docs: add always-on performance pass to the PR review guide

[matt-aitken]

Summary

Adds a dedicated, always-on Performance section to the repo PR review guide (.claude/REVIEW.md), so every review weighs new work against table size, hot paths, and how deep or wide the data it walks can get.

It names the tables to treat as huge (the TaskRun family in Postgres, task_events_v1/v2 in ClickHouse), the hot paths that warrant extra scrutiny (trigger and batch trigger, dequeue, execution-snapshot writes, OTEL ingestion, trace and run-list reads), the deep and wide shapes that turn one run into a large tree or batch, and five named anti-patterns with severities: per-level re-scans, dropping the partition-pruning predicate, unbounded IN lists, sequential per-level round-trips, and losing the single-query fast path.

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ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Repository UI

Review profile: CHILL

Plan: Pro

Run ID: 9c89f281-1931-4147-bc60-0c4ddd08ef3d

📥 Commits

Reviewing files that changed from the base of the PR and between f163c89 and d8b90e6.

📒 Files selected for processing (1)

• .claude/REVIEW.md

📜 Recent review details

⏰ Context from checks skipped due to timeout. (1)

• GitHub Check: Analyze (javascript-typescript)

🔇 Additional comments (2)

.claude/REVIEW.md (2)

18-23: LGTM!

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24-55: 📐 Maintainability & Code Quality

Verify the schema facts behind the new performance rubric.

This section bakes in load-bearing claims about table size, ClickHouse partitioning/sort keys, and hot-path table lists. If any of those drift, the review rubric will misclassify future findings.

Run this read-only check to confirm the guidance still matches the repo’s schema/docs:

#!/bin/bash
set -euo pipefail
rg -n --context 2 'model (TaskRun|TaskRunExecutionSnapshot|Waitpoint|BatchTaskRun)|@@index|task_events_v1|task_events_v2|ORDER BY|PARTITION BY|toDate\(inserted_at\)|toUnixTimestamp\(start_time\)|span_id|parent_span_id|MAXIMUM_TRACE_SUMMARY_VIEW_COUNT' .

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Walkthrough

.claude/REVIEW.md updates the Performance guidance by restating the opening performance-risk bullets and expanding the section with repo-specific rules for large tables, hot execution and read paths, deep or wide data shapes, and several explicit query anti-patterns with severity labels.

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Description check	⚠️ Warning	The description only includes a summary and omits the template's required issue, checklist, testing, changelog, and screenshots sections.	Add the Closes # line and fill in the checklist, Testing, Changelog, and Screenshots sections per the repository template.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly and accurately summarizes the change to the review guide.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

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✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch matt/review-guide-performance-pass

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