Release : 10.7.0
Component : APM Agents
Downstream traces collection can be restricted by various clamps depending on the situation and the trace type
There are general clamps which affect all trace types
On the Enterprise Manager there is an input queue clamp
If this is exceeded all other traces in that interval are dropped by the EM - you can see if this is happening by enabling DEBUG logging and looking for a message like
9/04/20 09:57:56.754 AM EDT [DEBUG] [PO:WatchedAgentPO Mailman 4] [Manager.Agent] Clamp Hit For totalMaxTTEvents Per Interval . Hence exclude Traces beyond the limit.
This is a per EM clamp
The other clamp is on the agent and again relates to the number of traces per interval
In addition there are other clamps that deal with downstream traces specifically. Smart Instrumentation has Cross Process Auto Tracing which has various sustainability metrics to monitor the feature and properties to control this feature, including several clamp properties(shown with default values):
Number of transactions a downstream agent caches for automatic cross-process trace collection.
Clamps the number of automatic traces collected by Introscope per 1 minute interval.
Max GUID cache downstream (currently hardcoded to 50)
Clamps the number of traces sent from downstream agent. The value of this clamp limit is calculated as: introscope.agent.deep.automatic.trace.clamp * introcosope.agent.deep.automatic.trace.crossprocess.downstream.clamp.multiplier