CODEWITHSUNDEEP
javamessage-queueamazon-sqs
user3198603
user3198603

Reputation: 5816

How Amazon SQS works in this scenario?

Consumer is listening on queue(FIFO or standard queue ),Producer produces the message on queue.

  1. Does Amazon SQS queue deletes the message from queue automatically once it gets acknowledgement from consumer ? Is there a way/configuration where queue keeps the message instead of deleting it and ensures it is not delivered again.

  2. Producer produces the message on queue. Consumer becomes offline because of network issue. After some time he/she get backs to online. will queue deliver the message to consumer when he gets online ? I think yes as queue has not received ACK from consumer.

Upvotes: 1

Views: 387

Answers (1)

inquisitive
inquisitive

Reputation: 3629

I believe you are asking from rabbitmq perspective. There is some difference. There is no ack in sqs. Messages are not automatically deleted, they stay in queue even after a consumer accepts it. The messages need to be explictly deleted by the consumer after it has done processing it.

Sqs does not bother about the online offline status of a consumer. The consumer periodically polls sqs for new items. If a message is available, it is handed out. Once consumer is done, it calls sqs to delete that message. Then again poll for new message.

In your scenario, once the consumer is done processing a message, it can make two requests: one to enqueue the message in a different queue and second to delete the message from original queue.

If you have multiple consumers listning on the same queue, then a concept of message-invisibility-period comes to play. If you have such setup, ask in comments and i will update with more info.

Hope it helps.

Upvotes: 1

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