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Wiki Operation Log

Wiki Operation Log

Append-only. Each entry format: ## [YYYY-MM-DD] action | description

Parse last 5 entries: grep "^## \[" log.md | tail -5

Actions: init | ingest | query | lint | synthesis | update

[2026-04-16] gap-fill | 16 missing pages created across 6 domains

Go (3 new): Context, HTTP Server, Testing DSA (3 new): Merge Intervals, Prefix Sum, Bit Manipulation System Design (3 new): Caching & Redis, Message Queues & Kafka, Consistent Hashing Python (3 new): Asyncio, FastAPI, Pydantic AWS (3 new): RDS, SQS & SNS, CloudWatch FrontEnd (1 new): TypeScript Updated: Go Topics, Python Topics, AWS Topics, FrontEnd Topics, index.md (124 pages)

Remaining gaps still open:

  • Go: sync.Pool/atomic, profiling/pprof, stdlib cheatsheet
  • DSA: Cyclic Sort, Fast & Slow Pointers dedicated page
  • System Design: YouTube/Netflix, Twitter Feed, WhatsApp, Google Docs, Hotstar, Maps/LBS
  • Python: pytest, dataclasses, context managers, type hints
  • AWS: DynamoDB, ElastiCache, API Gateway (AWS), ECS/EKS
  • AI/ML: LLM Fundamentals, Vector DBs, LangGraph

[2026-04-17] update | Weekly tracker created, old plan replaced, backlinks updated

  • Replaced Job Switch Plan 2026 (old 5-track plan) with revised single-focus plan
  • Created Weekly Progress Tracker (W06–W26) with milestones per week
  • Backlinks updated: DSA Topics, FrontEnd Topics, System Design Basics
  • Index updated: 133 pages, page_count corrected

[2026-04-17] gap-fill | 9 missing pages added (index: 124 → 133)

New pages:

  • DSA/SQL for Interviews — JOINs, window fns, CTEs, indexes, ACID, N+1, practice track
  • System Design/API Design Principles — REST, idempotency, pagination, versioning, status codes
  • System Design/Low Level Design — SOLID, 5 machine coding problems (LRU, rate limiter, parking lot, Splitwise, event emitter)
  • System Design/Docker and Kubernetes — conceptual reference, Dockerfile, K8s objects
  • System Design/Problem Designs/YouTube — transcoding pipeline, CDN, adaptive bitrate
  • System Design/Problem Designs/Twitter Feed — fan-out strategies, Snowflake IDs, Cassandra
  • System Design/Problem Designs/WhatsApp — WebSocket routing, message ordering, E2E encryption
  • System Design/Problem Designs/Google Docs — OT vs CRDT, collaborative editing deep dive
  • FrontEnd/Frontend System Design — typeahead, infinite scroll, real-time dashboard, state mgmt

[2026-04-17] update | DSA + SD progress reset to accurate state

DSA: Arrays & Hashing ✅, Two Pointers ✅, Sliding Window ✅, Binary Search ✅ — rest ⬜ SD: All 10 problems reset to ⬜ (interview-level bar: whiteboard in 45 min cold, not just read notes) Updated: Job Switch Hub, Interview Prep Hub

[2026-04-27] update | Vault-wide structural fixes (8 issues)

  • CLAUDE.md: SQL/ added to both directory tables, AWS description updated (MLA-C01 removed)
  • SQL/SQL Topics.md: index page created with practice tracker + concept checklist
  • CLAUDE.original.md: deleted (compress leftover)
  • Tech Stack Overview: AWS cert references removed, Bedrock production use noted
  • 2026 Goals: MLA-C01 → deferred, vectorbuilds.dev → deferred, learning section updated to new plan
  • Interview Prep Hub: DSA/SQL/LLD statuses updated to current state
  • index.md: page_count updated to 118, last_updated 2026-04-27
  • SQL for Interviews: practice tracker + concept checklist added

[2026-04-26] update | Weekly tracker cleanup + W05–W13 created (restart after Apr 13–26 break)

  • W01–W04 individual files deleted, consolidated into W01-W04 Archive (Mar 18–Apr 12).md
  • Created: W05 (Apr 27–May 3) with full daily plan, W06–W13 with track plans + metrics
  • Updated: Weekly Progress Tracker (phases rebased to W05 start Apr 27), Job Switch Hub (current state)
  • W05 focus: Linked Lists + URL Shortener (interview-ready) + SQL start
  • Apply sprint unchanged: first applications Jun 1 (W10)

[2026-04-17] update | Prep plan + synthesis pages overhauled post career-clarity session

Updated: synthesis/Job Switch Hub.md, synthesis/Interview Prep Hub.md

Key changes:

