Prometheus Metrics mqtt_publish_received < mqtt_publish_sent

[René Moser]

Hi

We are running 1.12.3 for evaluation when we noticed that the values of two metrics doesn't make sense to us:

mqtt_publish_received is much lower (5-8 times) then mqtt_publish_sent.

isn't mqtt_publish_received the input and mqtt_publish_sent the output? If so, how can the input be lower then the output?

also the messages into and out of the queue differs as well. But no drops and errors? See graphs attached.

What did we miss?

Thanks for clarification.

Regards

René

[André Fatton]

Hi René

Thanks. Note that the publish_received counter will still be increased when you send a message to a topic (routing key) that has no subscriber. The message will then be dropped at the broker, and the publish_sent counter not increased.

(if you feel that does not explain what you are doing, let me know).

Alternatively, you could look at the queue_in and queue_out counters. Those are actually increased when a message enters and leaves a queue (ie, there's an actual subscriber owning the queue).

"sudo vmq-admin metrics show | grep queue".

I hope this helps,

Cheers,

André