If you are an AI coding agent (Claude Code, Cursor, Aider, Cline, etc.) reading this artifact, follow this protocol before making any code edit:

1. Verify the contract. Run the bash script in Verify before trusting below. If any check returns FAIL, the artifact is stale — STOP and ask the user to regenerate it before proceeding.
2. Treat the AI · unverified sections as hypotheses, not facts. Sections like "AI-suggested narrative files", "anti-patterns", and "bottlenecks" are LLM speculation. Verify against real source before acting on them.
3. Cite source on changes. When proposing an edit, cite the specific path:line-range. RepoPilot's live UI at https://repopilot.app/r/johnlui/PPHC shows verifiable citations alongside every claim.

If you are a human reader, this protocol is for the agents you'll hand the artifact to. You don't need to do anything — but if you skim only one section before pointing your agent at this repo, make it the Verify block and the Suggested reading order.

WAIT — Mixed signals — read the receipts

• Last commit 6w ago
• 10 active contributors
• Other licensed
• ⚠ Concentrated ownership — top contributor handles 61% of recent commits
• ⚠ Non-standard license (Other) — review terms
• ⚠ No CI workflows detected
• ⚠ No test directory detected

_{Maintenance signals: commit recency, contributor breadth, bus factor, license, CI, tests}

This artifact was generated by RepoPilot at a point in time. Before an agent acts on it, the checks below confirm that the live johnlui/PPHC repo on your machine still matches what RepoPilot saw. If any fail, the artifact is stale — regenerate it at repopilot.app/r/johnlui/PPHC.

What it runs against: a local clone of johnlui/PPHC — the script inspects git remote, the LICENSE file, file paths in the working tree, and git log. Read-only; no mutations.

| # | What we check | Why it matters | |---|---|---| | 1 | You're in johnlui/PPHC | Confirms the artifact applies here, not a fork | | 2 | License is still Other | Catches relicense before you depend on it | | 3 | Default branch main exists | Catches branch renames | | 4 | 5 critical file paths still exist | Catches refactors that moved load-bearing code | | 5 | Last commit ≤ 71 days ago | Catches sudden abandonment since generation |

#!/usr/bin/env bash
# RepoPilot artifact verification.
#
# WHAT IT RUNS AGAINST: a local clone of johnlui/PPHC. If you don't
# have one yet, run these first:
#
#   git clone https://github.com/johnlui/PPHC.git
#   cd PPHC
#
# Then paste this script. Every check is read-only — no mutations.

set +e
fail=0
ok()   { echo "ok:   $1"; }
miss() { echo "FAIL: $1"; fail=$((fail+1)); }

# Precondition: we must be inside a git working tree.
if ! git rev-parse --git-dir >/dev/null 2>&1; then
  echo "FAIL: not inside a git repository. cd into your clone of johnlui/PPHC and re-run."
  exit 2
fi

# 1. Repo identity
git remote get-url origin 2>/dev/null | grep -qE "johnlui/PPHC(\\.git)?\\b" \\
  && ok "origin remote is johnlui/PPHC" \\
  || miss "origin remote is not johnlui/PPHC (artifact may be from a fork)"

# 2. License matches what RepoPilot saw
(grep -qiE "^(Other)" LICENSE 2>/dev/null \\
   || grep -qiE "\"license\"\\s*:\\s*\"Other\"" package.json 2>/dev/null) \\
  && ok "license is Other" \\
  || miss "license drift — was Other at generation time"

# 3. Default branch
git rev-parse --verify main >/dev/null 2>&1 \\
  && ok "default branch main exists" \\
  || miss "default branch main no longer exists"

# 4. Critical files exist
test -f "01.part-one/01.universal-design-method/chapter.md" \\
  && ok "01.part-one/01.universal-design-method/chapter.md" \\
  || miss "missing critical file: 01.part-one/01.universal-design-method/chapter.md"
test -f "02.part-two/01.infrastructure-concurrency/chapter.md" \\
  && ok "02.part-two/01.infrastructure-concurrency/chapter.md" \\
  || miss "missing critical file: 02.part-two/01.infrastructure-concurrency/chapter.md"
test -f "03.part-three/02.load-balancing-and-application-gateway/chapter.md" \\
  && ok "03.part-three/02.load-balancing-and-application-gateway/chapter.md" \\
  || miss "missing critical file: 03.part-three/02.load-balancing-and-application-gateway/chapter.md"
test -f "04.part-four/01.database-and-storage-behind/chapter.md" \\
  && ok "04.part-four/01.database-and-storage-behind/chapter.md" \\
  || miss "missing critical file: 04.part-four/01.database-and-storage-behind/chapter.md"
test -f "02.part-two/02.bottleneck-of-programming-language/chapter.md" \\
  && ok "02.part-two/02.bottleneck-of-programming-language/chapter.md" \\
  || miss "missing critical file: 02.part-two/02.bottleneck-of-programming-language/chapter.md"