  • Honest profile assessment added (what he actually built vs claimed)
  • Prep priority revised: 7 core topics + 5 for full-stack (not 15 parallel tracks)
  • Apply date moved up: Jun 1 not Jul 18 (AI startups first)
  • Job links added: Sarvam AI (4 live postings), Razorpay, PhonePe, CRED, BrowserStack, Zepto, Swiggy, Juspay
  • SQL section added to Interview Prep Hub (fintech companies test this — was missing)
  • LLD/Machine Coding moved up to W06 (was W10-W11 — too late)
  • FastAPI internals section added with code patterns
  • API Design principles section added
  • AskTGE designated as primary interview story everywhere
  • Backend project added as explicit milestone (closes architecture credibility gap)
  • Dropped: AWS MLA-C01 cert, Go mastery track, blog — all post-offer

[2026-04-17] update | Resume rewritten — accuracy pass + AskTGE added

Saved to: Private/Resume/Resume_2026.tex

Key changes from original:

  • Headline: "full-stack + distributed systems" → "backend systems + real-time + AI integrations"
  • AskTGE LLM optimization added as first HCLTech bullet (was missing entirely)
    • DynamoDB schema redesign + API latency 2s → 200ms + hallucination fixes + summarization
  • WebSocket bullet reframed: "Engineered geospatial engine" → "Built driver tracking FE + FastAPI initial load"
  • ML Thresholding: "Architected and deployed" → "Implemented parallel processing + per-KPI failure isolation"
  • Skills cleanup: removed Vue.js, D3.js, UI/UX Design, C++, Deep Learning, Pandas, Node.js
  • Skills added: DynamoDB, WebSockets, LangChain, RAG Pipelines, PostgreSQL

[2026-04-16] init | Karpathy wiki architecture implemented

Bootstrapped wiki infrastructure:

  • Added three-layer architecture (raw sources / wiki / schema)
  • Created raw/ for immutable source documents
  • Created synthesis/ for cross-domain LLM-maintained pages
  • Created index.md — full wiki catalog (108 pages)
  • Created log.md — this file
  • Created Uncategorized/ directory (was referenced but missing)
  • Updated CLAUDE.md with ingest/query/lint workflows
  • Created 5 synthesis pages:
    • synthesis/Job Switch Hub.md — 50+ LPA goal tracking
    • synthesis/Interview Prep Hub.md — aggregated interview prep
    • synthesis/Tech Stack Overview.md — positioning guide
    • synthesis/Concurrency Deep Dive.md — Go + Python + distributed
    • synthesis/LLM & AI Stack.md — AI company targeting

[2026-04-27] update | SQL resource sync + Binary Search W04 status

  • synthesis/Interview Prep Hub.md — SQL Practice section: HackerRank → DataLemur + LeetCode SQL 50 (matches SQL for Interviews.md)
  • Private/Project_2026/Weekly Tracker/Week 05.md — all HackerRank SQL refs → DataLemur Easy + LeetCode SQL 50
  • DSA/DSA Techniques for Interviews/Binary Search.md — marked LC 704, 74, 153, 33, 981, 875 as ✅ W04; LC 4 (Median of Two Sorted Arrays) as ⬜ Deferred

[2026-04-27] ingest | The Day a Google L7 Engineer Tore My System Design to Shreds

Source: Medium / Cloud With Azeem — L7 system design interview lessons via URL shortener war story

Pages created:

  • System Design/Senior SD Mindset.md — Pattern Trap, Hot Key problem, cache hit rate formula, failure-first thinking, trade-offs, prep methodology

Pages updated:

  • System Design/Problem Designs/Design a URL shortener.md — added cache hit rate math, hot key problem + fixes, 3 new interviewer checklist items, Related link
  • synthesis/Interview Prep Hub.md — added L7 signals block (cost every component, hot key, cache math, failure-first, "we don't need X yet")

raw/ marked: ingested: true, wiki_pages_updated set index.md: +1 page (119 total), new SD entry, raw sources table populated

[2026-04-28] ingest | 3 articles processed — Redis, AI Concepts, Real SD Interviews

Redis Architecture Deep Dive (Nitesh Thakur)

Pages updated:

  • System Design/Caching & Redis.md — added "Redis Architecture Deep Dive" section: single-threaded model + I/O multiplexing, data structure internals (string encodings, list O(N) gotcha, sorted set dual-storage, hash ziplist 3x savings), persistence deep dive (RDB fork latency, AOF growth + BGREWRITEAOF, production guide), Lua scripts for atomicity, pipelining (100x), transactions no-rollback gotcha, memory management (eviction policies, fragmentation), monitoring (SLOWLOG, INFO), cluster hash tags

20 Most Important AI Concepts (Deep concept)

Pages created:

