SVLS-8771 fix cloud run jobs shutdown race#47827
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Files inventory check summaryFile checks results against ancestor e1d852a8: Results for datadog-agent_7.78.0~devel.git.647.2f1a657.pipeline.102967417-1_amd64.deb:Detected file changes:
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Regression DetectorRegression Detector ResultsMetrics dashboard Baseline: 71d35a4 Optimization Goals: ✅ No significant changes detected
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| perf | experiment | goal | Δ mean % | Δ mean % CI | trials | links |
|---|---|---|---|---|---|---|
| ➖ | docker_containers_cpu | % cpu utilization | +1.12 | [-1.90, +4.15] | 1 | Logs |
Fine details of change detection per experiment
| perf | experiment | goal | Δ mean % | Δ mean % CI | trials | links |
|---|---|---|---|---|---|---|
| ➖ | docker_containers_cpu | % cpu utilization | +1.12 | [-1.90, +4.15] | 1 | Logs |
| ➖ | quality_gate_metrics_logs | memory utilization | +0.48 | [+0.24, +0.72] | 1 | Logs bounds checks dashboard |
| ➖ | otlp_ingest_metrics | memory utilization | +0.33 | [+0.17, +0.49] | 1 | Logs |
| ➖ | ddot_metrics_sum_cumulativetodelta_exporter | memory utilization | +0.32 | [+0.09, +0.54] | 1 | Logs |
| ➖ | ddot_logs | memory utilization | +0.23 | [+0.18, +0.29] | 1 | Logs |
| ➖ | otlp_ingest_logs | memory utilization | +0.12 | [+0.02, +0.22] | 1 | Logs |
| ➖ | quality_gate_idle | memory utilization | +0.08 | [+0.03, +0.13] | 1 | Logs bounds checks dashboard |
| ➖ | quality_gate_idle_all_features | memory utilization | +0.07 | [+0.04, +0.11] | 1 | Logs bounds checks dashboard |
| ➖ | file_to_blackhole_0ms_latency | egress throughput | +0.06 | [-0.45, +0.56] | 1 | Logs |
| ➖ | file_to_blackhole_100ms_latency | egress throughput | +0.04 | [-0.04, +0.12] | 1 | Logs |
| ➖ | ddot_metrics | memory utilization | +0.03 | [-0.15, +0.22] | 1 | Logs |
| ➖ | file_to_blackhole_500ms_latency | egress throughput | +0.01 | [-0.37, +0.40] | 1 | Logs |
| ➖ | tcp_dd_logs_filter_exclude | ingress throughput | +0.01 | [-0.10, +0.12] | 1 | Logs |
| ➖ | docker_containers_memory | memory utilization | +0.01 | [-0.07, +0.09] | 1 | Logs |
| ➖ | file_to_blackhole_1000ms_latency | egress throughput | +0.00 | [-0.43, +0.44] | 1 | Logs |
| ➖ | uds_dogstatsd_to_api | ingress throughput | -0.01 | [-0.21, +0.20] | 1 | Logs |
| ➖ | uds_dogstatsd_to_api_v3 | ingress throughput | -0.01 | [-0.20, +0.19] | 1 | Logs |
| ➖ | uds_dogstatsd_20mb_12k_contexts_20_senders | memory utilization | -0.03 | [-0.09, +0.04] | 1 | Logs |
| ➖ | file_tree | memory utilization | -0.09 | [-0.15, -0.03] | 1 | Logs |
| ➖ | ddot_metrics_sum_cumulative | memory utilization | -0.14 | [-0.28, +0.00] | 1 | Logs |
| ➖ | ddot_metrics_sum_delta | memory utilization | -0.30 | [-0.47, -0.14] | 1 | Logs |
| ➖ | tcp_syslog_to_blackhole | ingress throughput | -0.63 | [-0.77, -0.49] | 1 | Logs |
| ➖ | quality_gate_logs | % cpu utilization | -1.72 | [-3.32, -0.13] | 1 | Logs bounds checks dashboard |
Bounds Checks: ✅ Passed
| perf | experiment | bounds_check_name | replicates_passed | observed_value | links |
|---|---|---|---|---|---|
| ✅ | docker_containers_cpu | simple_check_run | 10/10 | 722 ≥ 26 | |
| ✅ | docker_containers_memory | memory_usage | 10/10 | 273.48MiB ≤ 370MiB | |
| ✅ | docker_containers_memory | simple_check_run | 10/10 | 714 ≥ 26 | |
| ✅ | file_to_blackhole_0ms_latency | memory_usage | 10/10 | 0.19GiB ≤ 1.20GiB | |
| ✅ | file_to_blackhole_0ms_latency | missed_bytes | 10/10 | 0B = 0B | |
| ✅ | file_to_blackhole_1000ms_latency | memory_usage | 10/10 | 0.23GiB ≤ 1.20GiB | |
| ✅ | file_to_blackhole_1000ms_latency | missed_bytes | 10/10 | 0B = 0B | |
| ✅ | file_to_blackhole_100ms_latency | memory_usage | 10/10 | 0.19GiB ≤ 1.20GiB | |
| ✅ | file_to_blackhole_100ms_latency | missed_bytes | 10/10 | 0B = 0B | |
| ✅ | file_to_blackhole_500ms_latency | memory_usage | 10/10 | 0.22GiB ≤ 1.20GiB | |
| ✅ | file_to_blackhole_500ms_latency | missed_bytes | 10/10 | 0B = 0B | |
| ✅ | quality_gate_idle | intake_connections | 10/10 | 3 = 3 | bounds checks dashboard |
| ✅ | quality_gate_idle | memory_usage | 10/10 | 173.66MiB ≤ 175MiB | bounds checks dashboard |
| ✅ | quality_gate_idle_all_features | intake_connections | 10/10 | 2 ≤ 3 | bounds checks dashboard |
| ✅ | quality_gate_idle_all_features | memory_usage | 10/10 | 489.40MiB ≤ 550MiB | bounds checks dashboard |
| ✅ | quality_gate_logs | intake_connections | 10/10 | 3 ≤ 6 | bounds checks dashboard |
| ✅ | quality_gate_logs | memory_usage | 10/10 | 204.61MiB ≤ 220MiB | bounds checks dashboard |
