Replace otel.sdk.span.ended metric with improved span.started metric

.chloggen/span-ended-metric-improvements.yaml

@@ -0,0 +1,22 @@
+# Use this changelog template to create an entry for release notes.
+#
+# If your change doesn't affect end users you should instead start
+# your pull request title with [chore] or use the "Skip Changelog" label.
+
+# One of 'breaking', 'deprecation', 'new_component', 'enhancement', 'bug_fix'
+change_type: 'enhancement'
+
+# The name of the area of concern in the attributes-registry, (e.g. http, cloud, db)
+component: 'otel'
+
+# A brief description of the change. Surround your text with quotes ("") if it needs to start with a backtick (`).
+note: Ensure that the `otel.sdk.span.ended` is collected even for non-recording spans and allow differentiation based on the parent span origin
+
+# Mandatory: One or more tracking issues related to the change. You can use the PR number here if no issue exists.
+# The values here must be integers.
+issues: [2431]
+
+# (Optional) One or more lines of additional information to render under the primary note.
+# These lines will be padded with 2 spaces and then inserted directly into the document.
+# Use pipe (|) for multiline entries.
+subtext:

docs/otel/sdk-metrics.md

@@ -54,7 +54,8 @@ This metric is [recommended][MetricRecommended].
 | `otel.sdk.span.live` | UpDownCounter | `{span}` | The number of created spans for which the end operation has not been called yet [1] | ![Development](https://img.shields.io/badge/-development-blue) |  |
 
 **[1]:** For spans with `recording=true`: Implementations MUST record both `otel.sdk.span.live` and `otel.sdk.span.ended`.
-For spans with `recording=false`: If implementations decide to record this metric, they MUST also record `otel.sdk.span.ended`.
+For spans with `recording=false`: Implementations MAY omit recording `otel.sdk.span.live` (e.g. for performance or simplicity reasons).
+In that case they MUST record `otel.sdk.span.ended` on span start for those spans instead.
 
 | Attribute  | Type | Description  | Examples  | [Requirement Level](https://opentelemetry.io/docs/specs/semconv/general/attribute-requirement-level/) | Stability |
 |---|---|---|---|---|---|
@@ -91,14 +92,27 @@ This metric is [recommended][MetricRecommended].
 | `otel.sdk.span.ended` | Counter | `{span}` | The number of created spans for which the end operation was called [1] | ![Development](https://img.shields.io/badge/-development-blue) |  |
 
 **[1]:** For spans with `recording=true`: Implementations MUST record both `otel.sdk.span.live` and `otel.sdk.span.ended`.
-For spans with `recording=false`: If implementations decide to record this metric, they MUST also record `otel.sdk.span.live`.
+For spans with `recording=false`: If implementations decide to not record `otel.sdk.span.live`, they MUST record `otel.sdk.span.ended` on span start for those spans instead.
+In other words, for spans with `recording=false` implementations may treat them as ended directly after they are started from a metrics perspective.
+This ensures that `otel.sdk.span.ended` is guaranteed to provide insights about the total span counts and sampling rates, even if spans are not recorded.
 
 | Attribute  | Type | Description  | Examples  | [Requirement Level](https://opentelemetry.io/docs/specs/semconv/general/attribute-requirement-level/) | Stability |
 |---|---|---|---|---|---|
+| [`otel.span.parent.origin`](/docs/registry/attributes/otel.md) | string | Determines whether the span has a parent span, and if so, whether it is a remote parent | `NONE`; `LOCAL`; `REMOTE` | `Recommended` | ![Development](https://img.shields.io/badge/-development-blue) |
 | [`otel.span.sampling_result`](/docs/registry/attributes/otel.md) | string | The result value of the sampler for this span | `DROP`; `RECORD_ONLY`; `RECORD_AND_SAMPLE` | `Recommended` | ![Development](https://img.shields.io/badge/-development-blue) |
 
 ---
 
+`otel.span.parent.origin` has the following list of well-known values. If one of them applies, then the respective value MUST be used; otherwise, a custom value MAY be used.
+
+| Value  | Description | Stability |
+|---|---|---|
+| `LOCAL` | The span has a parent and the parent's span context isRemote() is false | ![Development](https://img.shields.io/badge/-development-blue) |
+| `NONE` | The span does not have a parent, it is a root span | ![Development](https://img.shields.io/badge/-development-blue) |
+| `REMOTE` | The span has a parent and the parent's span context isRemote() is true | ![Development](https://img.shields.io/badge/-development-blue) |
+
+---
+
 `otel.span.sampling_result` has the following list of well-known values. If one of them applies, then the respective value MUST be used; otherwise, a custom value MAY be used.
 
