How should the developer resolve this issue?

Explanations:

Creating an SQS FIFO queue enables message deduplication, which prevents the same message from being processed multiple times. This is critical in preventing duplicate data from being inserted into Amazon Redshift, especially since all duplicate messages were submitted within a short time frame. FIFO queues maintain the order of messages and ensure that each message is processed only once, addressing the issue directly.

Reducing the maximum Lambda concurrency limits the number of simultaneous executions but does not address the root cause of duplicate messages being processed. This option does not provide a mechanism to prevent duplicates; it only slows down the processing rate, which could lead to delays without solving the duplication problem.

Using Lambda’s temporary storage to track processed message identifiers is a workaround that may lead to complexity and potential issues, especially if the Lambda function fails or if multiple instances of the function run concurrently. This approach is not a reliable or scalable solution for ensuring that duplicates are not processed, particularly in a distributed system like SQS.

While configuring a message group ID is a requirement for FIFO queues, enabling message deduplication on a standard SQS queue is not valid since standard queues do not support message deduplication features. This option does not effectively prevent duplicate processing, making it an unsuitable solution for the problem at hand.