How to choose a vector database for AI search in 2026? Most teams overthink this. pgvector on the Postgres you already operate handles 95% of B2B use cases. Reach for a dedicated vector DB only when filtering, scale, or hosted operations specifically demand it.
Decision rules in order
- 01Do you already operate Postgres? Use pgvector.
- 02Filtering on dozens of metadata fields? Qdrant.
- 03>100M vectors and you don't want to manage infra? Pinecone or Turbopuffer.
- 04Want everything as a managed bundle (schema + vectors + RAG endpoints)? Weaviate.
- 05On-prem only? pgvector or Qdrant (both self-host cleanly).
Common mistake: assuming vector DB = RAG
A vector DB is one component. Production RAG needs: chunking strategy, hybrid retrieval (BM25 + dense), reranker, citation enforcement, eval set. The vector DB is the easiest of those choices.
Cost reality check
| Option | Self-host | Managed monthly |
|---|---|---|
| pgvector | Free (your Postgres) | Supabase / Neon plans |
| Qdrant | Free OSS | Qdrant Cloud, mid-tier |
| Pinecone | No | Higher, predictable at scale |
| Turbopuffer | No | Pay-per-query, cheap at moderate scale |