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Use MpscRingBuffer for CSS producer/consumer inbox - #11497

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dougqh wants to merge 169 commits into

dougqh/lazy-error-latenciesfrom

dougqh/css-ring-buffer

Commits on May 15, 2026
- Trim per-span work on metrics aggregator publish path
  
  dougqh
  and
  claude
  committed
  bc42093
- Add SpanKindFilter and CoreSpan.isKind for bitmask-based kind checks
  
  dougqh
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  claude
  committed
  808d63d
- Use SpanKindFilter in ConflatingMetricsAggregator
  
  dougqh
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  6aa620e
- Add DDSpan-based variant of ConflatingMetricsAggregator JMH benchmark
  
  dougqh
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  committed
  a02d0a9
- Tighten SpanKindFilter encapsulation
  
  dougqh
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  ed38f18
- Defer MetricKey construction and cache lookups to the aggregator thread
  
  dougqh
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  claude
  committed
  034afc0
- Report aggregator inbox-full drops via health metrics
  
  dougqh
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  3a056b3
Commits on May 18, 2026
- Merge branch 'master' into dougqh/conflating-metrics-producer-wins
  dougqh
  authored
  3355865
- Merge branch 'dougqh/conflating-metrics-producer-wins' into dougqh/conflating-metrics-background-work
  dougqh
  authored
  950499c
- Add Hashtable and LongHashingUtils to datadog.trace.util
  
  dougqh
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  claude
  committed
  0294058
- Add AggregateTable + AggregateEntry backed by Hashtable
  
  dougqh
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  claude
  committed
  f751ab4
- Swap LRUCache for AggregateTable in Aggregator + route disable() clear
  
  dougqh
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  f1b030a
- Eliminate MetricKey: inline its fields onto AggregateEntry
  
  dougqh
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  claude
  committed
  3738c85
- Add unit tests for Hashtable and LongHashingUtils
  
  dougqh
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  claude
  committed
  46a9055
- Apply spotless formatting to Hashtable and LongHashingUtils
  
  dougqh
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  claude
  committed
  031dc89
- Add JMH benchmarks for Hashtable.D1 and D2
  
  dougqh
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  claude
  committed
  f9e63b9
- Add benchmark results to HashtableBenchmark header
  
  dougqh
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  claude
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  a534e4f
Commits on May 19, 2026
- Address review feedback on Hashtable
  
  dougqh
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  claude
  committed
  ba66a36
- Fix dropped argument in HashingUtils 5-arg Object hash
  
  dougqh
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  claude
  committed
  3108941
- Address review feedback on Hashtable
  
  dougqh
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  claude
  committed
  1415f12
- Drop reflection in iterator tests via package-private D1.buckets
  
  dougqh
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  claude
  committed
  b7cee2f
- Resize previousCounts for inbox-full health metric
  
  dougqh
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  claude
  committed
  8414960
- Fold AggregateMetric into AggregateEntry
  
  dougqh
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  claude
  committed
  553ffb8
- Avoid capturing lambda in Aggregator.report
  
  dougqh
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  claude
  committed
  07ed635
- Add context-passing forEach to Hashtable.D1 and D2
  
  dougqh
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  claude
  committed
  df58ad7
- Move forEach loop body to Support helper
  
  dougqh
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  claude
  committed
  9c6e95c
- Merge branch 'dougqh/util-hashtable' into dougqh/optimize-metric-key
  dougqh
  committed
  7ab47f7
- Delegate AggregateTable.forEach to Support.forEach
  
  dougqh
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  claude
  committed
  590ab4a
- Move bucket-head cast to Support.bucket helper
  
  dougqh
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  claude
  committed
  447ea33
- Merge branch 'dougqh/util-hashtable' into dougqh/optimize-metric-key
  dougqh
  committed
  46f147a
- Use Support.bucket and type chain walks as AggregateEntry
  
  dougqh
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  claude
  committed
  dd5e13f
- Drop d1_/d2_ prefix from per-table benchmark methods
  
  dougqh
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  claude
  committed
  df7f98f
- Add Hashtable.Support helpers: MAX_RATIO, insertHeadEntry, MutatingTableIterator
  
  dougqh
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  claude
  committed
  e6ecc16
- Merge branch 'dougqh/util-hashtable' into dougqh/optimize-metric-key
  dougqh
  committed
  a409d5d
- Simplify AggregateTable via new Hashtable.Support helpers
  
