How to count active requests? about metrics HOT 3 CLOSED

You'll need to track the number of requests separately.

from metrics.

I thought it over and I think that my use case is quite common – there are more things to count with increments and decrements, which are not counted separately. Also, Java Metrics has inc() and dec() in Counter – probably because they are useful. I think that adding AddN() or Inc() to Gauge will be okay. Will you accept a good pull request?

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I think you'd be better off using two counters—one for requests and one for responses. This gives you the ability to plot a cumulative flow diagram of your service, from which you can determine not just the queue size—the number of active requests—but also the queue delay, the arrival rate, and the departure rate. These parameters allow for robust modeling of your service via Little's Law.

The main problem with the Java library is that I wrote it to work with the dumbest aggregation layer around, Ganglia. Ganglia just takes data and puts it in an RRD. At the time you couldn't effectively combine data streams, so I wrote Metrics as essentially a graphing engine—to produce the various data streams that I wanted graphed in order to know what my services were doing at runtime. This library is intended to be something different.

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