You are building an online store on AWS that uses SQS to process your customer orders. Your backend system
needs those messages in the same sequence the customer orders have been put in. How can you achieve
that?
A.
It is not possible to do this with SQS
B.
You can use sequencing information on each message
C.
You can do this with SQS but you also need to use SWF
D.
Messages will arrive in the same order by default
Explanation:
Amazon SQS is engineered to always be available and deliver messages. One of the resulting tradeoffs is that
SQSdoes not guarantee first in, first out delivery of messages. For many distributed applications, each message
can stand on its own, and as long as all messages are delivered, the order is not important. If your system
requires that order be preserved, you can place sequencing information in each message, so that you can
reorder the messages when the queue returns them.
What if I want the messages to be delivered in order?
Amazon SQS makes a best effort to preserve order in messages, but due to the distributed nature of the queue, we cannot guarantee that you will receive messages in the exact order you sent them. You typically place sequencing information or timestamps in your messages so that you can reorder them upon receipt.
B.
You can use sequencing information on each message
https://aws.amazon.com/articles/Amazon-SQS/1343#03
B
http://docs.aws.amazon.com/AWSSimpleQueueService/latest/SQSDeveloperGuide/standard-queues.html
Message Ordering
A standard queue makes a best effort to preserve the order of messages, but more than one copy of a message might be delivered out of order. If your system requires that order be preserved, we recommend either using a FIFO (First-In-First-Out) queue or adding sequencing information in each message so you can reorder the messages when they’re received.
B
Amazon SQS makes a best effort to preserve order in messages, but due to the distributed nature of the queue, we cannot guarantee that you will receive messages in the exact order you sent them. You typically place sequencing information or timestamps in your messages so that you can reorder them upon receipt.
B but now u can send messages in queue with SQS.
B
B.
You can use sequencing information on each message