Prometheus histogram bucket metric ends in _bucket (#3018)

open-telemetry · Jan 20, 2023 · df03f5e · df03f5e
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diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -21,6 +21,9 @@ release.
 
 ### Compatibility
 
+- Fix Prometheus histogram metric suffixes. Bucket series end in `_bucket`
+  ([#3018](https://github.com/open-telemetry/opentelemetry-specification/pull/3018)).
+
 ### OpenTelemetry Protocol
 
 ### SDK Configuration

diff --git a/specification/compatibility/prometheus_and_openmetrics.md b/specification/compatibility/prometheus_and_openmetrics.md
@@ -90,7 +90,7 @@ A [Prometheus Histogram](https://github.com/OpenObservability/OpenMetrics/blob/m
 
 Multiple Prometheus histogram metrics MUST be merged together into a single OTLP Histogram:
 
-* The `le` label on non-suffixed metrics is used to identify and order histogram bucket boundaries. Each Prometheus line produces one bucket count on the resulting histogram. Each value for the `le` label except `+Inf` produces one bucket boundary.
+* The `le` label on the `_bucket`-suffixed metric is used to identify and order histogram bucket boundaries. Each Prometheus line produces one bucket count on the resulting histogram. Each value for the `le` label except `+Inf` produces one bucket boundary.
 * Lines with `_count` and `_sum` suffixes are used to determine the histogram's count and sum.
 * If `_count` is not present, the metric MUST be dropped.
 * If `_sum` is not present, the histogram's sum MUST be unset.
@@ -275,7 +275,7 @@ An [OpenTelemetry Histogram](../metrics/data-model.md#histogram) with a cumulati
 
 - A single `{name}_count` metric denoting the count field of the histogram. All attributes of the histogram point are converted to Prometheus labels.
 - `{name}_sum` metric denoting the sum field of the histogram, reported only if the sum is positive and monotonic. The sum is positive and monotonic when all buckets are positive. All attributes of the histogram point are converted to Prometheus labels.
-- A series of `{name}` metric points that contain all attributes of the histogram point recorded as labels.  Additionally, a label, denoted as `le` is added denoting the bucket boundary. The label's value is the stringified floating point value of bucket boundaries, ordered from lowest to highest. The value of each point is the sum of the count of all histogram buckets up the the boundary reported in the `le` label. These points will include a single exemplar that falls within `le` label and no other `le` labelled point.  The final bucket metric MUST have an `+Inf` threshold.
+- A series of `{name}_bucket` metric points that contain all attributes of the histogram point recorded as labels.  Additionally, a label, denoted as `le` is added denoting the bucket boundary. The label's value is the stringified floating point value of bucket boundaries, ordered from lowest to highest. The value of each point is the sum of the count of all histogram buckets up the the boundary reported in the `le` label. These points will include a single exemplar that falls within `le` label and no other `le` labelled point.  The final bucket metric MUST have an `+Inf` threshold.
 - Histograms with `StartTimeUnixNano` set should export the `{name}_created` metric as well.
 
 OpenTelemetry Histograms with Delta aggregation temporality SHOULD be aggregated into a Cumulative aggregation temporality and follow the logic above, or MUST be dropped.