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In this video, we are going to talk about Amazon, create visibility, time out.

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This is the one of the important features that we should understand when we are working out on is.

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So basically when a consumer receive a process, a message from the queue, the message is remains in

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the queue.

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So Amazon case doesn't automatically delete the message because Amazon is a distributed system and there

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is no guarantee that the consumer actually receives the message.

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For example, due to a connective tissue or due to an issue in the consumer application.

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That's why the consumer must delete the message from the queue after receiving and processing it immediately

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after a message is received, it remains in the queue.

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So in order to prevent other consumers from the processing the message again, Amazon sets a visibility

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timeout, which is the period of time during which Amazon prevents other consumers from receiving and

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processing the message.

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The default visible to timeout for a message is 30 seconds and the minimum is 0 seconds.

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The maximum is 12 hours.

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We can also configuring the visibility timeout for a queue using the measurement console.

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Also, we will configure with infrastructure as code using the our SDK application.

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We will perform the set, the visible timeout both configured from the measurement console.

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And after that we will configure from the HDC application when we are creating the A queue.

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And if you look at the image on the slide, we can understand how Amazon visibility timeout is working.

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You can see in here at this point, one received message request comes from the consumer.

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You can see in here, for example, we have a consumer one and consumer one.

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Consume the message A in this point and during the time of the visible timeout message, A cannot be

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returned any other consumers in order to avoid reprocess again and again.

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So we expect that these consumer one will be processed.

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The message A And after finishing the operation where consumer one should be, delete the message from

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the queue.

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The Amazon case doesn't delete any message in the queue.

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Its expected message will be delete from the consumers then consume operation finished so during the

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visible time and no consumers can consume the message again.

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Message A In our examples because Amazon doesn't delete any message and Amazon is a distributed system

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and not interested in deleting any message.

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Expect the message should be delayed after processing from the consumers and in the visible timeout.

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The expected behavior is after consuming from the consumer.

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One the message.

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A message will be deleted from the consumer one in the queue.

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But if the consumer one is down and cannot process this message after the visible timeout, these messages

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will be reactivated in the queue.

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And once when any consumer request again this message A this will be returned from the Amazon space,

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for example.

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At this point, Consumer two can be consumed from the message again.