| ✅ | quality_gate_logs | missed_bytes | 10/10 | 0B = 0B | bounds checks dashboard |
| ✅ | quality_gate_metrics_logs | cpu_usage | 10/10 | 343.47 ≤ 2000 | bounds checks dashboard |
| ✅ | quality_gate_metrics_logs | intake_connections | 10/10 | 3 ≤ 6 | bounds checks dashboard |
| ✅ | quality_gate_metrics_logs | memory_usage | 10/10 | 414.70MiB ≤ 475MiB | bounds checks dashboard |
| ✅ | quality_gate_metrics_logs | missed_bytes | 10/10 | 0B = 0B | 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:
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Its estimated |Δ mean %| ≥ 5.00%, indicating the change is big enough to merit a closer look.
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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.
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Its configuration does not mark it "erratic".
CI Pass/Fail Decision
✅ Passed. All Quality Gates 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_logs, bounds check missed_bytes: 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 memory_usage: 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 intake_connections: 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, bounds check memory_usage: 10/10 replicas passed. Gate passed.
- quality_gate_idle, bounds check intake_connections: 10/10 replicas passed. Gate passed.
Static quality checks✅ Please find below the results from static quality gates 30 successful checks with minimal change (< 2 KiB)
On-wire sizes (compressed)
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| case ms := <-w.samplesChan: | ||
| w.processSamples(ms) | ||
| default: |
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Bound sample draining before flush to avoid flush starvation
The new flush path drains samplesChan until it is empty, but in the agent demultiplexer AggregateSamples can keep feeding that channel concurrently while the flush loop waits synchronously for t.blockChan. Under sustained DogStatsD traffic, this loop may never observe the channel empty, so triggerFlush is never reached; that blocks periodic/manual flushes and can also stall shutdown progress because stopChan is not checked inside drainSamples.
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Summary
- Addressed the review feedback on
pkg/aggregator/time_sampler_worker.goby updatingdrainSamples()to consume exactly the snapshotted buffered count (n := len(samplesChan)) without adefaultbranch, preventing premature exit while keeping drain bounded and non-starvable by concurrent producers. pkg/aggregator/time_sampler_worker.goL137-L150 - Added an in-code rationale clarifying why receiving exactly
nitems cannot block in this worker model (single consumer onsamplesChan). pkg/aggregator/time_sampler_worker.goL144-L148 - Committed the change on branch
workas commit1e3946eb, and created the follow-up PR record viamake_prwith a summary and validation steps.
Testing
⚠️ python - <<'PY' ... urllib.request.urlopen('https://go.dev/ref/spec#Channel_types') ... PY(failed due to network proxy/tunnel restriction:403 Forbidden).- ✅
go test ./pkg/aggregator -tags test -run TestFlushIncludesPendingSamples -count=1 - ✅
go test ./pkg/aggregator -tags test -run TestFlushIncludesPendingSamples -count=10
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that solution seems a little too clever. if the channel is drained by something else we could end up getting locked, right? this proposed alternative change is okay now, but may be a surprising error in the future.
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This comment is wrong now :)
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not anymore! (reverted the time sampler worker changes and going with a different approach after @carlosroman 's feedback =] )
Need to make sure that the test actually fails in our ci. Then we can re-enable the fix.
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What does this PR do?
Drain samples on aggregator flush. This way samples that are submitted right at shutdown correctly get flushed.
Motivation
We noticed some metrics being missed in cloud run jobs at shutdown. The metrics get submitted correctly if we enable debug logging, adding time for the aggregator to fully drain.
Describe how you validated your changes
Unit test. Running the test without the fix in CI to confirm that it actually detects the problem. Also deployed to a real cloud run job which shows the issue without the fix and correctly submits metrics with the fix in place.