Lecture
Deep Lecture
Chinese system explanation plus English recall assets and Bad/Good/Great ladders.
Week 8 · Sep 14-20, 2026 · Reliable execution
Web Crawler + Job Scheduler + Price Tracking Transfer
A complete Week 8 study week: frontier ownership, politeness, leases, retries, dedupe, change detection, restart-safe workflows, and 21 contiguous Heap/Priority Queue slots.
CORE: Web CrawlerCORE: Job SchedulerTRANSFER: Price TrackingDDIA Ch5/Ch9/Ch12 only
Daily Plan
Week 4 pattern preserved: precise anchors, exact time blocks, focused DDIA decision sections, and artifact-first evidence.
Day 1
Mon Sep 14, 2026
Web Crawler CORE HLD
A frontier-owned crawler design with explicit visited state, raw/object storage, parse/index stages, and durable restart points.
Day 2
Tue Sep 15, 2026
Web Crawler CORE Deep Dives
A Staff-level crawler answer for frontier leases, retry/DLQ, robots, per-domain pacing, dedupe, and 10B-page throughput.
Day 3
Wed Sep 16, 2026
Job Scheduler CORE HLD
A scheduler HLD that separates job definitions, schedules, execution instances, leases, attempts, and user-visible status.
Day 4
Thu Sep 17, 2026
Job Scheduler CORE Deep Dives
A Staff scheduler answer with time buckets, near-term delay queues, leases, zombie fencing, retries, backoff, poison queues, idempotent handlers, and exactly-once illusion.
Day 5
Fri Sep 18, 2026
Price Tracking Service TRANSFER
A blind-first transfer artifact with deltas, invalid assumptions, new bottleneck, follow-up, and direct links to every Price Tracking heading.
Day 6
Sat Sep 19, 2026
Two 45-minute Adaptive Mocks
Independent adaptive mocks for Web Crawler and Job Scheduler, plus a transfer pressure drill for Price Tracking.
Day 7
Sun Sep 20, 2026
Repair, Synthesis, Scorecard
A final scorecard with artifact proof, heading coverage, DDIA decisions, Heap evidence, and a READY_FOR_REVIEW production record.
Artifacts
Core and transfer deliverables are local, printable, and linked from daily pages.
Artifact
Web Crawler CN lecture
web-crawler-complete-zh-script.md
web-crawler-complete-zh-audio.mp3
Artifact
Web Crawler EN recall
web-crawler-senior-staff-recall-script.md
web-crawler-senior-staff-recall-script.pdf
Artifact
Job Scheduler CN lecture
job-scheduler-complete-zh-script.md
job-scheduler-complete-zh-audio.mp3
Artifact
Job Scheduler EN recall
job-scheduler-senior-staff-recall-script.md
job-scheduler-senior-staff-recall-script.pdf
Artifact
Price Tracking transfer
price-tracking-transfer-script.md
price-tracking-transfer-audio.mp3
Practice Tools
Use these after the day pages. They are scoped to Week 8 only.
Canonical Heading Inventory
Direct external anchors are inventoried here and assigned to precise day pages.
| Source | Canonical heading | Day | Disposition |
|---|---|---|---|
| Web Crawler | Understanding the Problem | Day 1 | CORE scope and requirements gate |
| Web Crawler | Functional Requirements | Day 1 | CORE functional contract |
| Web Crawler | Non-Functional Requirements | Day 1 | CORE scale, availability, politeness constraints |
| Web Crawler | The Set Up | Day 1 | CORE setup and interviewer framing |
| Web Crawler | Planning the Approach | Day 1 | CORE planning spine |
| Web Crawler | API or System Interface | Day 1 | CORE crawl submission and status surface |
| Web Crawler | Data Flow | Day 1 | CORE fetch/extract/index/event flow |
| Web Crawler | High-Level Design | Day 1 | CORE architecture |
| Web Crawler | Potential Deep Dives | Day 2 | CORE deep-dive index |
| Web Crawler | 1) How can we ensure we are fault tolerant and don't lose progress? | Day 2 | CORE restart-safe frontier and durable progress |
| Web Crawler | 2) How can we ensure politeness and adhere to robots.txt? | Day 2 | CORE per-domain politeness and robots enforcement |
| Web Crawler | 3) How to scale to 10B pages and efficiently crawl them in under 5 days? | Day 2 | CORE partitioning, batching, and throughput |
| Web Crawler | Some additional deep dives you might consider | Day 2 | CORE optional pressure prompts |
| Web Crawler | What is Expected at Each Level? | Day 6 | Mock rubric calibration |
| Web Crawler | Mid-level | Day 6 | Rubric contrast |
| Web Crawler | Senior | Day 6 | Senior+ bar |
| Web Crawler | Staff+ | Day 6 | Staff bar |
| Job Scheduler | Understanding the Problem | Day 3 | CORE scope and requirements gate |
| Job Scheduler | Functional Requirements | Day 3 | CORE schedule, monitor, cancel contract |
| Job Scheduler | Non-Functional Requirements | Day 3 | CORE precision, scale, durability constraints |
| Job Scheduler | The Set Up | Day 3 | CORE setup and interviewer framing |
| Job Scheduler | Planning the Approach | Day 3 | CORE planning spine |
| Job Scheduler | Defining the Core Entities | Day 3 | Job, schedule, execution, attempt, lease |
