Week 05 — RAG fundamentals, caching, hexagonal¶

At a glance

Phase 2: RAG + Evals · Starts: Mon 26 Oct 2026 · Planned: 16h 45m

Build: Capstone: RAG v0 — ingest runbooks/postmortems into pgvector, naive dense retrieval behind a Retriever port

By day¶

System Design · 45 min · Caching strategies: cache-aside, write-through, write-behind, TTL + stampede protection (request coalescing, probabilistic early expiry) → Caching strategies w05-sd-1
DSA · 25 min · Generate Parentheses (stack + backtracking warm-up) → Stack & monotonic stack · resource w05-dsa-1
Python · 20 min · Rep: pytest fixtures with scopes + factories; parametrize retrieval tests → Testing: pytest, fixtures, Hypothesis, testcontainers w05-py-1
Communication · 30 min · Grammar: Sentence structure and parallelism → Week 05 drills · day 1 w05-comm-1

Agentic AI · 60 min · RAG fundamentals: chunking strategies (fixed, recursive, semantic, structure-aware), embedding model choice, top-k — write a comparison table for runbooks/postmortems → RAG fundamentals: chunking, embeddings, retrieval · resource w05-ai-1
DSA · 30 min · Binary Search + Search a 2D Matrix → Binary search (incl. on answer) · resource w05-dsa-2
Communication · 30 min · Vocabulary: Analytical words: consequently, whereas, mitigate, hinge on → Week 05 drills · day 2 w05-comm-2

DSA · 25 min · Koko Eating Bananas (binary search on answer) → Binary search (incl. on answer) · resource w05-dsa-3
Architecture · 45 min · Cosmic Python ch1-3 / hexagonal architecture: domain model, repository, ports & adapters — sketch capstone layers → Hexagonal / clean architecture, ports & adapters · resource w05-arch-1
Python · 20 min · Rep: Repository pattern for chunks (abstract base vs Protocol), in-memory fake for tests → Architecture patterns in Python (repository, UoW, message bus) · resource w05-py-2
Communication · 30 min · Speaking drill: PREP and pyramid structure for answers → Week 05 drills · day 3 w05-comm-3

Agentic AI · 60 min · Vector databases: pgvector HNSW vs IVFFlat parameters (m, ef_construction, ef_search, lists) — build an index on 50k chunks and measure recall@10 vs latency → Vector databases: pgvector, Qdrant & friends · resource w05-ai-2
Java/Spring AI · 30 min · Spring AI VectorStore with PgVectorStore: configure dimensions, index type, metadata filters → RAG with Spring AI & pgvector · resource w05-java-1
Communication · 30 min · Idioms & phrasal verbs: Strategy metaphors: low-hanging fruit, moving parts → Week 05 drills · day 4 w05-comm-4

System Design · 45 min · Storage engines: B-tree vs LSM-tree, write/read amplification (DDIA 2e storage chapter) → Databases: SQL vs NoSQL, storage engines · resource w05-sd-2
DSA · 25 min · Find Minimum in Rotated Sorted Array → Binary search (incl. on answer) · resource w05-dsa-4
Python · 20 min · Rep: iter/len/getitem on a ChunkCollection; sequence protocol vs subclassing list → Python data model & dunder protocols · resource w05-py-3
Communication · 30 min · Writing: Writing a design-doc summary → Week 05 drills · day 5 w05-comm-5

Agentic AI · 120 min · Capstone build: ingestion pipeline (Markdown/PDF → chunks → embeddings → pgvector via docker-compose) + Retriever port with dense adapter; answer with citations → RAG fundamentals: chunking, embeddings, retrieval w05-ai-3
DSA · 30 min · Search in Rotated Sorted Array + Time Based Key-Value Store → Binary search (incl. on answer) · resource w05-dsa-5
Java/Spring AI · 30 min · Spring AI ETL: DocumentReader → TokenTextSplitter → VectorStore for the same runbook corpus → RAG with Spring AI & pgvector w05-java-2
Communication · 30 min · Record & shadow: PREP and pyramid structure for answers → Week 05 drills · day 6 w05-comm-6

System Design · 45 min · Written design: apply your AI system design framework to 'design an internal support chatbot' — requirements, data, model choice, eval plan, risks → AI system design interview framework · resource w05-sd-3
Architecture · 30 min · Write ADR 005 for capstone: hexagonal layout with retrieval, LLM and ticketing as ports → Hexagonal / clean architecture, ports & adapters · resource w05-arch-2
Staff+ · 30 min · Outline the capstone design doc (context, goals/non-goals, architecture, alternatives, risks, rollout) → Design docs & RFCs that get approved w05-staff-1
Communication · 30 min · Soft skills + weekly review: Facilitating a meeting → Week 05 drills · day 7 w05-comm-7
Review · 60 min · Explain-it-back: caching stampede mitigations + LSM vs B-tree in 3 min each; 20 flashcards on RAG vocabulary → Caching strategies w05-rev-1