Standard queues let you have nearly an unlimited number of transactions per second. Standard queues guarantee that a message is delivered at least once. They also provide best-effort ordering which ensures that messages are gradually delivered in the same order as they are received.
items are pushed to queue in order, but applications polling or receiving records might get them not in the exact order ( Best-Effort Ordering) and occasionally a copy of the message could be delivered ( At-Least-Once delivery )