Hi Nikolay,
I think "idle time" is a useful metric, but it can be calculated outside of
Ignite using external monitoring system.
About execution and waiting time, it's not the right way to calculate it
using a jobs list. Will jobs list contain only active jobs? In this case,
you can't calculate these metrics at all, since you don't know the time of
finished jobs. If the list will contain all jobs (will it be unlimited?),
iterating over this list will be resource consuming. In any way, it's much
simpler (and sometimes only possible) for an external monitoring system to
just get some scalar metric than iterate over a list with some condition.
About aggregation, yes, in an ideal world aggregation should be done with
the external monitoring system. But, what if a user doesn't use any
external monitoring system and wants to know the health of Ignite instance?
Do we have any plans to implement some simple aggregator and ship it with
Ignite? Do we have plans to provide some presets for Ignite monitoring for
popular monitoring systems? (These questions not related to this PR, but
related to IEP at all)
Also, some aggregation metrics ("max" for example) can't be effectively
calculated using the external system (you should iterate over a jobs list
again and still precision of such calculation will be no more than the time
between probes).
