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Documentation Index

Fetch the complete documentation index at: https://docs.odigos.io/llms.txt

Use this file to discover all available pages before exploring further.

Highly Relevant rules mark traces you want to treat as important, aligned with RED-style signals (request, error, duration). They are the second stage in the rule evaluation pipeline, evaluated only on traces that did not match any Noisy rule.

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How they’re evaluated

  • Tail-aware. Importance often depends on something that only appears mid-trace—an error on a child span, or a long downstream call—so the evaluator typically needs the assembled trace. See Head vs. tail sampling.
  • One error span marks the entire trace. When a Highly Relevant error rule applies, a single error span anywhere in the tree is enough to classify the whole trace as important.
  • 100% retention by default. Highly Relevant rules keep every matching trace by default—as the built-in error rule does—which works for most workloads. If a specific operation produces too much volume, lower its Keep Percentage on a custom rule to retain only a fractional sample, while still benefiting from Highly Relevant priority.

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Built-in rule: Keep All Error Traces

Odigos ships a single built-in Highly Relevant rule, Keep All Error Traces, which retains 100% of traces that contain at least one span with error status. The built-in rule’s keep percentage is fixed at 100% and is not configurable. Because the evaluator inspects every span in the trace, a single error anywhere in the call tree is enough to keep the whole trace—even when the root span itself succeeds.
If 100% retention of error traces is more than you need—for example because your error volume is high—author your own Highly Relevant rule on errors with the Keep Percentage you want. Custom rules are how you express any intent other than the built-in 100%.

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Interaction with Cost Reduction

When a trace matches rules in both Highly Relevant and Cost Reduction, the Highly Relevant Keep Percentage always wins, whether higher or lower than the Cost Reduction cap. See Evaluation between Highly Relevant and Cost Reduction for worked examples.
Highly Relevant rules without any Cost Reduction rules do not aggressively reduce volume on their own. Unimportant traffic still flows through the gateway and may be evaluated as part of full-trace policy. Pair Highly Relevant with Cost Reduction when you need both signal and volume control.

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Typical use cases

  • Keep all (or most) traces with at least one error span
  • Keep a higher percentage of traces over a duration threshold (for example > 500 ms)
  • Always keep a sample from a critical service or route