The metrics transfer design document looks good to me. Thanks for your work Chesnay :-)
I think the benefit of registering the metrics at the MetricDumper is that we don't have to walk through the hierarchy of metric groups to collect the metric values. Indeed, this comes with increased costs at start-up. But I'm not sure what's the concrete impact on job performance in these cases. Cheers, Till On Tue, Aug 2, 2016 at 8:34 PM, Stephan Ewen <se...@apache.org> wrote: > Hi! > > Thanks for writing this up. I think it looks quite reasonable (I hope I > understood that design correctly) > > There is one point of confusions left for me, though: The MetricDumper and > MetricSnapshot: I think it is just the names that confuse me here. > It looks like they define a way to query the metrics in the Metric Registry > in a standard schema (independent of the scope formats). > Should the "dumper" maybe be called "MetricsQueryService" or so (the query > service returns a MetricSnapshot, if I understand correctly). > > It would be great if the "query service" would not need metrics to be > registered - saves us some effort during startup / teardown. It looks > as if the query service could just use the the root-most component metric > groups to walk the tree of whatever metric is currently there and put it > into the current snapshot. > > One open questions that I have is: How do you know how to merge the metrics > from the subtasks, for example in case you want a metric across subtasks. > > In general, not transferring objects (only strings / numbers) would be > preferable, because the WebMonitor may run in an environment where no > user-code classloader can be used. > It may run in the dispatcher (which must be trusted and cannot execute user > code). > > Greetings, > Stephan > > > > On Thu, Jul 28, 2016 at 3:12 PM, Chesnay Schepler <ches...@apache.org> > wrote: > > > Hello, > > > > I just created a new FLIP which aims at exposing our metrics to the > > WebInterface. > > > > > > > https://cwiki.apache.org/confluence/display/FLINK/FLIP-7%3A+Expose+metrics+to+WebInterface > > > > Looking forward to feedback :) > > > > Regards, > > Chesnay Schepler > > >
