Vector DB / RAG Implementation Guide — From Naive RAG to Production
You know "what RAG is," but when you build one the answer comes out off — because it's still naive RAG: chop carelessly and do a plain vector search. As the implementation follow-up to article 030, this explains the 2026 practical RAG pipeline (smart chunking, embedding, vector DB, hybrid search, reranking) stage by stage: chunking strategies (recursive 512 default, semantic/structural/parent-child, Contextual Retrieval reportedly cutting retrieval failures up to 67%), choosing an embedding model (text-embedding-3-large, etc.), a comparison of six vector DBs (Chroma for prototyping, pgvector with Postgres, low-latency Qdrant, fully managed Pinecone, hybrid champion Weaviate, large-scale Milvus), hybrid search fusing BM25 + dense vectors with RRF, retrieve-then-rerank with a bi-encoder then cross-encoder (Cohere/Voyage/BGE/Jina), the LlamaIndex (retrieval) vs LangChain/LangGraph (control) split, why a 1M-token window doesn't replace RAG (lost in the middle, distraction), and productionization caveats like building an eval set first.