Hi,
I'm a Computer Science PhD student working on modelling the performance of distributed stream processing systems like Storm. I am attempting to use Queueing Theory to model the performance of a running topology and then make predictions about performance under varying input loads. To do this accurately I need metrics for the latency, arrival and emission rates of each task (among other things), which Storm happily gives me. However, I know that Storm samples the summary metrics for the UI using the Config.TOPOLOGY_STATS_SAMPLE_RATE value (default to 0.05), but does this apply to the metrics on the "__metrics" stream which, as I understand it, are sent to any bolt implementing IMetricConsumer registered with Topology? Any hints would be greatly appreciated, as a last resort I can go digging in the source code but I would like to avoid that if possible. Also let me know if this would be better posted on the dev mailing list. This is my 1st time using the mailing list, I am likely to have more questions in the future and I want to avoid spamming the wrong people. Thanks in advance, Tom Cooper PhD Student Newcastle University, School of Computer Science