  • AI & ML/LLM Fundamentals.md — transformer stack (tokenization → embeddings → attention → transformer), LLM fundamentals (context window, temperature, hallucination), training optimization (fine-tuning, RLHF, LoRA, quantization), prompting (prompt engineering, CoT), AI systems (RAG, vector DB, agents, diffusion) Pages updated:
  • AI & ML/AI & ML Topics.md — checked off 7 items from LLM fundamentals checklist, added LLM Fundamentals to nav

Real SD Interviews at 10+ Companies (Freeze Francis)

Pages created:

  • System Design/Real Interview SD Questions.md — 10 real questions (pagination, WhatsApp, cross-DC replication, SIM store, saved-search notifications, push notifications, load balancer, bike rental, subscription payment), deep dives on pagination + chat + payment, patterns observed (push systems, LLD gap, domain-specific, seniority bar, tooling matters) Pages updated:
  • synthesis/Interview Prep Hub.md — added real interview patterns block

All 3 raw files: ingested: true index.md: +2 pages (121 total), all new pages + raw sources indexed

[2026-05-03] update | SQL knowledgebase expanded — 8 topic files added

Pages created:

  • SQL/Basics.md — SELECT, WHERE, ORDER BY, DISTINCT, NULL, COALESCE, CASE WHEN, data types, execution order
  • SQL/JOINs.md — INNER/LEFT/RIGHT/FULL OUTER/CROSS/self-join, anti-join patterns, NOT IN NULL gotcha
  • SQL/Aggregates.md — COUNT/SUM/AVG, GROUP BY, HAVING vs WHERE, conditional aggregates, ROLLUP
  • SQL/Subqueries & CTEs.md — scalar/correlated/EXISTS subqueries, CTEs, recursive CTEs with execution model
  • SQL/Window Functions.md — ROW_NUMBER/RANK/DENSE_RANK/NTILE, LAG/LEAD, running totals, frames, FIRST/LAST_VALUE
  • SQL/Indexes & Performance.md — B-tree/composite/partial/covering indexes, EXPLAIN ANALYZE, query optimization
  • SQL/Transactions.md — ACID verbal, isolation levels, SELECT FOR UPDATE, deadlocks, MVCC, optimistic locking
  • SQL/String & Date Functions.md — string ops, LIKE/ILIKE, date math, DATE_TRUNC, COALESCE/NULLIF, CAST, JSON

Pages updated:

  • SQL/SQL Topics.md — Quick Nav updated with links to all 8 new files
  • index.md — SQL section updated (2 → 10 pages), page_count 121 → 129

[2026-05-03] analysis | Senior analyst portfolio review (May 2026) — refreshed trackers from Monthly Data dump, combined corpus ₹40.32L (+₹8.56L since Apr 2). P1 +13.66%, P2 +5.79%. Updated Investment Tracker, Portfolio 2 Tracker, Combined Summary. Added global investment mandate (US ETFs ITA/SMH, SGBs, Indian REITs, tax-free PSU bonds) for 3-5yr horizon.

[2026-05-10] update | Window Functions — added ROWS vs RANGE INTERVAL example (date-gap gotcha for rolling-7-day sums, INTERVAL N DAY PRECEDING vs N PRECEDING rows).

[2026-05-10] ingest | xoraus/CrackingTheSQLInterview (115 Q&A SQL interview guide) — covered: DDL/DML/DCL/TCL classification, TRUNCATE vs DELETE vs DROP, AUTO_INCREMENT, all 6 constraints (NOT NULL/UNIQUE/PK/FK/CHECK/DEFAULT) + ON DELETE CASCADE/SET NULL/RESTRICT, Views (incl. materialized), Stored Procedures, Cursors (anti-pattern), Triggers (BEFORE/AFTER, NEW/OLD), SQL Injection defense (parameterized queries, identifier injection), GRANT/REVOKE, roles, least privilege. 4 new wiki pages created, SQL Topics nav + concept checklist updated, page_count 132 → 136.

[2026-05-10] progress | Last 2 weeks (W05 Apr 27–May 3 + W06 May 4–10) — SQL completed: DataLemur "Learn SQL" course done (SELECT/JOINs/aggregates/subqueries/window fns); LeetCode SQL 50 fully done (53 problems — full list in SQL Topics). All classic interview patterns covered cold (2nd highest salary, dept top-N, consecutive nums, dept highest salary, delete dup emails). W05 + W06 retrospectives + concept checklists updated. SQL track: interview-ready bar reached. Carry to W07: Trees DSA, Rate Limiter SD, Resume polish (deferred during SQL push).

[2026-05-11] carry | W05+W06 unfinished items rolled into W07 — Trees DSA (14 LC), Linked Lists DSA (9 LC), URL Shortener + Rate Limiter SD (carry W05–W06), Resume polish + send (carry W05). SQL track marked done — maintenance only.

