I'm not using Java Paho but PHP, Lua and C ones, but ...
> subscribed to /c
followed by that number, i.e. /c1, /c2, etc.
Is not efficient : you can remove leading '/' because it
creates an empty root tree which only implies additional processing for
no added value (well, working only on Unixes, I did the same mistake :)
> I wonder why it gets lower and lower. Is it because the
broker has more subscriptions to check to see where else to send the
message? If so, is topic to subscription matching that inefficient?
As I said, I'm not using Java, but I don't think this performance loss
is at client side. Which broker are U using and did you checked its