What message processing guarantees are provided by the VM queue and the CloudHub workers, and how are VM messages routed among the CloudHub workers for each invocation of the parent flow under normal operating conditions where all the CloudHub workers remain online?

Refer to the exhibit.

A Mule 4 application has a parent flow that breaks up a JSON array payload into 200 separate items, then sends each item one at a time inside an Async scope to a VM queue.

A second flow to process orders has a VM Listener on the same VM queue. The rest of this flow processes each received item by writing the item to a database.

This Mule application is deployed to four CloudHub workers with persistent queues enabled.

What message processing guarantees are provided by the VM queue and the CloudHub workers, and how are VM messages routed among the CloudHub workers for each invocation of the parent flow under normal operating conditions where all the CloudHub workers remain online?
A . EACH item VM message is processed AT MOST ONCE by ONE CloudHub worker, with workers chosen in a deterministic round-robin fashion Each of the four CloudHub workers can be expected to process 1/4 of the Item VM messages (about 50 items)
B . EACH item VM message is processed AT LEAST ONCE by ONE ARBITRARY CloudHub worker Each of the four CloudHub workers can be expected to process some item VM messages
C . ALL Item VM messages are processed AT LEAST ONCE by the SAME CloudHub worker where the parent flow was invoked
This one CloudHub worker processes ALL 200 item VM messages
D . ALL item VM messages are processed AT MOST ONCE by ONE ARBITRARY CloudHub worker This one CloudHub worker processes ALL 200 item VM messages

View Answer

Answer: B

Explanation:

Correct answer is EACH item VM message is processed AT LEAST ONCE by ONE ARBITRARY CloudHub worker. Each of the four CloudHub workers can be expected to process some item VM messages In Cloudhub, each persistent VM queue is listened on by every CloudHub worker – But each message is read and processed at least once by only one CloudHub worker and the duplicate processing is possible – If the CloudHub worker fails, the message can be read by another worker to prevent loss of messages and this can lead to duplicate processing – By default, every CloudHub worker’s VM Listener receives different messages from VM Queue Referenece: https://dzone.com/articles/deploying-mulesoft-application-on-1-worker-vs-mult