Single Span Sampling

[ygree]

What Does This Do

Implementation of the single span sampling mechanism described in this RFC.

It introduces SpanProcessingWorker running in its own thread that is responsible for sampling single spans. It receives unsampled traces from PrioritizationStrategy and then sampled spans are sent to TraceProcessingWorker for serialization and transporting to the Agent.

graph TD

PS[PrioritizationStrategy]
pQ[primaryQueue]
sQ[secondaryQueue]
TPW[TraceProcessingWorker]
subgraph  
  ssQ[spanQueue]
  SPW[SpanProcessingWorker]
  or{Is Single Span Sampling enabled?}
end

PS--sampled traces-->pQ
PS--unsampled traces-->or
or--yes-->ssQ
or--no-->sQ

pQ--consumed by-->TPW
sQ--consumed by-->TPW

ssQ--->SPW
SPW--sampled spans-->pQ
SPW--unsampled spans*-->sQ

Motivation

This is a replacement for existing Analytics events that have been deprecated for a long time.

Additional Notes