[2026-05-16] progress | W1 gate closed — 15/15, PASS STRONG

LC 4 (Median of Two Sorted Arrays) solved in 30 min — senior bar. Binary search on smaller array, correct partition logic. Updated: Private/Project_2026/Weekly Tracker/Week 01 (May 11–17) — Validation Gate.md — #15 marked Done, Score: 15/15 PASS Updated: synthesis/Coach Hub.md — W1 status summary reflects 15/15 clean pass W2 direction: Linked List, 11 NeetCode problems, May 18–24.

[2026-05-16] update | Coach rearchitected — reads vault files directly, no stale memory

Problem solved: Memory files were stale (showed 0/15 problems solved; vault showed 14/15 with detailed notes).

New file created:

  • synthesis/Coach Hub.md — LLM-maintained coach state hub. Holds current_week_file pointer (updated each Sunday retro), W1 status summary, applications table, mocks done. Coach reads this first, then follows the pointer to the actual weekly tracker file.

coach.md rewritten (~/.claude/commands/coach.md):

  • Reads from vault: synthesis/Coach Hub.md → Private/Project_2026/Weekly Tracker/<current week>.md → synthesis/Job Switch Hub.md → Private/Project_2026/Projects Done.md
  • Keeps only feedback_dsa_solution_review.md in memory (Claude behavior instruction, not personal data)
  • Writes back only to synthesis/Coach Hub.md after retro/scorecard (never to Private/)

Hook fixed (.claude/settings.json):

  • Added vault-path guard — hook now only fires on files inside the vault directory
  • Previously over-triggered on ~/.claude/ files (coach.md, memory files)
  • Added /.claude/ and /memory/ to skip list

index.md: +1 page (Coach Hub), page_count 125→126

[2026-05-16] update | DSA Techniques overhaul — numbered files, index fixed, 3 notes upgraded

index.md:

  • Added 3 missing DSA Technique entries: Arrays & Hashing, Greedy, Math & Geometry
  • Fixed section header counts: DSA (15→27), Go (20→23), Python (7→10), AI & ML (3→4), FrontEnd (9→11)
  • page_count 122→125, last_updated 2026-05-16

DSA/DSA Techniques for Interviews/ — all 18 files renamed with numeric prefixes (01–18): 01. Arrays & Hashing → 18. Trapping Rain Water Visual (NeetCode curriculum order)

Cross-links fixed: all [[links]] inside technique files updated to numbered names

Technique notes upgraded:

  • 05. Binary Search.md — added rotated array pattern code (Pattern 4), find-min pattern (Pattern 5), bisect module examples, interview opener, while left<right vs <= explanation; removed placeholder Notes section
  • 11. Graphs.md — added grid DFS/BFS template (Pattern 6, LC 200), directed cycle detection with in-stack set (Pattern 7); removed placeholder Notes section
  • 08. Tries.md — added wildcard/dot search (Pattern 2, LC 211), Word Search II full code with trie pruning (Pattern 3, LC 212), expanded Senior Tricks

Verified excellent (no changes): Arrays & Hashing, Two Pointers, Sliding Window, Stacks, Linked Lists, Trees, Heap, Backtracking, Dynamic Programming, Greedy, Merge Intervals, Math & Geometry, Bit Manipulation, Prefix Sum

[2026-05-12] lint | Full vault audit + reorganization — 9 stale files removed, 6 files updated

Removed:

  • AWS/ML Associate Exam/ (7 files) → archived to Private/Archive/Deferred/AWS-ML-Cert/ (kill list: post-offer)
  • System Design/Backend 101/Concurrency/Concurrency.md — stub (20 lines), superseded by synthesis/Concurrency Deep Dive.md
  • System Design/Backend 101/Data Base/Basics.md — stub (19 lines), superseded by System Design/System Design Basics.md + SQL/

Updated:

  • index.md — removed dead links (PROJECT_2026_CONTEXT, Job Switch Plan 2026), updated synthesis page dates (→ 2026-05-12), fixed AWS section (ML exam removed), added Private Trackers with AskTGE + Coach file refs, page_count → 122
  • Private/Project_2026/Quick Links.md — moved killed resources (AWS cert, LangChain, Frontend SD) to new Deferred section; active list: NeetCode, Boot.dev, Gaurav Sen, Layrs.me
  • Private/Project_2026/Projects Done.md — populated with all 4 war stories: AskTGE perf audit, Chat History DynamoDB, TGE WebSocket, Splunk ML Thresholding
  • Private/Interview Questions for Project or behaviour/Past Experience Q&A For Interview.md — added YAML frontmatter + nav table
  • DSA/DSA Topics.md — added Greedy Algorithms (§10), Intervals (§11), Math & Geometry (§12) pattern tables; added NeetCode 150 progress tracker at bottom