Day 4: GraphRAG Explained: Combining Knowledge Graphs with Vector Search
Production RAG Masterclass · Day 4 of 7 Some questions are not “find the nearest paragraph.” They are “walk a path across three documents and explain the join.” Flat vector search was never designed for that. Figure 1. Vectors find seeds. Graphs find relationships. Thesis Cosine similarity cannot infer multi-hop entity relationships across separate documents. Pair vectors with an entity–relation graph. Where flat vector RAG breaks Ask: “Which vendors touch the same data pipeline as Team Atlas, and who owns the SLA?” The facts live in an org chart, a vendor contract, and a runbook. No single chunk holds the full path. Similarity returns locally relevant paragraphs — not the chain. Build the graph at ingest Extract triples while you chunk: (Entity) -[RELATION]-> (Entity) (Team Atlas)-[OWNS]->(Billing Pipeline) (Billing Pipeline)-[DEPENDS_ON]->(Vendor Stripe) (Vendor Stripe)-[HAS_SLA]->(99.95%) Store nodes and edges in Neo4j (or similar). Keep chunk t...