What are the assumptions and limitations for the derived metric calculation in AppDynamics Extensions?
Contents
Assumptions
The assumptions made before the derived metrics calculation is initiated are:
- All the base metrics (in all different levels) are available (i.e, the metrics have been reported) for derived metrics calculation.
- For a derived metric to be calculated, all of its base metrics should have reported a valid Number.
Limitations
The limitation when using the derived metrics calculator is:
A derived metric cannot be reused in another derived metric
If a derived metric has to be calculated at different levels, each metric has to be specified separately in the list of metrics under the derivedMetrics section. For example, in the following metric tree:
Server1
Queue
Queue1
RAM ops : 9
Hdd ops: 3
Total ops:12
Queue2
Total ops : 2
Hdd ops: 6
Total ops:8
Total ops: (12 + 8 = 20)
If the "Total ops" metric is required both at the queue level and server level, then the derivedMetrics section looks as follows:
- derivedMetricPath: “{x}|Queue|{y}|Total ops" //queue level Total ops
formula: “{x}|Queue|{y}|RAM ops + {x}|Queue|{y}|Total ops”
- derivedMetricPath: “{x}|Total ops" //server level Total ops
formula: “{x}|Queue|{y}|RAM ops + {x}|Queue|{y}|Total ops”
The queue level “Total ops” derived metric cannot be used for calculating the server level or any other level derived metric.
