I’m troubleshooting missing spans in OpenTelemetry traces

Got it — “missing spans” in OpenTelemetry usually comes down to one of a few areas: instrumentation, context propagation, sampling, batching/export, or backend-side filtering.

Here’s a practical troubleshooting checklist:

1) Confirm the spans are actually being created

• Enable debug logging for your SDK / auto-instrumentation.
• Look for span start/end events or exporter logs.
• If you create spans manually, verify the code path is reached.

2) Check context propagation

Missing child spans often mean the trace context isn’t flowing correctly.

• Verify propagation across:
  • HTTP headers
  • gRPC metadata
  • async tasks / thread pools
  • message queues
• Common issues:
  • context lost in new threads
  • forgetting to inject/extract headers
  • using incompatible propagators

3) Inspect sampling

The spans may exist but be dropped by sampling.

• Check:
  • parent-based vs always-on sampling
  • head sampling rate
  • tail sampling policies in collector/backend
• If the root span is sampled out, children won’t appear.

4) Verify the exporter and collector

• Ensure the SDK exporter can reach the collector/backend.
• Check collector logs for:
  • dropped spans
  • queue overflows
  • timeouts
  • auth errors
• Confirm the endpoint, protocol, and port are correct (OTLP gRPC vs HTTP).

5) Look for batch/flush issues

Spans may be created but never exported if the process exits too quickly.

• Use a batch span processor with flush/shutdown handling.
• In short-lived jobs/functions:
  • force flush before exit
  • wait for exporter completion

6) Check span limits / truncation

Some spans can be dropped or reduced due to limits:

• attribute count limits
• event/link limits
• max span size in backend
• name/attribute filtering

7) Compare expected vs actual topology

Sometimes spans aren’t missing — they’re in a different trace due to broken propagation.

• Search by service name, operation name, or trace ID if available.
• Look for multiple root spans where you expected one trace.

8) Validate instrumentation order

For auto-instrumentation:

• make sure it initializes before libraries are loaded/used
• check whether a framework version is supported
• confirm no conflicting instrumentation packages

If you want, I can help you debug this systematically. Tell me:

1. language/runtime
2. SDK or auto-instrumentation you’re using
3. exporter/collector/backend
4. whether the missing spans are parent/child spans or entire traces
5. any relevant logs or config snippets

And I can narrow it down quickly.