Topic: AWS Certified DevOps Engineer - Professional DOP-C02 topic 1 question 168

A DevOps engineer is building a solution that uses Amazon Simple Queue Service (Amazon SQS) standard queues. The solution also includes an AWS Lambda function and an Amazon DynamoDB table. The Lambda function pulls content from an SQS queue event source and writes the content to the DynamoDB table.

The solution must maximize the scalability of Lambda and must prevent successfully processed SQS messages from being processed multiple times.

Which solution will meet these requirements?

A.
Decrease the batch window to 1 second when configuring the Lambda function's event source mapping.
B.
Decrease the batch size to 1 when configuring the Lambda function's event source mapping.
C.
Include the ReportBatchItemFailures value in the FunctionResponseTypes list in the Lambda function's event source mapping.
D.
Set the queue visibility timeout on the Lambda function's event source mapping to account for invocation throttling of the Lambda function.

Re: AWS Certified DevOps Engineer - Professional DOP-C02 topic 1 question 168

To avoid reprocessing successfully processed messages in a failed batch, you can configure your event source mapping to make only the failed messages visible again. This is called a partial batch response. To turn on partial batch responses, specify ReportBatchItemFailures for the FunctionResponseTypes action when configuring your event source mapping. This lets your function return a partial success, which can help reduce the number of unnecessary retries on records. https://docs.aws.amazon.com/lambda/latest/dg/with-sqs.html#services-sqs-batchfailurereporting

  • dkp
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Re: AWS Certified DevOps Engineer - Professional DOP-C02 topic 1 question 168

answer C

Re: AWS Certified DevOps Engineer - Professional DOP-C02 topic 1 question 168

https://docs.aws.amazon.com/lambda/latest/dg/with-sqs.html#services-sqs-batchfailurereporting

Re: AWS Certified DevOps Engineer - Professional DOP-C02 topic 1 question 168

C is correct. We need ReportBatchItemFailures to return only failed items
A: batch window is the interval process time
B: batch size is the size of the job
D: queue visibility timeout is about re-process

Re: AWS Certified DevOps Engineer - Professional DOP-C02 topic 1 question 168

https://docs.aws.amazon.com/lambda/latest/dg/with-sqs.html#services-sqs-batchfailurereporting

Re: AWS Certified DevOps Engineer - Professional DOP-C02 topic 1 question 168

Lambda process messages in batches. If one message in the batch fails the whole batch considered failed and all messages in the batch return to the queue. For example if batch has 10 messages and message 5 and 7 failed to get processed, all 10 messages will return to the queue. So, successfully processed messages can get processed again.

Now to prevent this to happen you have two ways (used to be one)
1. Write your code in a way to identify processed messages and delete them manually from SQS.
2. Partial batch response that returns only the messages that were failed to be processed (supported since Dec 2021).

References:
https://docs.aws.amazon.com/lambda/latest/dg/with-sqs.html
https://docs.aws.amazon.com/lambda/latest/dg/with-sqs.html#services-sqs-batchfailurereporting

Re: AWS Certified DevOps Engineer - Professional DOP-C02 topic 1 question 168

C is correct.

  • csG13
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Re: AWS Certified DevOps Engineer - Professional DOP-C02 topic 1 question 168

It's C, here is a reference:

https://docs.aws.amazon.com/lambda/latest/dg/with-sqs.html#services-sqs-batchfailurereporting

Re: AWS Certified DevOps Engineer - Professional DOP-C02 topic 1 question 168

B is correct