[SVLS-8734] fix(traces): restore _dd.compute_stats to span meta to fix missing trace stats#1172
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[SVLS-8734] fix(traces): restore _dd.compute_stats to span meta to fix missing trace stats#1172
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…ace.aws.lambda.hits PR #1118 moved `_dd.compute_stats` from each span's `meta` (applied via `get_tags_map()` / `ChunkProcessor`) to the payload-level `tracer_payload.tags` only. The Datadog APM backend reads this signal from the root span's `meta` field, not from the payload-level tags, so it stopped computing stats and `trace.aws.lambda.hits` disappeared from the trace explorer. Fix: propagate `_dd.compute_stats` to every span's `meta` in the same loop that writes it to `tracer_payload.tags`, restoring the pre-#1118 behavior while keeping the payload-level tag as well. Also add debug logging to `handle_traces` to surface the header tags on every incoming trace request, which aids diagnosing similar issues. Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
…n span meta Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
…om payload tags - Add `compute_stats_value` field to `ChunkProcessor` so the tag is set on each span's meta alongside the other function tags, instead of in a separate post-processing loop. - Remove `_dd.compute_stats` from `tracer_payload.tags`: it was never set there before PR #1118 and is not needed — stats work via the span meta path alone. - Compute and log the value once at the top of `process_traces`, before constructing `ChunkProcessor`. Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
lym953
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Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
…ad of pre-computed value Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
…bda_span to check span meta _dd.compute_stats is now set on span meta instead of payload tags. Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
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Pull request overview
This PR fixes the missing trace stats issue by restoring _dd.compute_stats to span metadata. PR #1118 had moved this tag to payload-level tags, but the backend expects it on individual spans to properly calculate trace statistics.
Changes:
- Move
_dd.compute_statsback into individual span'smetafield (previously moved to payload tags in PR #1118) - Add
client_computed_stats: boolfield toChunkProcessorto track whether client has already computed stats - Remove
_dd.compute_statsfromtracer_payload.tagswhere it was incorrectly placed - Update tests to verify the tag is set on spans, not on payload level
Reviewed changes
Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.
| File | Description |
|---|---|
| bottlecap/src/traces/trace_processor.rs | Moves _dd.compute_stats logic to ChunkProcessor::process() to set it on each span's meta based on both compute_trace_stats_on_extension and client_computed_stats config, removes the incorrect payload-level tag setting, and updates all related tests |
| bottlecap/src/lifecycle/invocation/processor.rs | Updates test assertions to verify _dd.compute_stats is in span metadata rather than payload tags |
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duncanista
approved these changes
Apr 8, 2026
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Aborting because stats don't work for Go and Java: From @purple4reina ,
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Problem
PR #1118 (SVLS-8734) moved
_dd.compute_statsfrom each span'smetafield to the payload-level
tracer_payload.tagsmap only. This causedtrace stats such as
trace.aws.lambda.hitsto disappear from the trace explorer.The observed debug log that surfaced the issue:
Fix
_dd.compute_statsback intoChunkProcessor::process(), where it isset on each span's
metaalongside all other function tags. This restoresthe pre-feat(traces): [SVLS-8734] respect Datadog-Client-Computed-Stats header #1118 behavior regarding there the tag is set.
_dd.compute_statsfromtracer_payload.tags: it was never set therebefore feat(traces): [SVLS-8734] respect Datadog-Client-Computed-Stats header #1118 and is not needed.
ChunkProcessorgains aclient_computed_stats: boolfield (fromheader_tags); the"1"/"0"value is computed insideprocess()usingself.config.compute_trace_stats_on_extensionandself.client_computed_stats.Test plan
Automated tests
All 17 tests pass, including all 4
test_compute_stats_tag_*variants.Manual tests
Test 1: Missing trace stats issue is fixed
Steps
DD_COMPUTE_TRACE_STATS_ON_EXTENSIONorDD_TRACE_STATS_COMPUTATION_ENABLEDResult
In Metrics Explorer,
trace.aws.lambda.hitsshows 1 hit.Test 2: Duplicate trace stats issue is still fixed
Steps
github.com/DataDog/dd-trace-go/v2 v2.6.0DD_TRACE_STATS_COMPUTATION_ENABLED:true, which turns on client-side statsDD_COMPUTE_TRACE_STATS_ON_EXTENSION:true, which tries to turn on extension side statsResult
Still only 1 hit with
resource_name=dd-tracer-serverless-span, which means the double counting that #1118 was trying to fix is still fixed.Next steps
Once serverless-e2e-tests deployment is fixed, run the e2e tests and ensure trace stats look good.