Which solution will meet these requirements?
Decrease the batch window to 1 second when configuring the Lambda function’s event source mapping.
Decrease the batch size to 1 when configuring the Lambda function’s event source mapping.
Include the ReportBatchItemFailures value in the FunctionResponseTypes list in the Lambda function’s event source mapping.
Set the queue visibility timeout on the Lambda function’s event source mapping to account for invocation throttling of the Lambda function.
Explanations:
Decreasing the batch window to 1 second does not directly prevent duplicate processing of messages. It only controls how quickly messages can be processed after they become available, which may increase invocation frequency but doesn’t affect message visibility or processing state.
Decreasing the batch size to 1 will limit the number of messages processed in a single Lambda invocation, but it does not inherently prevent duplicate processing of messages. If a message fails processing, it could still be retried multiple times if not handled properly.
Including the ReportBatchItemFailures value in the FunctionResponseTypes allows the Lambda function to report which specific messages failed processing. This prevents the entire batch from being retried when only some messages fail, thus ensuring that successfully processed messages are not reprocessed, enhancing scalability and ensuring message integrity.
Setting the queue visibility timeout to account for invocation throttling is important for ensuring messages aren’t processed before Lambda has a chance to complete its execution. However, it does not directly address preventing duplicate processing of successfully processed messages, as it focuses more on managing the visibility timeout rather than tracking message success.
I organize that the answer is:
Include the ReportBatchItemFailures value in the FunctionResponseTypes list in the Lambda function’s event source mapping.