Question

A developer is building an order-processing service that consumes messages from Amazon SQS. Each customer's orders must be processed strictly in the order they were submitted, but orders from different customers can be processed in parallel to maximize throughput. Which approach meets these requirements with the least custom code?

Accepted Answer

Use an SQS FIFO queue and set the MessageGroupId to the customer ID when sending each message.

Answer

Use an SQS standard queue and store a sequence number in each message; have the consumer reorder messages before processing.

Answer

Use an SQS FIFO queue and set the same MessageGroupId for all messages regardless of customer.

Answer

Use an SQS standard queue with a visibility timeout long enough to guarantee sequential delivery.