Your company has a logging microservice used to generate logs when users have entered certain commands in another application. This logging service is implemented via an SQS standard queue that an EC2 instance is listening to. However, you have found that on some occasions, the order of the logs is not maintained. As a result, it becomes harder to use this service to trace users’ activities. How should you simply fix this issue?

Answer options:

A.Convert the existing standard queue into a FIFO queue. Add a deduplication ID for the messages that are sent to the queue.
B.Delete the existing standard queue and recreate it as a FIFO queue. As a result, the order for the messages to be received is ensured.
C.Migrate the whole microservice application to SWF so that the operation sequence is guaranteed.
D.The wrong order of timestamps is a limitation of SQS, which does not have a fix.

Correct Answer – B
The FIFO queue improves upon and complements the standard queue. The most important features of this queue type are FIFO (First-In-First-Out) delivery and exactly-once processing. The FIFO queue is mainly used to process the messages in the queue that needs to be guaranteed without any items being out of order or duplicated.
Option A is incorrect: Because you can`t convert an existing standard queue into a FIFO queue. This is clarified in
https://docs.aws.amazon.com/AWSSimpleQueueService/latest/SQSDeveloperGuide/FIFO-queues.html.
Option B is CORRECT: Because the FIFO queue can guarantee the sequence for users’ operations so that the issue of the logging system is fixed.
Option C is incorrect: Because this is not a straightforward method by changing the whole microservice to SWF. Option B is much simpler than this option.
Option D is incorrect: Refer to the explanations in Option
B.