[exporter/elasticsearch] Profiling: Duplicate events if count > 1

Author: rockdaboot

.chloggen/elasticsearchexporter-profiling-duplicate-events.yaml

@@ -0,0 +1,27 @@
+# Use this changelog template to create an entry for release notes.
+
+# One of 'breaking', 'deprecation', 'new_component', 'enhancement', 'bug_fix'
+change_type: enhancement
+
+# The name of the component, or a single word describing the area of concern, (e.g. filelogreceiver)
+component: elasticsearchexporter
+
+# A brief description of the change.  Surround your text with quotes ("") if it needs to start with a backtick (`).
+note: Profiling: Duplicate events with count > 1
+
+# Mandatory: One or more tracking issues related to the change. You can use the PR number here if no issue exists.
+issues: [40946]
+
+# (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: Having all events with count=1 enables random sampling on the read path.
+
+# If your change doesn't affect end users or the exported elements of any package,
+# you should instead start your pull request title with [chore] or use the "Skip Changelog" label.
+# Optional: The change log or logs in which this entry should be included.
+# e.g. '[user]' or '[user, api]'
+# Include 'user' if the change is relevant to end users.
+# Include 'api' if there is a change to a library API.
+# Default: '[user]'
+change_logs: [user]

exporter/elasticsearchexporter/internal/serializer/otelserializer/serializeprofiles/transform.go

@@ -133,12 +133,11 @@ func stackPayloads(dic pprofile.ProfilesDictionary, resource pcommon.Resource, s
 			t := sample.TimestampsUnixNano().At(j)
 			event.TimeStamp = newUnixTime64(t)
 
+			count := 1
 			if j < sample.Value().Len() {
-				event.Count = uint16(sample.Value().At(j))
-			} else {
-				event.Count = 1 // restore default
+				count = int(sample.Value().At(j))
 			}
-			if event.Count > 0 {
+			for range count {
 				stackPayload = append(stackPayload, StackPayload{
 					StackTraceEvent: event,
 				})
@@ -214,7 +213,7 @@ func stackTraceEvent(dic pprofile.ProfilesDictionary, traceID string, sample ppr
 		EcsVersion:   EcsVersion{V: EcsVersionString},
 		HostID:       hostMetadata[string(semconv.HostIDKey)],
 		StackTraceID: traceID,
-		Count:        1, // TODO: Check whether count can be dropped with nanosecond timestamps
+		Count:        1, // Elasticsearch v9.2+ doesn't read the count value any more.
 	}
 
 	// Store event-specific attributes.

exporter/elasticsearchexporter/internal/serializer/otelserializer/serializeprofiles/transform_test.go

@@ -503,7 +503,15 @@ func TestStackPayloads(t *testing.T) {
 						EcsVersion:   EcsVersion{V: EcsVersionString},
 						TimeStamp:    1000000000,
 						StackTraceID: wantedTraceID,
-						Count:        2,
+						Count:        1,
+					},
+				},
+				{
+					StackTraceEvent: StackTraceEvent{
+						EcsVersion:   EcsVersion{V: EcsVersionString},
+						TimeStamp:    1000000000,
+						StackTraceID: wantedTraceID,
+						Count:        1,
 					},
 				},
 			},