Plain vector RAG can't answer multi-hop or 'across everything' questions — the answer is spread across chunks that no single chunk contains. GraphRAG extracts a knowledge graph instead. Here's how it works, the honest cost, and how to start in Postgres without a graph database.
A modest app somehow grew Postgres, Redis, RabbitMQ, Elasticsearch and a vector DB — five things to back up, secure and pay for. Most of that is now one Postgres. Here's the queue, vector, search and pub/sub SQL, and the honest signals for when to graduate.