fix: widen v8js.gc.duration histogram buckets#1119
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The @opentelemetry/instrumentation-runtime-node default buckets for v8js.gc.duration are [10ms, 100ms, 1s, 10s], which lumps every incremental and minor GC pause into the first bucket and provides no resolution above 1s for long major collections. Add a View on this meter to use sub-millisecond boundaries from 100µs up through 30s, so incremental/minor pauses are distinguishable and major pauses above 1s land in their own buckets.
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Pull request overview
This PR refines OpenTelemetry metric aggregation for Node.js runtime GC pause durations by adding a scoped View override for the v8js.gc.duration histogram, improving resolution for sub-millisecond pauses and long major-GC events without affecting other metrics.
Changes:
- Adds a dedicated explicit-bucket boundary set for
v8js.gc.duration. - Registers a
Viewscoped tometerName: '@opentelemetry/instrumentation-runtime-node'andinstrumentName: 'v8js.gc.duration'to apply the new buckets.
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ferhatelmas
approved these changes
May 21, 2026
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Summary
The
v8js.gc.durationhistogram emitted by@opentelemetry/instrumentation-runtime-nodeuses 4 hardcoded bucket boundaries:[10ms, 100ms, 1s, 10s]. This is one bucket per decade, which:This PR adds a
Viewon the runtime-node meter that overrides the buckets forv8js.gc.durationonly, with boundaries (in seconds):Sub-ms boundaries surface incremental/minor pauses; the 2.5s/5s/10s/30s tail keeps long major collections visible before the overflow bucket.
No other metric is affected — the override is scoped to
meterName: '@opentelemetry/instrumentation-runtime-node',instrumentName: 'v8js.gc.duration'.Test plan
npx tsc -noEmitnpm run lintnpx vitest run --config vitest.unit.config.ts src/internal/monitoring(69 tests pass)v8js_gc_duration_bucketseries in Prometheus/OTLP backend exposes the newlevalues and that incremental-kind samples populate buckets below 10ms.