feat(web-analytics): roll no-join fast paths to all us cloud teams

[lricoy]

Problem

The no-join fast paths (#70746) rolled to 50% of US Cloud teams via deterministic team bucketing (#70906). Production evidence after 14 hours at 50%:

Metric	Pre-merge (join, eligible population, 24h)	Post-merge (no-join, 14h at 50%)
Paths tile p50	816ms	384ms (2.1x)
Paths tile p95	3.6s	815ms (4.4x)
Paths tile p99	7.3s	2.3s (3.2x)
Paths tile max memory	33.4 GiB	741 MiB (45x)
Overview max memory	21.9 GiB	196 MiB (114x)
Teams served	-	374 (674 paths servings + 100 overview)
Query-level fast-path failures	-	0 (only anomaly: one team's 1-second burst into the pre-existing 30-concurrent-queries OFFLINE cap)
Out-of-bucket servings	-	0

Coverage math: ~86% of user-facing web analytics queries reaching ClickHouse are unfiltered and therefore eligible; at 50% team bucketing roughly half of that population is served today, so this PR approximately doubles fast-path coverage to all eligible US traffic.

(Eligible population = user-facing, unfiltered, no test-account filtering - the class the fast path serves. The post p99 tail is bounded-memory queue contention on the dogfooding team, not query cost.)

Changes

One line: the US Cloud default for WEB_ANALYTICS_NO_JOIN_ROLLOUT_PERCENT goes 50 → 100. Every US team's unfiltered overview and paths queries take the fast path on deploy. EU stays at 0 (pending its ClickHouse 26.6 upgrade convergence + separate verification), self-hosted and tests unaffected. The env var remains a two-way override and the kill switch.

How did you test this code?

• Settings-only change; the bucketing/allowlist behavior is covered by TestWebOverviewNoJoinRolloutPercent (boundary-exact tests) from feat(web-analytics): percentage-of-teams rollout for no-join fast paths #70906.
• Production evidence above; monitoring continues via the stats_table_no_join_* / web_overview_no_join_query tags (feat(web-analytics): tag no-join overview executions with their own query type #70934) and web_analytics_no_join_served_total.

Automatic notifications

• Publish to changelog?
• Alert Sales and Marketing teams?

Docs update

No user-facing behavior change (results parity verified; latency improves).

🤖 Agent context

Autonomy: Human-driven (agent-assisted)

• Final notch of the staged rollout Lucas directed (team 2 → 50% → 100%), backed by the fleet evidence table above collected via query_log monitoring.
• Skills invoked: /evaluating-web-analytics-performance.

[trunk-io]

     

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[greptile-apps]

_{Reviews (1): Last reviewed commit: "feat(web-analytics): roll no-join fast p..." | Re-trigger Greptile}

[stamphog]

One-line rollout-percentage config bump backed by production evidence, with an existing kill switch and boundary tests; author has STRONG familiarity with this exact file.

• Author wrote 100% of the modified lines and has 12 merged PRs in these paths (familiarity STRONG).
• 👍 on the PR from chatgpt-codex-connector[bot], greptile-apps[bot], hex-security-app[bot].

Gate mechanics and policy version

Gate		Result
prerequisites	✓	all clear
deny-list	✓	no deny categories matched
size	✓	2L, 1F substantive — within ceiling
tier	✓	T1-agent / T1a-trivial (2L, 1F, single-area, feat)
stamphog 2.0.0b3		.stamphog/policy.yml @ b821150 · reviewed head d624f52

[github-actions]

🤖 CI report

✅ Playwright — all passed

All tests passed.

View test results →

ℹ️ ClickHouse migration SQL — 1 migration(s)

ClickHouse migration SQL per cloud environment

• unset
  • all

    CREATE OR REPLACE VIEW custom_metrics_test
        AS SELECT
            'ClickHouseCustomMetric_Test' AS name,
            map('instance', hostname()) AS labels,
            1 AS value,
            'Test to check that the metric endpoint is working' AS help,
            'gauge' AS type

    CREATE OR REPLACE VIEW custom_metrics
        AS SELECT * REPLACE (toFloat64(value) as value)
        FROM custom_metrics_test

• US, EU, DEV
  • events, shufflehog

    CREATE OR REPLACE VIEW custom_metrics_test
        AS SELECT
            'ClickHouseCustomMetric_Test' AS name,
            map('instance', hostname()) AS labels,
            1 AS value,
            'Test to check that the metric endpoint is working' AS help,
            'gauge' AS type

    CREATE OR REPLACE VIEW custom_metrics
        AS SELECT * REPLACE (toFloat64(value) as value)
        FROM custom_metrics_test

[deployment-status-posthog]

Deploy status

Environment	Status	Deployed At	Workflow
dev	✅ Deployed	2026-07-15 15:04 UTC	Run
prod-us	✅ Deployed	2026-07-15 15:30 UTC	Run
prod-eu	✅ Deployed	2026-07-15 15:30 UTC	Run