Stream the body in the trace-agent dogstatsd proxy

[ajgajg1134]

What does this PR do?

Replaces the eager bytes.Split in the trace-agent dogstatsd proxy handler
(/dogstatsd/v1/proxy, /dogstatsd/v2/proxy) with a bufio.Scanner that walks
the request body one payload at a time, and:

• skips empty payloads, which carry nothing for dogstatsd to parse
• caps the payloads relayed per request (maxDogstatsdProxyPayloads, 100k),
  returning 413 beyond that

Motivation

The handler read the whole body and then split it on newlines before relaying
each payload over UDP. bytes.Split pre-materializes one 24-byte slice header
per newline byte, so a body made mostly of newlines used several times its own
size in memory — at the default 25MB body limit that is hundreds of MB of
headers, and the memory is not returned promptly afterwards. Separately, the
number of UDP writes one request could drive was bounded only by the body size.

Scanning keeps the extra memory proportional to the longest line, and the cap
keeps the writes a single request can cause to a fixed cost.

Describe how you validated your changes

TestDogStatsDReverseProxyPayloadRelay is a table test binding a real UDP
socket and asserting both the status code and what actually reaches dogstatsd:

subtest	body	expects
newlines only	100k newlines	200, nothing relayed
unreadable body	one line then a failing reader	500, first line relayed
body over size limit	limit cuts mid second line	500, first line relayed
more payloads than the proxy relays	cap + 1 lines	413, first payload relayed

The pre-existing end-to-end UDP and UDS proxy tests still pass, and the whole
package passes with -test.short=false (545 tests). dda inv linter.go --targets=./pkg/trace/api is clean.

Additional Notes

The bufio.Scanner default 64KiB token limit is above the maximum UDP payload
(65507 bytes), so it cannot reject a payload that would otherwise have been
deliverable.

[datadog-datadog-prod-us1-2]

🎯 Code Coverage (details)
• Patch Coverage: 93.33%
• Overall Coverage: 52.34% (+0.05%)

_{This comment will be updated automatically if new data arrives.
🔗 Commit SHA: a00b33c | Docs | Datadog PR Page | Give us feedback!}

[dd-octo-sts]

Files inventory check summary

File checks results against ancestor 1d86ce75:

Results for datadog-agent_7.84.0~devel.git.51.a00b33c.pipeline.130019822-1_amd64.deb:

No change detected

Results for datadog-iot-agent_7.84.0~devel.git.51.a00b33c.pipeline.130019822-1_amd64.deb:

No change detected

[dd-octo-sts]

Static quality checks

✅ Please find below the results from static quality gates
Comparison made with ancestor 1d86ce7
📊 Static Quality Gates Dashboard
🔗 SQG Job

Successful checks

Info

	Quality gate	Change	Size (prev → curr → max)
✅	agent_deb_amd64	+4.0 KiB (0.00% increase, -0.08% of buffer)	759.542 → 759.546 → 764.430
✅	agent_heroku_amd64	+4.0 KiB (0.00% increase, -0.06% of buffer)	312.265 → 312.269 → 318.990
✅	agent_rpm_amd64	+4.0 KiB (0.00% increase, -0.08% of buffer)	759.526 → 759.530 → 764.400
✅	agent_suse_amd64	+4.0 KiB (0.00% increase, -0.08% of buffer)	759.526 → 759.530 → 764.400
✅	docker_agent_amd64	+4.0 KiB (0.00% increase, -0.21% of buffer)	818.154 → 818.158 → 819.970
✅	docker_agent_jmx_amd64	+4.0 KiB (0.00% increase, -0.23% of buffer)	1009.051 → 1009.055 → 1010.730

26 successful checks with minimal change (< 2 KiB)