  dougqh
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  claude
  committed
  96b40b8
- Swap MAX_RATIO numerator/denominator pair for a single float + scaled create()
  
  dougqh
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  claude
  committed
  55ca204
- Merge branch 'dougqh/util-hashtable' into dougqh/optimize-metric-key
  dougqh
  committed
  7b9eccd
- Address second-round review on AggregateTable / Aggregator
  
  dougqh
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  claude
  committed
  192de0c
- Tighten Hashtable docs + rename MAX_CAPACITY to MAX_BUCKETS
  
  dougqh
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  claude
  committed
  4bac439
- Dedupe chain-head splice in D1/D2 via keyHash insertHeadEntry overload
  
  dougqh
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  claude
  committed
  de289a0
- Tighten Entry.next encapsulation; doc hasNext; add D1/D2 getOrCreate
  
  dougqh
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  claude
  committed
  2dd65ed
- Merge branch 'dougqh/util-hashtable' into dougqh/optimize-metric-key
  dougqh
  committed
  cc8d98a
- Use keyHash insertHeadEntry overload in AggregateTable.findOrInsert
  
  dougqh
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  claude
  committed
  6a9063b
- Replace // nullable comments with @Nullable annotations on AggregateEntry
  
  dougqh
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  committed
  dbb1702
- Drop redundant load-factor comment from AggregateTable ctor
  
  dougqh
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  claude
  committed
  545e74c
- Import java.util.Objects in AggregateEntry instead of fully qualifying
  
  dougqh
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  claude
  committed
  9983a59
- Document evictOneStale cost and disable() best-effort offer
  
  dougqh
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  committed
  d2e4477
- Skip SpanSnapshot allocation when the inbox is already at capacity
  
  dougqh
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  claude
  committed
  24969db
Commits on May 20, 2026
- Hashtable: add missing braces and detach removed/replaced entries
  
  dougqh
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  claude
  committed
  66ec7f6
- Merge branch 'dougqh/util-hashtable' into dougqh/optimize-metric-key
  dougqh
  committed
  be823ab
- Add Hashtable and LongHashingUtils to datadog.trace.util
  
  dougqh
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  claude
  committed
  10956b2
- Add unit tests for Hashtable and LongHashingUtils
  
  dougqh
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  claude
  committed
  035dc09
- Apply spotless formatting to Hashtable and LongHashingUtils
  
  dougqh
  and
  claude
  committed
  7728b60
- Add JMH benchmarks for Hashtable.D1 and D2
  
  dougqh
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  claude
  committed
  8cd2d86
- Add benchmark results to HashtableBenchmark header
  
  dougqh
  and
  claude
  committed
  c689ef9
- Address review feedback on Hashtable
  
  dougqh
  and
  claude
  committed
  75790eb
- Fix dropped argument in HashingUtils 5-arg Object hash
  
  dougqh
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  claude
  committed
  6056ff7
- Address review feedback on Hashtable
  
  dougqh
  and
  claude
  committed
  da55021
- Drop reflection in iterator tests via package-private D1.buckets
  
  dougqh
  and
  claude
  committed
  8b8b088
- Add context-passing forEach to Hashtable.D1 and D2
  
  dougqh
  and
  claude
  committed
  0fde7cd
- Move forEach loop body to Support helper
  
  dougqh
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  claude
  committed
  6d6c2e0
- Move bucket-head cast to Support.bucket helper
  
  dougqh
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  claude
  committed
  268de2b
- Drop d1_/d2_ prefix from per-table benchmark methods
  
  dougqh
  and
  claude
  committed
  93813b9
- Add Hashtable.Support helpers: MAX_RATIO, insertHeadEntry, MutatingTableIterator
  
  dougqh
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  claude
  committed
  11a58bf
- Swap MAX_RATIO numerator/denominator pair for a single float + scaled create()
  
  dougqh
  and
  claude
  committed
  8f1828d
- Tighten Hashtable docs + rename MAX_CAPACITY to MAX_BUCKETS
  
  dougqh
  and
  claude
  committed
  c0d3e26
- Dedupe chain-head splice in D1/D2 via keyHash insertHeadEntry overload
  
  dougqh
  and
  claude
  committed
  a0978ba
- Tighten Entry.next encapsulation; doc hasNext; add D1/D2 getOrCreate
  