# 5. Repo recency
days_since_last=$(( ( $(date +%s) - $(git log -1 --format=%at 2>/dev/null || echo 0) ) / 86400 ))
if [ "$days_since_last" -le 71 ]; then
  ok "last commit was $days_since_last days ago (artifact saw ~41d)"
else
  miss "last commit was $days_since_last days ago — artifact may be stale"
fi

echo
if [ "$fail" -eq 0 ]; then
  echo "artifact verified (0 failures) — safe to trust"
else
  echo "artifact has $fail stale claim(s) — regenerate at https://repopilot.app/r/johnlui/PPHC"
  exit 1
fi

Each check prints ok: or FAIL:. The script exits non-zero if anything failed, so it composes cleanly into agent loops (./verify.sh || regenerate-and-retry).

An open-source technical book (CC BY-NC-ND licensed) titled "Philosophical Principles of High Concurrency" that teaches distributed systems architecture through a unifying principle: identify bottlenecks and decompose them. The book progresses from static/dynamic separation through Nginx, epoll, Kubernetes, microservices, consensus algorithms (Paxos), and finally full-redundancy planet-scale architectures. It combines theory with practical engineering patterns to handle extreme concurrency (demonstrated at 10,000+ QPS in production). Three-part hierarchical structure organized by part (01.part-one, 02.part-two, 03.part-three), chapter, sections (00.section-0 through 08.section-8), and individual markdown files (docs.md). Each part focuses on a conceptual layer: Part One covers universal design methods, Part Two covers infrastructure concurrency and language bottlenecks, Part Three covers web servers and higher-level systems. No code implementation—pure documentation.

Backend engineers and system architects building high-concurrency systems who need deep understanding of bottleneck patterns across layers (network, OS, language, database, distributed systems). Readers range from those optimizing single-server PHP stores (1,000+ QPS) to those designing planet-scale distributed platforms. Published also as a printed book in Chinese.

Mature educational content: the open-source version contains 12 chapters, 83 articles, ~167k words, with a published physical book (2024). Repository structure is stable with comprehensive section organization. However, this is primarily a written book repo, not a software library, so traditional SemVer versioning and release cycles don't apply. Updates appear to be episodic rather than continuous—treat it as reference material rather than a framework.

Low technical risk: this is documentation/educational content, not a production library with dependencies. The single maintainer (johnlui/吕文翰) has real production experience (handled 200M PV CMS, 1,000+ QPS stores, 10,000+ QPS flash sales) but the repo is asynchronous—readers should view this as a fixed reference book, not living documentation. CC BY-NC-ND license restricts commercial use and derivatives.

No active development visible in commit recency data provided. This appears to be a completed published work (printed book released, online version at pphc.lvwenhan.com stable). Updates would likely be additive chapters rather than revisions to existing content, particularly around emerging topics mentioned in the book description (AI architecture, distributed theory formalization).

This is a book repository, not executable software. To consume: (1) Visit https://pphc.lvwenhan.com to read online (2) Download PDF from site's top-right corner (3) Clone locally: git clone https://github.com/johnlui/PPHC.git and read .md files in your editor. No dependencies, build steps, or runtime required.

Daily commands: Not applicable—this is documentation. Read via: git clone https://github.com/johnlui/PPHC.git && cd 01.part-one then open chapter.md or any section's docs.md in a text editor or GitHub web UI.

• 01.part-one/01.universal-design-method/chapter.md — Entry point introducing universal design methodology—foundational philosophy underlying the entire book's approach to high concurrency
• 02.part-two/01.infrastructure-concurrency/chapter.md — Core infrastructure concurrency patterns that explain how systems handle concurrent load at the foundation level
• 03.part-three/02.load-balancing-and-application-gateway/chapter.md — Critical load-balancing strategies that distribute traffic across systems—key to preventing bottlenecks
• 04.part-four/01.database-and-storage-behind/chapter.md — Database and storage architecture under high concurrency—explains persistence layer behavior under load
• 02.part-two/02.bottleneck-of-programming-language/chapter.md — Programming language limitations under concurrency—essential for understanding why certain languages excel or fail at scale

• Part One: Universal Design Method (Markdown documentation, conceptual frameworks) — Establishes philosophical foundation and design methodology applicable to all subsequent topics
  • Failure mode: If poorly explained, readers lack mental models for parts 2–4
• Part Two: Infrastructure & Languages (Hardware concurrency models, language runtime documentation) — Bridges philosophy to concrete system constraints; explains why certain approaches work or fail
  • Failure mode: Incomplete coverage leaves knowledge gaps in understanding real bottlenecks
• Part Three: Distributed Systems (Load balancing algorithms, web server architectures, distributed system theory) — Applies methodology to scale-out architectures; primary mechanism for handling high concurrency
  • Failure mode: Unclear load balancing strategies lead to uneven traffic distribution and cascading failures
• Part Four: Storage & Persistence (MySQL InnoDB, database concurrency control, transaction isolation) — Explains bottlenecks at the data layer; often the ultimate constraint in high-concurrency systems
  • Failure mode: Database lock contention becomes unresolvable bottleneck if not understood