	Quality gate	Current Size
✅	agent_deb_amd64_fips	712.884 MiB
✅	agent_rpm_amd64_fips	712.868 MiB
✅	agent_rpm_arm64	735.491 MiB
✅	agent_rpm_arm64_fips	692.100 MiB
✅	agent_suse_amd64_fips	712.868 MiB
✅	agent_suse_arm64	735.491 MiB
✅	agent_suse_arm64_fips	692.100 MiB
✅	docker_agent_arm64	819.162 MiB
✅	docker_agent_jmx_arm64	998.712 MiB
✅	docker_cluster_agent_amd64	210.228 MiB
✅	docker_cluster_agent_arm64	223.267 MiB
✅	docker_cws_instrumentation_amd64	7.439 MiB
✅	docker_cws_instrumentation_arm64	6.877 MiB
✅	docker_dogstatsd_amd64	39.479 MiB
✅	docker_dogstatsd_arm64	37.623 MiB
✅	docker_host_profiler_amd64	305.801 MiB
✅	docker_host_profiler_arm64	317.115 MiB
✅	dogstatsd_deb_amd64	30.220 MiB
✅	dogstatsd_deb_arm64	28.244 MiB
✅	dogstatsd_rpm_amd64	30.220 MiB
✅	dogstatsd_suse_amd64	30.220 MiB
✅	iot_agent_deb_amd64	46.416 MiB
✅	iot_agent_deb_arm64	43.091 MiB
✅	iot_agent_deb_armhf	43.871 MiB
✅	iot_agent_rpm_amd64	46.416 MiB
✅	iot_agent_suse_amd64	46.415 MiB

[cit-pr-commenter-54b7da]

Regression Detector

Regression Detector Results

Metrics dashboard
Target profiles
Run ID: 75096eed-420c-4644-bc4f-d324235c9a0a

Baseline: 1d86ce7
Comparison: a00b33c
Diff

Optimization Goals: ✅ No significant changes detected

Fine details of change detection per experiment

perf	experiment	goal	Δ mean %	Δ mean % CI	trials	links
➖	quality_gate_private_action_runner	memory utilization	+0.80	[+0.69, +0.92]	1	Logs bounds checks dashboard
➖	quality_gate_security_idle	memory utilization	+0.39	[+0.33, +0.45]	1	Logs bounds checks dashboard
➖	quality_gate_security_no_fs_load	memory utilization	+0.31	[+0.22, +0.41]	1	Logs bounds checks dashboard
➖	quality_gate_idle_all_features	memory utilization	+0.20	[+0.16, +0.23]	1	Logs bounds checks dashboard
➖	quality_gate_logs	% cpu utilization	+0.10	[-0.73, +0.94]	1	Logs bounds checks dashboard
➖	quality_gate_idle	memory utilization	+0.09	[+0.04, +0.14]	1	Logs bounds checks dashboard
➖	quality_gate_security_mean_fs_load	memory utilization	-0.05	[-0.09, -0.02]	1	Logs bounds checks dashboard
➖	quality_gate_metrics_logs	memory utilization	-0.73	[-0.98, -0.49]	1	Logs bounds checks dashboard

