[exporter/loadbalancing] Improve the performance when merging traces …

…belonging to the same backend (open-telemetry#32032) **Description:** no need to reimplement that in an extremely allocation-inefficient fashion. I'm actually not sure why mergeTraces() and mergeMetrics() need to exist in the first place; all the other exporters coupled with the batch processor work just fine, not sure why loadbalancing would be special. open-telemetry#30141 seems to imply they were implemented to improve performance, but I don't really understand why batch processor would not have been sufficient for that improvement originally. benchmarks before: ``` goos: darwin goarch: arm64 pkg: github.com/open-telemetry/opentelemetry-collector-contrib/exporter/loadbalancingexporter BenchmarkMergeTraces_X100-8 50214 23507 ns/op BenchmarkMergeTraces_X500-8 10000 113952 ns/op BenchmarkMergeTraces_X1000-8 5208 226062 ns/op BenchmarkMergeMetrics_X100-8 64933 18540 ns/op BenchmarkMergeMetrics_X500-8 12885 91418 ns/op BenchmarkMergeMetrics_X1000-8 6590 184584 ns/op PASS ok github.com/open-telemetry/opentelemetry-collector-contrib/exporter/loadbalancingexporter 9.783s ``` and after: ``` goos: darwin goarch: arm64 pkg: github.com/open-telemetry/opentelemetry-collector-contrib/exporter/loadbalancingexporter BenchmarkMergeTraces_X100-8 295886529 3.836 ns/op BenchmarkMergeTraces_X500-8 309865370 3.833 ns/op BenchmarkMergeTraces_X1000-8 310739948 3.800 ns/op BenchmarkMergeMetrics_X100-8 315567813 3.841 ns/op BenchmarkMergeMetrics_X500-8 310341650 3.849 ns/op BenchmarkMergeMetrics_X1000-8 314292003 3.830 ns/op PASS ok github.com/open-telemetry/opentelemetry-collector-contrib/exporter/loadbalancingexporter 10.733s ``` **Link to tracking Issue:** n/a **Testing:** unit tests pass & cpu time for our collectors using loadbalancingexporter (12 replicas, total of 25k-40k spans/sec) went from 800ms-1400ms/sec down to <40msec/sec. **Documentation:** none --------- Co-authored-by: Juraci Paixão Kröhling <[email protected]>
SolaceDev · May 8, 2024 · 0e2f434 · 0e2f434
1 parent f617c65
commit 0e2f434
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diff --git a/.chloggen/loadbalancingexporter_perf.yaml b/.chloggen/loadbalancingexporter_perf.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: loadbalancingexporter
+
+# A brief description of the change.  Surround your text with quotes ("") if it needs to start with a backtick (`).
+note: Improve the performance when merging traces belonging to the same backend 
+
+# Mandatory: One or more tracking issues related to the change. You can use the PR number here if no issue exists.
+issues: [32032]
+
+# (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:
+
+# 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: []
diff --git a/exporter/loadbalancingexporter/helpers.go b/exporter/loadbalancingexporter/helpers.go
@@ -10,114 +10,12 @@ import (
 
