Clarify cardinality capping should be after filtering (#4228)

open-telemetry · Sep 27, 2024 · 0e78770 · 0e78770
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diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -22,6 +22,8 @@ release.
  ([#4211](https://github.com/open-telemetry/opentelemetry-specification/pull/4211))
 - Make all fields as identifying for Meter. Previously attributes were omitted from being identifying.
  ([#4161](https://github.com/open-telemetry/opentelemetry-specification/pull/4161))
+- Clarify that applying cardinality limits should be done after attribute filtering.
+ ([#4228](https://github.com/open-telemetry/opentelemetry-specification/pull/4228))
 
 ### Logs
 

diff --git a/specification/metrics/sdk.md b/specification/metrics/sdk.md
@@ -780,7 +780,9 @@ SDKs SHOULD support being configured with a cardinality limit. The number of
 unique combinations of attributes is called cardinality. For a given metric, the
 cardinality limit is a hard limit on the number of [Metric
 Points](./data-model.md#metric-points) that can be collected during a collection
-cycle.
+cycle. Cardinality limit enforcement SHOULD occur _after_ attribute filtering,
+if any. This ensures users can filter undesired attributes using [views](#view)
+and prevent reaching the cardinality limit.
 
 #### Configuration