  dougqh
  and
  claude
  committed
  e604a8f
- Hashtable: add missing braces and detach removed/replaced entries
  
  dougqh
  and
  claude
  committed
  e2642cd
- Rename LongHashingUtils.hashCodeX(Object) to hash(Object) for API consistency
  
  dougqh
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  claude
  committed
  585ca56
- Merge remote-tracking branch 'origin/master' into dougqh/optimize-metric-key
  dougqh
  committed
  aab5b3b
- Merge branch 'dougqh/util-hashtable' into dougqh/optimize-metric-key
  dougqh
  committed
  88f169f
- Merge remote-tracking branch 'origin/master' into dougqh/conflating-metrics-background-work
  dougqh
  committed
  795ba76
- Introduce slim PeerTagSchema; capture peer-tag values not pairs
  
  dougqh
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  claude
  committed
  e455801
- Merge branch 'dougqh/conflating-metrics-background-work' into dougqh/optimize-metric-key
  dougqh
  committed
  c2ff012
Commits on May 21, 2026
- Address PR #11381 review (round 2)
  
  dougqh
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  claude
  committed
  e766fd3
- Cover inbox-full fast-path in ConflatingMetricsAggregator.publish
  
  dougqh
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  claude
  committed
  8cfa4a5
- Reconcile PeerTagSchema once per reporting cycle on the aggregator thread
  
  dougqh
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  claude
  committed
  3644470
- Merge branch 'dougqh/conflating-metrics-background-work' into dougqh/optimize-metric-key
  dougqh
  committed
  1d1ba4d
- Add bootstrap + reconcile coverage for PeerTagSchema
  
  dougqh
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  claude
  committed
  e7d0b42
- Merge branch 'dougqh/conflating-metrics-background-work' into dougqh/optimize-metric-key
  dougqh
  committed
  3d4f380
- Use writer.finishBucket() count in bootstrap test for cascade compatibility
  
  dougqh
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  claude
  committed
  9391c48
- Use writer.finishBucket() count in bootstrap test for cascade compatibility
  
  dougqh
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  claude
  committed
  ba3225c
- Merge branch 'master' into dougqh/conflating-metrics-background-work
  dougqh
  committed
  ec857b2
- Merge branch 'dougqh/conflating-metrics-background-work' into dougqh/optimize-metric-key
  dougqh
  committed
  ba0d390
- Preserve TRACER_METRICS_MAX_PENDING semantic + drop stale imports
  
  dougqh
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  claude
  committed
  0b86066
- Merge branch 'dougqh/conflating-metrics-background-work' into dougqh/optimize-metric-key
  dougqh
  committed
  f71384e
- Add AdversarialMetricsBenchmark for capacity-bound stress testing
  
  dougqh
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  claude
  committed
  5c78dbb
- Merge branch 'dougqh/conflating-metrics-background-work' into dougqh/optimize-metric-key
  dougqh
  committed
  471f8f7
- Trim AdversarialMetricsBenchmark counters and clarify printout
  
  dougqh
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  claude
  committed
  70c20ef
- Merge branch 'dougqh/conflating-metrics-background-work' into dougqh/optimize-metric-key
  dougqh
  committed
  7a074e0
- Close PeerTagSchema reconcile race + cover the swap branch
  
  dougqh
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  claude
  committed
  68848ad
- Merge branch 'dougqh/conflating-metrics-background-work' into dougqh/optimize-metric-key
  dougqh
  committed
  3fa7ac7
- Adapt reconcileSwapsSchemaWhenTagSetChanges to AggregateEntry shape
  
  dougqh
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  claude
  committed
  df3b31d
- Clarify materializePeerTags hit-counting loop
  
  dougqh
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  claude
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  2ea61c5
- Merge branch 'dougqh/conflating-metrics-background-work' into dougqh/optimize-metric-key
  dougqh
  committed
  8ec956d
- Fix MetricsIntegrationTest entry recording call site
  
  dougqh
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  claude
  committed
  a606692
- Make ConflatingMetricAggregatorTest counter checks actually verify
  
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  913e7d7
- Drop dead recordDurations(int, AtomicLongArray) batch API
  
  dougqh
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  2dcea9a
- Warn about colon split in AggregateEntry.of test factory
  
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  50b06e5
- Add coverage for disable() -> ClearSignal threading path
  
