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APM - need explanantion of concurrent invocations metric as the documentation does not explain min, max and count

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Article ID: 213229

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Updated On:

Products

DX Application Performance Management CA Application Performance Management (APM / Wily / Introscope) CA Application Performance Management Agent (APM / Wily / Introscope) CA Application Performance Management SaaS

Issue/Introduction

The blamepoint metric documentation for concurrent invocations states  () 

"CA APM calculates the Concurrent Invocations metric by counting the number of requests which were still being handled at the end of a particular interval."

"Concurrent invocations start during an interval without finishing during the same interval." 

It goes on to show an illustration with min 0 max 2 and value 1 with a count of 6 - and explains that it shows 1 request was still being handled at the end of the interval - so I don't follow the meaning / relevance of min max and count - if is it is just the number of requests still executing surely min max and value should be the same and count should be 1 ?

 

Environment

Release : 10.7.0, 20.x

Component : APM Agents

Resolution

The meanings of the individual values are as follows

min = 0: there was a point in time during the interval where there was no transaction in flight for this component (entered but not exited)
Max = 2: there was a point in time during the interval where there were 2 transactions in flight
value = 1: at the end of interval there was 1 transaction in flight
Count = 6: 6 times during the interval the component was either entered or exited by a transaction and therefore a new value of the metric recorded

Every time a transaction enters the method the Concurrent Invocations metric is increased by one (and the count), every time a transaction exits the method the Concurrent Invocations metric is decreased by one (and the count increased)


The responses per interval metric for the component will be roughly equal to the concurrent invocation count / 2