 // mergeTraces concatenates two ptrace.Traces into a single ptrace.Traces.
 func mergeTraces(t1 ptrace.Traces, t2 ptrace.Traces) ptrace.Traces {
-	mergedTraces := ptrace.NewTraces()
-
-	if t1.SpanCount() == 0 && t2.SpanCount() == 0 {
-		return mergedTraces
-	}
-
-	// Iterate over the first trace and append spans to the merged traces
-	for i := 0; i < t1.ResourceSpans().Len(); i++ {
-		rs := t1.ResourceSpans().At(i)
-		newRS := mergedTraces.ResourceSpans().AppendEmpty()
-
-		rs.Resource().MoveTo(newRS.Resource())
-		newRS.SetSchemaUrl(rs.SchemaUrl())
-
-		for j := 0; j < rs.ScopeSpans().Len(); j++ {
-			ils := rs.ScopeSpans().At(j)
-
-			newILS := newRS.ScopeSpans().AppendEmpty()
-			ils.Scope().MoveTo(newILS.Scope())
-			newILS.SetSchemaUrl(ils.SchemaUrl())
-
-			for k := 0; k < ils.Spans().Len(); k++ {
-				span := ils.Spans().At(k)
-				newSpan := newILS.Spans().AppendEmpty()
-				span.MoveTo(newSpan)
-			}
-		}
-	}
-
-	// Iterate over the second trace and append spans to the merged traces
-	for i := 0; i < t2.ResourceSpans().Len(); i++ {
-		rs := t2.ResourceSpans().At(i)
-		newRS := mergedTraces.ResourceSpans().AppendEmpty()
-
-		rs.Resource().MoveTo(newRS.Resource())
-		newRS.SetSchemaUrl(rs.SchemaUrl())
-
-		for j := 0; j < rs.ScopeSpans().Len(); j++ {
-			ils := rs.ScopeSpans().At(j)
-
-			newILS := newRS.ScopeSpans().AppendEmpty()
-			ils.Scope().MoveTo(newILS.Scope())
-			newILS.SetSchemaUrl(ils.SchemaUrl())
-
-			for k := 0; k < ils.Spans().Len(); k++ {
-				span := ils.Spans().At(k)
-				newSpan := newILS.Spans().AppendEmpty()
-				span.MoveTo(newSpan)
-			}
-		}
-	}
-
-	return mergedTraces
+	t2.ResourceSpans().MoveAndAppendTo(t1.ResourceSpans())
+	return t1
 }
 
 // mergeMetrics concatenates two pmetric.Metrics into a single pmetric.Metrics.
 func mergeMetrics(m1 pmetric.Metrics, m2 pmetric.Metrics) pmetric.Metrics {
-	mergedMetrics := pmetric.NewMetrics()
-
-	if m1.MetricCount() == 0 && m2.MetricCount() == 0 {
-		return mergedMetrics
-	}
-
-	// Iterate over the first metric and append metrics to the merged metrics
-	for i := 0; i < m1.ResourceMetrics().Len(); i++ {
-		rs := m1.ResourceMetrics().At(i)
-		newRS := mergedMetrics.ResourceMetrics().AppendEmpty()
-
-		rs.Resource().MoveTo(newRS.Resource())
-		newRS.SetSchemaUrl(rs.SchemaUrl())
-
-		for j := 0; j < rs.ScopeMetrics().Len(); j++ {
-			ils := rs.ScopeMetrics().At(j)
-
-			newILS := newRS.ScopeMetrics().AppendEmpty()
-			ils.Scope().MoveTo(newILS.Scope())
-			newILS.SetSchemaUrl(ils.SchemaUrl())
-
-			for k := 0; k < ils.Metrics().Len(); k++ {
-				metric := ils.Metrics().At(k)
-				newMetric := newILS.Metrics().AppendEmpty()
-				metric.MoveTo(newMetric)
-			}
-		}
-	}
-
-	// Iterate over the second metric and append metrics to the merged metrics
-	for i := 0; i < m2.ResourceMetrics().Len(); i++ {
-		rs := m2.ResourceMetrics().At(i)
-		newRS := mergedMetrics.ResourceMetrics().AppendEmpty()
-
-		rs.Resource().MoveTo(newRS.Resource())
-		newRS.SetSchemaUrl(rs.SchemaUrl())
-
-		for j := 0; j < rs.ScopeMetrics().Len(); j++ {
-			ils := rs.ScopeMetrics().At(j)
-
-			newILS := newRS.ScopeMetrics().AppendEmpty()
-			ils.Scope().MoveTo(newILS.Scope())
-			newILS.SetSchemaUrl(ils.SchemaUrl())
-
-			for k := 0; k < ils.Metrics().Len(); k++ {
-				metric := ils.Metrics().At(k)
-				newMetric := newILS.Metrics().AppendEmpty()
-				metric.MoveTo(newMetric)
-			}
-		}
-	}
-
-	return mergedMetrics
+	m2.ResourceMetrics().MoveAndAppendTo(m1.ResourceMetrics())
+	return m1
 }