 | Value  | Description | Stability |

docs/registry/attributes/otel.md

@@ -14,12 +14,23 @@ Attributes reserved for OpenTelemetry
 
 | Attribute | Type | Description | Examples | Stability |
 |---|---|---|---|---|
+| <a id="otel-span-parent-origin" href="#otel-span-parent-origin">`otel.span.parent.origin`</a> | string | Determines whether the span has a parent span, and if so, whether it is a remote parent | `NONE`; `LOCAL`; `REMOTE` | ![Development](https://img.shields.io/badge/-development-blue) |
 | <a id="otel-span-sampling-result" href="#otel-span-sampling-result">`otel.span.sampling_result`</a> | string | The result value of the sampler for this span | `DROP`; `RECORD_ONLY`; `RECORD_AND_SAMPLE` | ![Development](https://img.shields.io/badge/-development-blue) |
 | <a id="otel-status-code" href="#otel-status-code">`otel.status_code`</a> | string | Name of the code, either "OK" or "ERROR". MUST NOT be set if the status code is UNSET. | `OK`; `ERROR` | ![Stable](https://img.shields.io/badge/-stable-lightgreen) |
 | <a id="otel-status-description" href="#otel-status-description">`otel.status_description`</a> | string | Description of the Status if it has a value, otherwise not set. | `resource not found` | ![Stable](https://img.shields.io/badge/-stable-lightgreen) |
 
 ---
 
+`otel.span.parent.origin` has the following list of well-known values. If one of them applies, then the respective value MUST be used; otherwise, a custom value MAY be used.
+
+| Value  | Description | Stability |
+|---|---|---|
+| `LOCAL` | The span has a parent and the parent's span context isRemote() is false | ![Development](https://img.shields.io/badge/-development-blue) |
+| `NONE` | The span does not have a parent, it is a root span | ![Development](https://img.shields.io/badge/-development-blue) |
+| `REMOTE` | The span has a parent and the parent's span context isRemote() is true | ![Development](https://img.shields.io/badge/-development-blue) |
+
+---
+
 `otel.span.sampling_result` has the following list of well-known values. If one of them applies, then the respective value MUST be used; otherwise, a custom value MAY be used.
 
 | Value  | Description | Stability |

model/otel/metrics.yaml

@@ -8,7 +8,8 @@ groups:
     unit: "{span}"
     note: |
       For spans with `recording=true`: Implementations MUST record both `otel.sdk.span.live` and `otel.sdk.span.ended`.
-      For spans with `recording=false`: If implementations decide to record this metric, they MUST also record `otel.sdk.span.ended`.
+      For spans with `recording=false`: Implementations MAY omit recording `otel.sdk.span.live` (e.g. for performance or simplicity reasons).
+      In that case they MUST record `otel.sdk.span.ended` on span start for those spans instead.
     attributes:
       - ref: otel.span.sampling_result
 
@@ -21,9 +22,12 @@ groups:
     unit: "{span}"
     note: |
       For spans with `recording=true`: Implementations MUST record both `otel.sdk.span.live` and `otel.sdk.span.ended`.
-      For spans with `recording=false`: If implementations decide to record this metric, they MUST also record `otel.sdk.span.live`.
+      For spans with `recording=false`: If implementations decide to not record `otel.sdk.span.live`, they MUST record `otel.sdk.span.ended` on span start for those spans instead.
+      In other words, for spans with `recording=false` implementations may treat them as ended directly after they are started from a metrics perspective.
+      This ensures that `otel.sdk.span.ended` is guaranteed to provide insights about the total span counts and sampling rates, even if spans are not recorded.
     attributes:
       - ref: otel.span.sampling_result
+      - ref: otel.span.parent.origin
 
   - id: metric.otel.sdk.processor.span.queue.size
     type: metric

model/otel/registry.yaml

@@ -39,6 +39,23 @@ groups:
               stability: development
         brief: "The result value of the sampler for this span"
         stability: development
+      - id: otel.span.parent.origin
+        type:
+          members:
+            - id: none
+              value: NONE
+              brief: 'The span does not have a parent, it is a root span'
+              stability: development
+            - id: local
+              value: LOCAL
+              brief: The span has a parent and the parent's span context isRemote() is false
+              stability: development
+            - id: remote
+              value: REMOTE
+              brief: The span has a parent and the parent's span context isRemote() is true
+              stability: development
+        brief: "Determines whether the span has a parent span, and if so, whether it is a remote parent"
+        stability: development
   - id: registry.otel.scope
     type: attribute_group
     display_name: OTel Scope Attributes