RabbitMQ queues remain in a "running" state even when there are no consumers connected

[Sameer-Italiya]

Community Support Policy

• I have read RabbitMQ's Community Support Policy

RabbitMQ version used

4.0.3

How is RabbitMQ deployed?

Debian package

Steps to reproduce the behavior in question

I have upgraded rabbitmq to version 4.0.5 in ubuntu 22.04 after that in all the queues, state are showing running even if consumers count is zero

[michaelklishin]

@Sameer-Italiya they are "running" because they emit stats and that counts for recent activity. The stats are collected every 5 seconds by default but you can increase this interval (15s-30s sounds reasonable to me).

That's also the default management UI update frequency.

[Sameer-Italiya]

@michaelklishin This is the by default feature the came up with RabbitMQ version 4? If Yes then can we have any release note or documentation where these thing mention like consumers are always in running state in queue unless there is some issue

[mkuratczyk]

Ok, so classic queues. And what about my other question?

I don't think there was a deliberate change in this area. RabbitMQ 4.0 only uses classic queues v2, perhaps while moving everything towards v2, something was missed and they don't hibernate or perhaps they hibernate but that's not reflected in the Management UI. I can take a look, but I'm still interested why you care. What do you conclude from the queue being idle?

[Sameer-Italiya]

@mkuratczyk There is no flow in a queue for producer and consumer and also no message in a queue. Still queue state is running and that is concern have. If there is no flow in queue then state should be in idle state but in my RabbitMQ 4.0.5 queue state is always is running state either flow is there or not

[mkuratczyk]

You still haven't answered my question, you just repeat that it should work exactly as it used to.
I'm pretty sure your understanding of the queue states doesn't match what they actually mean.

[Sameer-Italiya]

@mkuratczyk I didn't catch up your question. Can you please repeat once

[mkuratczyk]

I'm asking for the "why" - why do you care if the queue is displayed as idle or not? What do you think this means? What do you conclude from that state? You said you are "concerned" about it not being idle, but why? The queue works fine, so what is the problem?

I had a quick look and indeed, it seems like the queue is never displayed as idle right now (seems like it wasn't in 3.13 either). So there's something to investigate and perhaps fix. But I'd still like to know how users use this information. As I mentioned, other queue types have never been displayed as idle and I don't recall anyone asking for it.

[Sameer-Italiya]

If queue is showing idle which means there is no messages that can be produce and consume and from that it assumes no activity is there and if the queue is not in idle state that means it's running state then there should some message produce and consume activity is running.

Now in my case if queue state will always in running state then we will never predict that in a queue message activity is running or its idle

[Sameer-Italiya]

For RabbitMQ version 4 also queue is in hibernates or queue has nothing to do but still state is showing as running

[mkuratczyk]

As I said - I can take a look at what changed in 4.0 (or perhaps earlier). I don't think there was a deliberate change around idleness/hibernation, so it could be that we accidentally changed/missed something. But the idle state never meant what you thought it meant, so you should probably look at other metrics instead.

[michaelklishin]

@Sameer-Italiya every queue, in 3.x or 4.x, emits metrics every 5 seconds, which counts for activity.

[Sameer-Italiya]

@michaelklishin didn't catch you. Please provide in-depth detail

[michaelklishin]

@Sameer-Italiya I don't know what can I possibly add to the fact that queue replicas emit metrics every five seconds, which counts activity and will change the queue's state to "running".

[Sameer-Italiya]

If queue is hibernate then in version 4 also state should be idle but it's in running state only all the time

[Sameer-Italiya]

Agree that I have wrong perception for this concepts but please check as per the screenshot and let me know once check from your end

[michaelklishin]

This is going in circles. If @mkuratczyk wants to take a closer look, I have no objections, otherwise this is just a waste of everyone's time.

The entire metric arguably should be removed and replaced with another one that says whether the queue has an elected leader (for QQs and streams). That's the biggest benefit of this metric, which with default settings will be reported as running, if anything, because of its periodic stats emission.

Using this state for monitoring has never been a good idea except for spotting any queues without an elected leader. For which we should soon enough have a dedicated health check.