is a service that offers fully managed in-memory data stores that are compatible with Redis or Memcached. The developer can create an ElastiCache for Redis instance and enable encryption of data in transit and at rest. This will ensure that the PHI is encrypted at all times. The developer can store frequently accessed data in the cache and use Redis features such as sorting and ranking to enhance the performance of the application.

Amazon S3 event notifications can invoke AWS Lambda functions at very high rates during traffic spikes. In this scenario, up to 500 objects per minute can result in hundreds of concurrent Lambda invocations. By default, Lambda functions share the account’s unreserved concurrency pool, which can cause throttling if the pool is exhausted by sudden bursts.

AWS Lambda reserved concurrency guarantees a specific number of concurrent executions for a function. By configuring reserved concurrency, the developer ensures that sufficient execution capacity is always available for this specific function, regardless of other Lambda workloads in the account. This prevents throttling during high-volume S3 event bursts.

Increasing the timeout (Option A) does not address concurrency limits. Adding a layer (Option B) does not solve invocation throttling. Decreasing memory (Option D) can actually worsen performance and increase execution time.

AWS documentation explicitly recommends reserved concurrency when workloads experience unpredictable or bursty invocation patterns and must run reliably. Therefore, reserving concurrency is the correct and AWS-recommended solution.