| Job Scheduler | The API | Day 3 | CORE API |
| Job Scheduler | Data Flow | Day 3 | CORE write, schedule, dispatch, execute, observe flow |
| Job Scheduler | High-Level Design | Day 3 | CORE architecture |
| Job Scheduler | 1) Users should be able to schedule jobs to be executed immediately, at a future date, or on a recurring schedule | Day 3 | CORE scheduling flow |
| Job Scheduler | 2) Users should be able monitor the status of their jobs. | Day 3 | CORE observability surface |
| Job Scheduler | Potential Deep Dives | Day 4 | CORE deep-dive index |
| Job Scheduler | 1) How can we ensure the system executes jobs within 2s of their scheduled time? | Day 4 | CORE two-layer scheduling and timing precision |
| Job Scheduler | 2) How can we ensure the system is scalable to support up to 10k jobs per second? | Day 4 | CORE throughput partitioning |
| Job Scheduler | 3) How can we ensure at-least-once execution of jobs? | Day 4 | CORE leases, retries, poison messages, idempotence |
| Job Scheduler | What is Expected at Each Level? | Day 6 | Mock rubric calibration |
| Job Scheduler | Mid-level | Day 6 | Rubric contrast |
| Job Scheduler | Senior | Day 6 | Senior+ bar |
| Job Scheduler | Staff+ | Day 6 | Staff bar |
| Price Tracking Service | Understanding the Problem | Day 5 | TRANSFER blind scope check |
| Price Tracking Service | Functional Requirements | Day 5 | TRANSFER requirements |
| Price Tracking Service | Non-Functional Requirements | Day 5 | TRANSFER scale and latency constraints |
| Price Tracking Service | The Set Up | Day 5 | TRANSFER setup |
| Price Tracking Service | Planning the Approach | Day 5 | TRANSFER planning |
| Price Tracking Service | Defining the Core Entities | Day 5 | Product, price sample, subscription, alert |
| Price Tracking Service | The API | Day 5 | TRANSFER API |
| Price Tracking Service | Data Flow | Day 5 | TRANSFER scrape/sample/notify flow |
| Price Tracking Service | High-Level Design | Day 5 | TRANSFER architecture |
| Price Tracking Service | 1) Users should be able to view price history for Amazon products (via website or Chrome extension) | Day 5 | TRANSFER price history surface |
| Price Tracking Service | 2) Users should be able to subscribe to price drop notifications with thresholds (via website or Chrome extension) | Day 5 | TRANSFER notification contract |
| Price Tracking Service | Potential Deep Dives | Day 5 | TRANSFER deep-dive index |
| Price Tracking Service | 1) How do we efficiently discover and track 500 million Amazon products? | Day 5 | TRANSFER discovery scale |
| Price Tracking Service | 2) How do we handle potentially malicious price updates from Chrome extension users? | Day 5 | TRANSFER trust boundary |
| Price Tracking Service | 3) How do we efficiently process price changes and notify subscribed users? | Day 5 | TRANSFER change detection and fanout |
| Price Tracking Service | 4) How do we serve fast price history queries for chart generation? | Day 5 | TRANSFER query serving |
| Price Tracking Service | Final Design | Day 5 | TRANSFER final synthesis |
| Price Tracking Service | What is Expected at Each Level? | Day 6 | Transfer rubric calibration |
| Price Tracking Service | Mid-level | Day 6 | Rubric contrast |
| Price Tracking Service | Senior | Day 6 | Senior+ bar |
| Price Tracking Service | Staff+ | Day 6 | Staff transfer bar |
DDIA Exact Sections
No other DDIA sections are required for Week 8 production.
| Chapter | Exact section | Use |
|---|---|---|
| Ch5 | 数据流的模式 | Week 8 decision section only |
| Ch5 | 持久化执行与工作流 | Week 8 decision section only |
| Ch5 | 持久化执行 | Week 8 decision section only |
| Ch5 | 事件驱动的架构 | Week 8 decision section only |
| Ch5 | 消息代理 | Week 8 decision section only |
| Ch9 | 故障与部分失效 | Week 8 decision section only |
| Ch9 | 超时和无界延迟 | Week 8 decision section only |
| Ch9 | 进程暂停 | Week 8 decision section only |
| Ch9 | 分布式锁和租约 | Week 8 decision section only |
| Ch9 | 隔离僵尸进程和延迟请求 | Week 8 decision section only |
| Ch9 | 故障注入 | Week 8 decision section only |
| Ch12 | 消息传递系统 | Week 8 decision section only |
| Ch12 | 确认应答与重新传递 | Week 8 decision section only |
| Ch12 | 基于日志的消息代理 | Week 8 decision section only |
| Ch12 | 日志与传统的消息传递相比 | Week 8 decision section only |
| Ch12 | 消费者偏移量 | Week 8 decision section only |
| Ch12 | 重播旧消息 | Week 8 decision section only |
| Ch12 | 变更数据捕获 | Week 8 decision section only |
| Ch12 | 日志压缩 | Week 8 decision section only |
| Ch12 | 容错 | Week 8 decision section only |
| Ch12 | 幂等性 | Week 8 decision section only |
| Ch12 | 失败后重建状态 | Week 8 decision section only |
Detailed lecture notes, audio, recall scripts, PDFs, Staff Q&A, and mock packs are archived locally and are intentionally not published on this site.