pgvector
Postgres extension that adds the `vector` type and distance operators (`<->`, `<=>`). Lets you do RAG without deploying a dedicated DB, the same Postgres serving your app also serves your embeddings. Active on Supabase by default.
Strengths
- Single DB for your app and embeddings
- Native SQL joins between app tables and embedding table
- Enabled by default on Supabase, `CREATE EXTENSION vector;` and go
Limitations
- HNSW index slower than a real dedicated vector DB beyond a few million vectors
- Requires minimal SQL to query (vs ChromaDB which is full-Python)
Best for
- Apps already running Postgres or Supabase
- RAG with SQL joins (e.g. filter by user_id then vector search)