Metrics Number data points requirements for value

open-telemetry / opentelemetry-proto

OpenTelemetry protocol (OTLP) specification and Protobuf definitions

https://opentelemetry.io/docs/specs/otlp/

Apache License 2.0

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Metrics Number data points requirements for value #286

Open bogdandrutu opened 3 years ago

bogdandrutu commented 3 years ago

Define if it is an error or not to receive for the same "Resource, InstrumentationLibrary, MetricName, Labels/Attributes, StartTime" first point with int value and next point with double value.

We need to document this behavior.

RichiH commented 3 years ago

Copying from Slack to make sure it's not lost: OM considers it non-breaking, but not something that should happen frequently: https://github.com/OpenObservability/OpenMetrics/blob/main/specification/OpenMetrics.md#exposition-across-time-and-metric-evolution

jsuereth commented 3 years ago

We discussed this in the Metrics Data Model SiG.

Based on previous discussion we don't think this is blocking declaring our API sstable.
We should specify what is allowable within a collector ("on the wire"), specifically around aggregations.

We had talked about a notion of "weak conformance" that allows migrating int to double when this situation occurs. Specification remains TBD.