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Add client-side trace stats computation that aggregates span metrics
(hits, errors, duration distributions) into 10-second time buckets
and flushes them to the Datadog Agent via POST /v0.6/stats.
This enables the Agent to drop priority-0 (unsampled) traces without
losing service-level metrics.
Key components:
- DDSketch: minimal C++ implementation with 1% relative accuracy, 2048
max bins, and msgpack serialization
- StatsConcentrator: aggregates eligible spans by 12 dimensions
(service, name, resource, type, HTTP/gRPC status codes, span_kind,
synthetics, is_trace_root, peer_tags, HTTP method/endpoint)
- Stats flusher: fire-and-forget POST /v0.6/stats with msgpack payload
- Config: DD_TRACE_STATS_COMPUTATION_ENABLED env var (default: false)
- Headers: Datadog-Client-Computed-Stats, Datadog-Client-Computed-Top-Level
Span eligibility: top-level OR measured OR span.kind in
{server, client, producer, consumer}.
Co-Authored-By: Claude Sonnet 4.6 (1M context) <noreply@anthropic.com>
- GRPCStatusCode: serialize as string instead of uint32 to match protobuf definition (string GRPC_status_code = 18) - PeerTags: serialize as msgpack array of "key:value" strings instead of a single comma-separated string (repeated string peer_tags = 16) - Peer tag separator: use ":" instead of "=" to match Go/Java/Python/Ruby - Peer tag keys: update to match Go agent standard (8 keys instead of 17) Co-Authored-By: Claude Sonnet 4.6 (1M context) <noreply@anthropic.com>
The /v0.6/stats payload was missing TracerVersion, RuntimeID, Sequence, and Service fields required by the spec. Add these four fields to the top-level msgpack map (now 9 keys instead of 5), with Sequence as a monotonically increasing counter that increments on each flush. Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
bm1549
added
the
AI Generated
Fix clang-format violations in stats_concentrator.cpp, stats_concentrator.h, and test_stats_concentrator.cpp caught by the verify CI job. Co-Authored-By: Claude Sonnet 4.6 (1M context) <noreply@anthropic.com>
BenchmarksBenchmark execution time: 2026-03-19 17:11:53 Comparing candidate commit 0bc8472 in PR branch Found 0 performance improvements and 0 performance regressions! Performance is the same for 1 metrics, 0 unstable metrics. |
…NABLED Regenerate supported-configurations.json to include the new DD_TRACE_STATS_COMPUTATION_ENABLED env var added in environment.h. Co-Authored-By: Claude Sonnet 4.6 (1M context) <noreply@anthropic.com>
The new source files ddsketch.{cpp,h} and stats_concentrator.{cpp,h}
were missing from the Bazel cc_library srcs list, causing Bazel builds
to fail with 'stats_concentrator.h file not found'.
Co-Authored-By: Claude Sonnet 4.6 (1M context) <noreply@anthropic.com>
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Summary
Implements Client-Side Trace Stats Computation (CSS) from scratch, matching the Go reference implementation.
/v0.6/statsTest plan
Part of cross-tracer CSS v1.3.0 alignment effort.
🤖 Generated with Claude Code