The Three Real Options
There are 20+ vector databases. Three are what serious teams actually pick between in 2026: pgvector (a Postgres extension), Pinecone (managed, purpose-built), and Weaviate (open-source, self-hostable or managed).
pgvector
A Postgres extension that adds vector similarity to a regular relational database. The pitch: one database for everything.
Strengths: No new infrastructure. SQL queries can mix vector and metadata filters. Cheap. Transactional consistency.
Weaknesses: Performance ceilings at very large scale (tens of millions of vectors). Less specialized indexing than purpose-built tools.
Right when:You're already on Postgres and have under ~10M vectors. Most SMB and mid-market deployments.
Pinecone
Managed vector database, purpose-built. The pitch: don't think about infrastructure.
Strengths: Excellent performance at scale. Polished developer experience. Mature.
Weaknesses: Cost grows quickly with scale. Separate infrastructure to manage and authenticate. Vendor lock-in.
Right when:You're at very large scale or want to minimize ops burden, and the cost trade-off works.
Weaviate
Open-source vector database with managed and self-hosted options. The pitch: flexibility without lock-in.
Strengths: Powerful hybrid search built-in. Multi-modal support. Open source.
Weaknesses: More configuration than Pinecone. Self-hosting adds ops overhead.
Right when: You want managed simplicity with the option to self-host. Strong hybrid search needs.
- • Already on Postgres + under 10M vectors → pgvector.
- • Want zero infrastructure thought → Pinecone.
- • Want flexibility + strong hybrid search → Weaviate.
Decision Criteria
- Scale - how many vectors, how many queries/sec?
- Latency budget - p99 target?
- Hybrid search - need keyword + semantic?
- Existing stack - already on Postgres?
- Cost sensitivity - what's the budget at year 2?
- Ops capacity - can you run infrastructure?
Cost At Scale
At 1M vectors: pgvector ~$50/month on a small Postgres instance, Pinecone ~$70/month, Weaviate ~$50/month self-hosted or $200/month managed. At 50M vectors: pgvector $300–$500, Pinecone $1.5–$3k, Weaviate $300–$1.5k. Exact numbers vary; do your own math.
Migration Between Them
Wrap your vector layer behind a thin interface. Switching between any of the three is then a few days of work, not a rewrite. Avoid using provider-specific SQL extensions or query features.
For 80% of teams shipping RAG today, pgvector is the right answer. The other 20% know exactly why they need Pinecone or Weaviate - usually scale or a specific feature.
See RAG done right.
FAQ
What about Chroma, Milvus, Qdrant? All capable. We see less production adoption than the three above.
Cloud-vendor vector DBs? AWS, GCP, Azure all have offerings. Fine but more lock-in than self-hosted Weaviate.
Should we shard? Rarely below 100M vectors.