Bug in ros_comm: Topic Statistics rate under 0.016 Hz for some connections
There is actually no question. I just observed a strange behavior of the topic statistics feature and opened a issue on the ros github page. The issue got closed with the recommendation to ask my "question" here.
So here we go:
I have a plot-tool to visualize the statistics datas from rosbags and it seems that for some topic-connections there are only 7 messages over 420 sec on the /statistics topic, but with a pretty large amount of evaluated datas. I know that the statistics calculation uses a dynamic window if to less datas are available. But a window of 60-70 secs and more than 6000 evaluated messages seem pretty strange.This happened with more than one Topic.
There is a plot that shows this behavior here: https://github.com/ros/ros_comm/issue...
In the picture one can see the data points when a new message on /statistics with information about this specific publisher-subscriber connection was recorded. In my opinion, however, this behavior (0.016 Hz for an update on /statistics) is unintentional and unwanted. Thats why i opened a issue.
To make it clear, the expected update rate for one publisher-subscriber - connection on the statistics topic is 1 Hz (thats what my datas show for most of the other connections).
What is unexpected, the statistics data itself, or the publication rate of the /statistics topic?
The Data itself is doesn't matter. My only concern is the update rate. So for example: A topic connection with 3 Hz, sends a new message on statistics every 4 messages, so round about 1 Hz update rate. I just took a look on my data and the update rate for one connection is always about 1 Hz.