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  committed
  b0f21bf
- Drop unused Tags imports flagged by codenarc
  
  dougqh
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  5a4685f
- Merge branch 'dougqh/conflating-metrics-background-work' into dougqh/optimize-metric-key
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  committed
  200028d
Commits on May 22, 2026
- Update dd-trace-core/src/main/java/datadog/trace/common/metrics/PeerTagSchema.java
  
  dougqh
  and
  sarahchen6
  authored
  a1863db
- Address sarahchen6's review pass
  
  dougqh
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  claude
  committed
  a75bc4a
- Clamp TRACER_METRICS_MAX_PENDING instead of throwing on overflow
  
  dougqh
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  claude
  committed
  4871892
- Fix duplicate-entry bug for null-fielded SpanSnapshots
  
  dougqh
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  claude
  committed
  5f73c2d
- Clear dirty flag in ClearSignal handler
  
  dougqh
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  claude
  committed
  9dddf0a
- Merge branch 'master' into dougqh/conflating-metrics-background-work
  dougqh
  authored
  2c8ad26
- Drop conditional null-skip from peer-tag hashing
  
  dougqh
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  claude
  committed
  80778c4
- Delete dead Aggregator.clearAggregates()
  
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  21e7545
- Cursor-resume eviction in AggregateTable via half-open MutatingTableIterator
  
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  claude
  committed
  877d95c
- Move AggregateEntry.of() test factory out of production class
  
  dougqh
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  claude
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  e2f2585
- Fix AggregateEntry equals/hashCode contract violation
  
  dougqh
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  claude
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  2536aa2
- Don't trample queued STOP in ClearSignal handler
  
  dougqh
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  claude
  committed
  c0449a3
- Implement PeerTagSchema.equals symmetric with hashCode
  
  dougqh
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  be13431
- Route service and spanKind through canonicalize for null-safety
  
  dougqh
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  claude
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  d174938
- Suppress forbiddenApis for tearDown's System.err diagnostics
  
  dougqh
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  claude
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  641b5ef
- Merge branch 'master' into dougqh/conflating-metrics-background-work
  dougqh
  authored
  7eedb25
- Use DDAgentFeaturesDiscovery.state() hash for PeerTagSchema reconcile
  
  dougqh
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  claude
  committed
  ce5b38b
- Convert TRACER_METRICS_MAX_PENDING rationale to /* */ block comment
  
  dougqh
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  claude
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  2eaa58f
- Merge remote-tracking branch 'origin/dougqh/conflating-metrics-background-work' into dougqh/conflating-metrics-background-work
  dougqh
  committed
  cd56981
- Add cardinality-isolation companions to AdversarialMetricsBenchmark
  
  dougqh
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  claude
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  d1df95e
- Merge remote-tracking branch 'origin/dougqh/conflating-metrics-background-work' into dougqh/optimize-metric-key
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  committed
  4a4b72e
Commits on May 26, 2026
- Consolidate contentEquals; remove redundant stringContentEquals
  
  dougqh
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  claude
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  133d3c1
- Rename AggregateEntries -> AggregateEntryFixtures
  
  dougqh
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  claude
  committed
  2ae738b
- Tidy PR-iteration history out of test comments
  
  dougqh
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  claude
  committed
  f68ad4f
- Merge remote-tracking branch 'origin/master' into dougqh/optimize-metric-key
  dougqh
  committed
  6fdc2de
- Merge remote-tracking branch 'origin/master' into dougqh/optimize-metric-key
  dougqh
  committed
  3f32dfd
- Make AggregateEntry.ERROR_TAG / TOP_LEVEL_TAG package-private
  
  dougqh
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  claude
  committed
  2d1536c
- Move AggregateEntry equality contract to test-only helper
  
  dougqh
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  claude
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  5bf4d90
- Consolidate AggregateEntryFixtures into AggregateEntryTestUtils
  
  dougqh
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  claude
  committed
  a67ac23
- Document deliberate cohesion + single-writer invariant on AggregateEntry
  
  dougqh
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  claude
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  1eb6826
- Avoid recomputing keyHash on AggregateTable miss
  
