Distributed Tracing — Notes

Functional

• Trace = tree of spans across services.
• Each span: (trace_id, span_id, parent_id, service, op, ts, duration, attrs).
• Query by trace ID, service, operation, time range.

Non-functional

• Ingestion: 100k+ spans/s.
• Storage at sampled rate; 1-10% typical head sampling.
• p99 trace lookup < 1 s.

Trade-offs

• Head sampling simpler; tail sampling keeps all errors + slow.
• OpenTelemetry as standard wins; proprietary SDKs declining.
• Exemplars link metrics → exact traces.

Refs

• OpenTelemetry docs; Jaeger, Tempo, Zipkin papers.
• Honeycomb / Lightstep blog series.
• Google Dapper paper (the original).