Lesson 4 of 5 · 16 min read

Vector Databases: When to Actually Use One

For under 100K chunks, you don't need Pinecone. Here's what to use instead.

Vector databases (Pinecone, Weaviate, Qdrant, Chroma) are great — and overused.

Under 10K chunks? An in-memory array + cosine similarity. No database needed.
10K – 1M chunks? pgvector on Postgres. Same DB as the rest of your app.
1M+ chunks or multi-tenant SaaS? Dedicated vector DB (Qdrant self-hosted is a strong default).