Getting negative values for concurrent invocations metric in Introscope Investigator.
Invocations are requests handled by the application and its various parts.
Concurrent invocations are the requests being handled at a given time.
Basically, there are two methods, addConnectionPoolToken and removeConnectionPoolToken that use the SimpleIncrementor and SimpleDecrementor, respectively.
Each time the addConnectionPoolToken method is called, the metric is incremented by 1. On the other hand, when removeConnectionPoolToken is called, its metric is reduced by 1.
-1 is added to the current value.
When the application starts, the metric has a value of 0.
When the removeConnectionPoolToken is called, 0 is decremented by 1 which gives it a value of -1 and each time called thereafter decrements that number further(hence -2, -3, ...).
As long as the application is up and running the value will not be reset.
So, a value of -14 for the metric means that removeConnectionPoolToken has been called 14 times.