Sampling - Lumina Documentation

Reduce overhead by sampling a subset of traces.

Head-Based Sampling

Sample at trace start:

const lumina = initLumina({
  endpoint: 'http://localhost:9411/v1/traces',
  service_name: 'high-volume-service',
  samplingRate: 0.1, // Sample 10%
});

Conditional Sampling

Always sample important traces:

const lumina = initLumina({
  endpoint: 'http://localhost:9411/v1/traces',
  service_name: 'service',
  samplingRate: 0.1,
  alwaysSampleConditions: {
    error: true,              // Always sample errors
    costUsd: { $gt: 0.5 },   // Always sample expensive calls
  },
});

When to Use Sampling

> 100K traces/day — Consider 10-20% sampling
> 1M traces/day — Use 1-5% sampling
Production — Balance cost vs visibility

Impact

10% sampling:

90% reduction in storage costs
90% reduction in ingestion load
May miss rare errors

Conditional sampling:

Sample routine operations at low rate
Capture all errors at 100%
Best of both worlds