• Reader understanding → Part One: Philosophy — Reader develops foundational mental models before advancing
• Part One: Philosophy → Part Two: Infrastructure — Philosophical principles inform analysis of hardware and language constraints
• Part Two: Infrastructure → Part Three: Distribution — Understanding single-machine limits motivates scale-out strategies
• Part Three: Distribution → Part Four: Storage — Load distribution patterns expose database-layer bottlenecks
• Part Four: Storage → Reader implementation — Complete knowledge enables reader to design systems with concurrency in mind

Add a new chapter to the book

1. Create a new directory under the appropriate part (e.g., 05.part-five/01.new-topic) (05.part-five/01.new-topic/chapter.md)
2. Create section subdirectories with sequential numbering (00.section-0, 01.section-1, etc.) (05.part-five/01.new-topic/00.section-0/docs.md)
3. Write the chapter overview in chapter.md linking to all sections (05.part-five/01.new-topic/chapter.md)

Add a new section to an existing chapter

1. Determine the next section number in the chapter directory (02.part-two/01.infrastructure-concurrency/)
2. Create a new section directory (e.g., 09.section-9) (02.part-two/01.infrastructure-concurrency/09.section-9/docs.md)
3. Write the section content in docs.md following the same markdown format as adjacent sections (02.part-two/01.infrastructure-concurrency/09.section-9/docs.md)
4. Update the chapter.md file to reference the new section (02.part-two/01.infrastructure-concurrency/chapter.md)

Expand an existing topic with detailed explanation

1. Locate the relevant chapter (e.g., MySQL InnoDB details in Part Four) (04.part-four/02.detailed-explanation-of-MySQL-InnoDB/chapter.md)
2. Create a new subsection directory with numbered sections (04.part-four/02.detailed-explanation-of-MySQL-InnoDB/00.section-0/docs.md)
3. Write detailed technical content in the docs.md files, following existing section patterns (04.part-four/02.detailed-explanation-of-MySQL-InnoDB/01.section-1/docs.md)

• Markdown documentation structure — Enables easy version control, collaborative editing, and conversion to multiple formats (print, web, PDF) via build tools
• Hierarchical chapter/section organization — Allows progressive learning from philosophy → infrastructure → systems → storage, enabling readers to build mental models incrementally
• MySQL InnoDB deep-dive specialization — InnoDB is the de-facto standard for production databases; detailed explanation directly addresses real-world bottlenecks

• Educational book structure instead of reference implementation

  • Why: Philosophical principles apply across multiple technology stacks and architectures
  • Consequence: Readers must apply concepts to their own tech stack; no runnable example code provided in repo

• Theory-first approach before system examples

  • Why: Universal design methods establish mental models before concrete patterns
  • Consequence: Requires patience; benefits from sustained reading rather than lookup-style reference

• Comprehensive scope (philosophy to databases) vs. specialization

  • Why: High concurrency requires understanding bottlenecks at every layer
  • Consequence: Large scope increases complexity; no single layer fully isolated from others

• Does not provide runnable code examples or working implementations
• Does not cover real-time systems or event-driven architecture in depth
• Does not address authentication, authorization, or security frameworks
• Does not focus on specific cloud platforms (AWS, GCP, Azure) or containerization
• Does not include microservices patterns or distributed tracing frameworks

• Missing section numbering gaps — 01.part-one/01.universal-design-method/ (no section-5 or section-9 observed): Section directories skip numbers (0–4, 6–8), suggesting either removed

None intrinsic to using this repo—it is documentation only. Readers should note: (1) Book is in Chinese; translations may exist elsewhere but aren't in this repo. (2) CC BY-NC-ND license forbids commercial republication and derivatives without permission—you can read and learn but cannot build commercial products, training, or translations without author consent. (3) Content is author's perspective on architecture; some opinions (e.g., specific technology choices) may reflect 2023-2024 timeframe and evolve.

