Configure tail sampling in the OpenTelemetry Collector to keep only high-value traces

Steps

1. Add the tailsampling processor to your Collector pipeline in the processors section of the config
2. Set decision_wait (e.g., 10s) to control how long the Collector buffers spans before making a sampling decision; ensure this is longer than your slowest service's trace duration
3. Define policies in the tail_sampling processor: combine latency (threshold_ms), status_code (ERROR), probabilistic (sampling_percentage), and composite policies using the and policy type
4. Route all OTLP receivers through the tailsampling processor before the exporter so that span data is held in memory during the decision window
5. In a multi-Collector deployment use the loadbalancing exporter in a gateway tier to route all spans of a given trace_id to the same Collector instance running tail sampling
6. Monitor Collector memory usage; set memory_limiter processor before tailsampling to emit a backpressure signal and drop data before OOM