diff --git a/docs/specs/om/open_metrics_spec_2_0.md b/docs/specs/om/open_metrics_spec_2_0.md index ec10d36fd..549a5bca4 100644 --- a/docs/specs/om/open_metrics_spec_2_0.md +++ b/docs/specs/om/open_metrics_spec_2_0.md @@ -128,7 +128,7 @@ Each MetricPoint consists of a set of values, depending on the MetricFamily type Exemplars are references to data outside of the MetricSet. A common use case are IDs of program traces. -Exemplars MUST consist of a LabelSet and a value, and MUST have a timestamp. They MAY each be different from the MetricPoints' LabelSet and timestamp. +Exemplars MUST consist of a LabelSet and a value, and MUST have a timestamp. The LabelSet SHOULD NOT contain any Label names included in the MetricPoint's LabelSet. The timestamp SHOULD NOT be after the MetricPoint's timestamp, if present, and SHOULD NOT be before the MetricPoint's start timestamp, if present. The Exemplar's timestamp SHOULD be close to the point in time when the referenced data was created, but doesn't have to be exact. For example if getting an exact timestamp is costly, it is acceptable to use some external source or synthetic clock.