Bounds Checks: ✅ Passed

perf	experiment	bounds_check_name	replicates_passed	observed_value	links
✅	quality_gate_idle	intake_connections	10/10	3 ≤ 4	bounds checks dashboard
✅	quality_gate_idle	memory_usage	10/10	148.51MiB ≤ 154MiB	bounds checks dashboard
✅	quality_gate_idle	total_bytes_received	10/10	734.17KiB ≤ 819.20KiB	bounds checks dashboard
✅	quality_gate_idle_all_features	intake_connections	10/10	3 ≤ 4	bounds checks dashboard
✅	quality_gate_idle_all_features	memory_usage	10/10	490.39MiB ≤ 512MiB	bounds checks dashboard
✅	quality_gate_idle_all_features	total_bytes_received	10/10	1.13MiB ≤ 1.25MiB	bounds checks dashboard
✅	quality_gate_logs	intake_connections	10/10	18 ≤ 40	bounds checks dashboard
✅	quality_gate_logs	memory_usage	10/10	186.05MiB ≤ 195MiB	bounds checks dashboard
✅	quality_gate_logs	missed_bytes	10/10	0B = 0B	bounds checks dashboard
✅	quality_gate_logs	total_bytes_received	10/10	264.18MiB ≤ 292MiB	bounds checks dashboard
✅	quality_gate_metrics_logs	cpu_usage	10/10	351.67 ≤ 2000	bounds checks dashboard
✅	quality_gate_metrics_logs	intake_connections	10/10	18 ≤ 40	bounds checks dashboard
✅	quality_gate_metrics_logs	memory_usage	10/10	384.62MiB ≤ 430MiB	bounds checks dashboard
✅	quality_gate_metrics_logs	missed_bytes	10/10	0B = 0B	bounds checks dashboard
✅	quality_gate_metrics_logs	total_bytes_received	10/10	0.94GiB ≤ 1.04GiB	bounds checks dashboard
✅	quality_gate_private_action_runner	memory_usage	10/10	71.66MiB ≤ 75MiB	bounds checks dashboard
✅	quality_gate_security_idle	cpu_usage	10/10	29.46 ≤ 100	bounds checks dashboard
✅	quality_gate_security_idle	memory_usage	10/10	304.01MiB ≤ 330MiB	bounds checks dashboard
✅	quality_gate_security_mean_fs_load	cpu_usage	10/10	60.55 ≤ 200	bounds checks dashboard
✅	quality_gate_security_mean_fs_load	memory_usage	10/10	277.50MiB ≤ 310MiB	bounds checks dashboard
✅	quality_gate_security_no_fs_load	cpu_usage	10/10	20.11 ≤ 100	bounds checks dashboard
✅	quality_gate_security_no_fs_load	memory_usage	10/10	287.23MiB ≤ 320MiB	bounds checks dashboard

Explanation

Confidence level: 90.00%
Effect size tolerance: |Δ mean %| ≥ 5.00%

Performance changes are noted in the perf column of each table:

• ✅ = significantly better comparison variant performance
• ❌ = significantly worse comparison variant performance
• ➖ = no significant change in performance

A regression test is an A/B test of target performance in a repeatable rig, where "performance" is measured as "comparison variant minus baseline variant" for an optimization goal (e.g., ingress throughput). Due to intrinsic variability in measuring that goal, we can only estimate its mean value for each experiment; we report uncertainty in that value as a 90.00% confidence interval denoted "Δ mean % CI".

For each experiment, we decide whether a change in performance is a "regression" -- a change worth investigating further -- if all of the following criteria are true:

1. Its estimated |Δ mean %| ≥ 5.00%, indicating the change is big enough to merit a closer look.

2. Its 90.00% confidence interval "Δ mean % CI" does not contain zero, indicating that if our statistical model is accurate, there is at least a 90.00% chance there is a difference in performance between baseline and comparison variants.

3. Its configuration does not mark it "erratic".

Replicate Execution Details

We run multiple replicates for each experiment/variant. However, we allow replicates to be automatically retried if there are any failures, up to 8 times, at which point the replicate is marked dead and we are unable to run analysis for the entire experiment. We call each of these attempts at running replicates a replicate execution. This section lists all replicate executions that failed due to the target crashing or being oom killed.

Note: In the below tables we bucket failures by experiment, variant, and failure type. For each of these buckets we list out the replicate indexes that failed with an annotation signifying how many times said replicate failed with the given failure mode. In the below example the baseline variant of the experiment named experiment_with_failures had two replicates that failed by oom kills. Replicate 0, which failed 8 executions, and replicate 1 which failed 6 executions, all with the same failure mode.

Experiment	Variant	Replicates	Failure	Logs	Debug Dashboard
experiment_with_failures	baseline	0 (x8) 1 (x6)	Oom killed		Debug Dashboard

The debug dashboard links will take you to a debugging dashboard specifically designed to investigate replicate execution failures.

❌ Retried Profiling Replicate Execution Failures (ddprof)

Note: Profiling replicas may still be executing. See the debug dashboard for up to date status.

