Exam AWS Certified Developer - Associate DVA-C02 topic 1 question 97 discussion

A. Refactor the Lambda function into two functions. Configure one function to transform the data and one function to load the data into the DynamoDB table. Create an Amazon Simple Queue Service (Amazon SQS) queue in between the functions to hold the items as messages and to invoke the second function. By breaking the Lambda function into two separate functions and using an SQS queue to hold the transformed data as messages, you can decouple the data transformation and loading processes. This allows for more controlled loading of data into the DynamoDB table and helps eliminate throttling issues.

This solution will allow the developer to store the incoming data into the DynamoDB table more consistently without being throttled. By splitting the Lambda function into two functions, the first function can store the data into the DynamoDB table and exit quickly, avoiding any throttling issues. The second function can then process the data and update the items after the data is stored in DynamoDB using a DynamoDB stream to invoke the second function. Option A is also a good option but not the best solution because it introduces additional complexity and cost by using an Amazon SQS queue.

Adjusting the WCU is enough. no need to implement such complex solutions

The SQS queue acts as a buffer, which smooths out sudden traffic spikes by queuing up data. The second Lambda function processes data from the queue at a steady rate, reducing the likelihood of throttling in DynamoDB. B) Eliminated - Auto scaling takes time to adjust, during which throttling may still occur. C) Eliminated - Provisioned concurrency ensures that the Lambda function can handle a predictable number of concurrent requests, but it does not solve the throttling issue at the DynamoDB layer

It's hands-down A.

"A" would be optimal, but without backoff algorithm the lambda division and SQS won't affect the throttling. However Dynamo can autoscale https://docs.aws.amazon.com/amazondynamodb/latest/developerguide/AutoScaling.html

A is the correct answer.

we are trying to stop throttling...

This solution addresses the need to eliminate throttling and ensure consistent data loading into the Amazon DynamoDB table by separating the transformation and loading processes into two different functions. Using an Amazon SQS queue to hold items as messages between the two functions helps manage the flow of data and prevents overloading the DynamoDB table, thereby eliminating throttling issues.

A is correct as it requires to write to DynamoDB "more consistently". Option B can solve the problem too but the writing won't be consistent as the traffic will go up and down instantly. In reality, I will probably do Option B only.

I do not feel refactoring the data transformation and loading would help here as I do not think the number of concurrent calls to the DB would decrease because of this. Autoscaling DynamoDB would seem a more potent option to me.

Why not B ? DynamoDB can autoscale the RCU and WCU

A. Refactor the Lambda function into two functions, using an Amazon SQS queue to manage the data flow, and/or B. Turn on auto scaling for the DynamoDB table to automatically adjust its write capacity based on traffic patterns. Both A and B address the core issue of managing write throughput to the DynamoDB table to prevent throttling. Option A provides a way to smooth out data flow and manage write requests more effectively, while option B allows the table to scale its capacity automatically in response to changing traffic, although with potential limitations in response speed to sudden traffic spikes. Combining these approaches could provide an even more robust solution.

Off course A & D are options but here after inserting the data further we cannot modify because one extra writing cost will incur rather using queue lambda can poll the transformed data

Answer : A SQS can be configured to invoke Lambda. https://docs.aws.amazon.com/AWSSimpleQueueService/latest/SQSDeveloperGuide/sqs-configure-lambda-function-trigger.html

I think B

Lambda functions can be triggered by SQS: https://docs.aws.amazon.com/AWSSimpleQueueService/latest/SQSDeveloperGuide/sqs-configure-lambda-function-trigger.html