Subscription count metrics is always returning 0

[jayeshkm]

Subscribing to topic $SYS/broker/subscriptions/count always returns subscription count as 0 even though there are valid subscriptions

[halfgaar]

You're right, it should be fixed. I had to disable it at some point because counting it accurately was causing too much load. At least with that implementation. It needs refactor.

[jayeshkm]

I have not went in depth into the code, but I see subscriptionCount variable in subscription store. Can we just return that?

[halfgaar]

No, it's more complicated. It has to do with how sessions are added to the subscription tree as weak pointers. They will expire sooner or later, but this can't easily be tracked.

I may make the subscription counter indicative instead of 100% correct. It can be recalculated upon certain internal maintenance jobs, but that means that the count will be (a bit) higher than factually correct.