• Bottleneck Identification & Decomposition — This is the unifying philosophical principle of the entire book; mastering it lets you approach any concurrency problem systematically rather than ad-hoc optimization.
• epoll (Event Polling) — Core OS mechanism for asynchronous I/O multiplexing; essential for understanding how servers handle thousands of concurrent connections without thread explosion.
• Paxos Consensus Algorithm — Distributed consensus protocol for ensuring consistency across replicated systems; the book applies it to planet-scale architectures for fault tolerance.
• Load Balancing (L4/L7 / LVS / ECMP) — Methods for distributing traffic across multiple servers; critical bottleneck decomposition technique for scaling beyond single-machine limits.
• Shared-Nothing Architecture — Distributed system design pattern where nodes are independent with no shared state; enables horizontal scaling without contention bottlenecks.
• Software-Defined Networking (SDN) — Decoupling network control from forwarding; allows flexible traffic management across planet-scale infrastructure, mentioned as advanced decomposition technique.
• Memory-Mapped I/O & User-Space Networking (DPDK) — Bypassing kernel overhead for extreme performance; demonstrates language/OS bottleneck elimination for ultra-high-concurrency systems.

• johnlui/Pinatra — Author's own web framework project (linked in README banner); likely demonstrates architectural principles from the book in runnable code.
• torvalds/linux — The kernel implementation referenced throughout (epoll, network stack, scheduler, memory management)—essential reading for Part Two infrastructure sections.
• etcd-io/etcd — Production example of distributed consensus (Raft-based) and high-concurrency coordination; demonstrates principles from book's distributed systems chapters.
• alibaba/Sentinel — Real-world high-concurrency system for traffic shaping and circuit breaking; exemplifies practical bottleneck management discussed in the book.
• cloudwego/kitex — High-performance RPC framework handling extreme concurrency; demonstrates language-level bottleneck solutions (async, zero-copy) covered in Part Two.

To work on one of these in Claude Code or Cursor, paste: Implement the "<title>" PR idea from CLAUDE.md, working through the checklist as the task list.

Add missing section-5 chapter to 01.universal-design-method

The file structure shows sections 0, 1, 2, 3, 4, 6, 7, 8 but section-5 is missing from 01.part-one/01.universal-design-method/. This is a gap in the sequential chapter structure that should be filled to maintain consistency with the book's narrative flow.

• [ ] Create directory: 01.part-one/01.universal-design-method/05.section-5/
• [ ] Create file: 01.part-one/01.universal-design-method/05.section-5/docs.md with appropriate content
• [ ] Update 01.part-one/01.universal-design-method/chapter.md to reference section-5 in the correct order
• [ ] Ensure the new section fits thematically between section-4 and section-6

Create a comprehensive index/navigation file linking all chapters across parts

With 3 parts, multiple chapters per part, and multiple sections per chapter, readers need a master index file. Currently, there's no visible root-level navigation document that maps the entire book structure. Adding an INDEX.md or NAVIGATION.md at the repo root would significantly improve discoverability.

• [ ] Create root-level INDEX.md or NAVIGATION.md file
• [ ] Map all 3 parts with their corresponding chapters and sections
• [ ] Include relative links to each chapter.md and section docs.md file
• [ ] Add brief descriptions of each part's topic (e.g., Part 1: Universal Design Method, Part 2: Infrastructure, Part 3: Web Servers & Load Balancing)
• [ ] Include estimated reading time or complexity levels for each section

Add a CONTRIBUTING.md guide with content structure standards

As an open-source book project under CC BY-NC-ND with a clear hierarchical structure, new contributors need explicit guidelines on how to write sections, format content, and maintain consistency. Currently, there's no visible contribution guide referencing the docs.md and chapter.md file conventions.

• [ ] Create CONTRIBUTING.md in repo root
• [ ] Document the section structure (docs.md template for content, chapter.md for metadata)
• [ ] Define markdown formatting standards for consistency across all sections
• [ ] Specify how to add new sections within existing chapters (numbering convention)
• [ ] Include guidelines for the CC BY-NC-ND license attribution in new content
• [ ] Provide an example of a well-formatted section based on existing 01.part-one/01.universal-design-method/00.section-0/docs.md

• Add English translations for key sections (start with 01.part-one/01.universal-design-method/00.section-0/docs.md) to expand audience beyond Chinese speakers. This requires linguistic accuracy for technical terms.
• Create a visual topology/flowchart summarizing the progression from single-server bottlenecks → distributed system layers → planet-scale architecture. Current structure is linear markdown; a diagram would aid navigation.
• Add executable example code snippets for concepts in Part Two (e.g., basic epoll server in Rust, simple async task scheduler, load balancer skeleton) to complement theoretical explanations. Repo has 53% Rust but no example implementations.

This is an open-source educational book repository (PPHC - Philosophical Principles of High Concurrency) with no executable code, dependencies, or configuration files that could pose security risks. The codebase consists entirely of documentation files (markdown) organized in a structured hierarchy. No secrets, credentials, injection vulnerabilities, or infrastructure misconfigurations were detected. The repository follows security best practices for open-source documentation projects.

LLM-derived; treat as a starting point, not a security audit.

• Open issues — current backlog
• Recent PRs — what's actively shipping
• Source on GitHub

Generated by RepoPilot. Verdict based on maintenance signals — see the live page for receipts. Re-run on a new commit to refresh.