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  d5065f2
Commits on May 27, 2026
- Document AggregateEntry.clear key-field persistence + SignalItem singleton contract
  
  dougqh
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  claude
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  e6f2399
- Drop useless @SuppressFBWarnings on AggregateEntry
  
  dougqh
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  claude
  committed
  dcb1898
- Update stale Javadoc on AggregateEntry's no-equals contract
  
  dougqh
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  claude
  committed
  a06c2a8
- Tighten AggregateEntry / PeerTagSchema surface area
  
  dougqh
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  claude
  committed
  acf2ffa
- Tighten AggregateEntry surface — drop one-line factory, doc the conventions
  
  dougqh
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  claude
  committed
  ccb4a4b
- Merge branch 'master' into dougqh/optimize-metric-key
  dougqh
  authored
  d0c0be8
- Drop unused UTF8BytesString import in MetricsIntegrationTest
  
  dougqh
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  claude
  committed
  4af16c1
- Merge branch 'master' into dougqh/optimize-metric-key
  dougqh
  authored
  dcd3407
- Lazy-allocate the error latency histogram on AggregateEntry
  
  dougqh
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  claude
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  f2ee559
Commits on May 28, 2026
- Add MpscRingBuffer for pre-allocated, recyclable slot rings
  
  dougqh
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  claude
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  1d12490
- Add throughput benchmarks for MpscRingBuffer
  
  dougqh
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  16b2ec6
- Add RingVsQueueBenchmark for MpscRingBuffer vs MpscArrayQueue
  
  dougqh
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  claude
  committed
  e67dde7
- Merge dougqh/ring-buffer into dougqh/css-ring-buffer
  dougqh
  committed
  059063f
- Swap CSS inbox for MpscRingBuffer of mutable SpanSnapshot slots
  
  dougqh
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  claude
  committed
  7ec3f11
- Document MpscRingBuffer thread-safety contract; publish on filler throw
  
  dougqh
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  claude
  committed
  cec6abf
- Merge dougqh/ring-buffer into dougqh/css-ring-buffer
  dougqh
  committed
  1940355
- Use AtomicLongFieldUpdater for the producer cursor
  
  dougqh
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  claude
  committed
  9162a1e
- Merge dougqh/ring-buffer: pick up AtomicLongFieldUpdater change
  dougqh
  committed
  12984ac
- Pad MpscRingBuffer cursors and stride publishedSequences
  
  dougqh
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  claude
  committed
  e8ead01
- Merge dougqh/ring-buffer: cache-line padding + stride
  dougqh
  committed
  fed8238
- Shrink tracer.metrics defaults at Xmx<128m for the ring buffer
  
  dougqh
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  claude
  committed
  ef046be
- Cut default tracer.metrics.max.pending from 2048 to 128
  
  dougqh
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  claude
  committed
  525599e
- Reuse peerTagValues array across publishes via slot-owned scratch
  
  dougqh
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  claude
  committed
  c31715f
- Add MpscRingBuffer.tryClaim(n) batch-claim API
  
  dougqh
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  claude
  committed
  7e6f497
- Merge dougqh/ring-buffer: pick up tryClaim(n)/Batch API
  dougqh
  committed
  01754a5
- Use Batch claim for CSS publish(trace)
  
  dougqh
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  claude
  committed
  3324952
- Add low-level tryClaimRange/slotAt/publish primitives to MpscRingBuffer
  
  dougqh
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  claude
  committed
  780a204
- Merge dougqh/ring-buffer: pick up low-level primitives
  dougqh
  committed
  f18a73e
- Use MpscRingBuffer low-level primitives in publish(trace)
  
  dougqh
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  claude
  committed
  32c69d1
- Fix stale Javadoc reference to removed slotFiller field
  
  dougqh
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  claude
  committed
  e4277d0
- Overclaim + skip-sentinel in CSS publish(trace): one pass, no Batch
  
  dougqh
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  claude
  committed
  fb14c62
- Use PendingTrace pre-counted eligible-span count for exact CSS ring claim
  
  dougqh
  and
  claude
  committed
  e29b802
- Revert "Use PendingTrace pre-counted eligible-span count for exact CSS ring claim"
  dougqh
  committed
  21b5bd7
Commits on May 29, 2026
- Park/unpark aggregator and cache PeerTagSchema.namesHash
  
  dougqh
  and
  claude
  committed
  a39ede1
- Canonicalize + hash on the producer; identity matches on the aggregator
  
  dougqh
  and
  claude
  committed
  c330d9c

Commits

Commits on May 15, 2026

Commits on May 18, 2026

Commits on May 19, 2026

Commits on May 20, 2026

Commits on May 21, 2026

Commits on May 22, 2026

Commits on May 26, 2026

Commits on May 27, 2026