Experiment	Variant	Replicates	Failure	Debug Dashboard
quality_gate_idle	baseline	10	Oom killed	Debug Dashboard
quality_gate_idle	comparison	10	Oom killed	Debug Dashboard
quality_gate_idle_all_features	baseline	10	Oom killed	Debug Dashboard
quality_gate_idle_all_features	comparison	10	Oom killed	Debug Dashboard
quality_gate_logs	comparison	10	Oom killed	Debug Dashboard
quality_gate_metrics_logs	baseline	10	Oom killed	Debug Dashboard
quality_gate_metrics_logs	comparison	10	Oom killed	Debug Dashboard
quality_gate_security_idle	baseline	10	Crashed (exit code: 134)	Debug Dashboard
quality_gate_security_idle	comparison	10	Oom killed	Debug Dashboard
quality_gate_security_mean_fs_load	baseline	10	Crashed (exit code: 134)	Debug Dashboard
quality_gate_security_mean_fs_load	comparison	10	Oom killed	Debug Dashboard
quality_gate_security_no_fs_load	baseline	10	Crashed (exit code: 134)	Debug Dashboard
quality_gate_security_no_fs_load	comparison	10	Crashed (exit code: 134)	Debug Dashboard

CI Pass/Fail Decision

✅ Passed. All Quality Gates passed.

• quality_gate_logs, bounds check total_bytes_received: 10/10 replicas passed. Gate passed.
• quality_gate_logs, bounds check missed_bytes: 10/10 replicas passed. Gate passed.
• quality_gate_logs, bounds check intake_connections: 10/10 replicas passed. Gate passed.
• quality_gate_logs, bounds check memory_usage: 10/10 replicas passed. Gate passed.
• quality_gate_idle_all_features, bounds check memory_usage: 10/10 replicas passed. Gate passed.
• quality_gate_idle_all_features, bounds check intake_connections: 10/10 replicas passed. Gate passed.
• quality_gate_idle_all_features, bounds check total_bytes_received: 10/10 replicas passed. Gate passed.
• quality_gate_security_no_fs_load, bounds check cpu_usage: 10/10 replicas passed. Gate passed.
• quality_gate_security_no_fs_load, bounds check memory_usage: 10/10 replicas passed. Gate passed.
• quality_gate_idle, bounds check intake_connections: 10/10 replicas passed. Gate passed.
• quality_gate_idle, bounds check memory_usage: 10/10 replicas passed. Gate passed.
• quality_gate_idle, bounds check total_bytes_received: 10/10 replicas passed. Gate passed.
• quality_gate_security_idle, bounds check cpu_usage: 10/10 replicas passed. Gate passed.
• quality_gate_security_idle, bounds check memory_usage: 10/10 replicas passed. Gate passed.
• quality_gate_security_mean_fs_load, bounds check memory_usage: 10/10 replicas passed. Gate passed.
• quality_gate_security_mean_fs_load, bounds check cpu_usage: 10/10 replicas passed. Gate passed.
• quality_gate_metrics_logs, bounds check intake_connections: 10/10 replicas passed. Gate passed.
• quality_gate_metrics_logs, bounds check missed_bytes: 10/10 replicas passed. Gate passed.
• quality_gate_metrics_logs, bounds check memory_usage: 10/10 replicas passed. Gate passed.
• quality_gate_metrics_logs, bounds check cpu_usage: 10/10 replicas passed. Gate passed.
• quality_gate_metrics_logs, bounds check total_bytes_received: 10/10 replicas passed. Gate passed.
• quality_gate_private_action_runner, bounds check memory_usage: 10/10 replicas passed. Gate passed.

[ajgajg1134]

/merge

[gh-worker-devflow-routing-ef8351]

View all feedbacks in Devflow UI.

2026-08-11 13:25:48 UTC ℹ️ Start processing command /merge

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2026-08-11 13:25:53 UTC ℹ️ MergeQueue: pull request added to the queue

The expected merge time in main is approximately 1h (p90).

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2026-08-11 13:59:54 UTC ℹ️ MergeQueue: Readding this merge request to the queue because another merge request processed with yours failed. No action is needed from your side.

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2026-08-11 14:56:14 UTC ℹ️ MergeQueue: This merge request was merged