Option 1
Postgres
Feature-rich; default for new projects; pgvector for AI.
Best for
Greenfield apps, anything that needs JSON-as-document, RAG / vector search, complex analytical queries, strict ACID + advanced indexing.
Pros
- Best-in-class feature set: JSON/JSONB indexing, full-text search, generated columns, partial indexes, materialized views
- Standards-compliant SQL — fewer 'this only works in MySQL' surprises
- pgvector for AI/RAG (embeddings + vector similarity search) is the standard
- Excellent extension ecosystem (PostGIS for geospatial, pg_cron for scheduling, Citus for distribution)
- Streaming replication + logical replication both first-class
- Available on every cloud (RDS, Supabase, Neon, Crunchy, Railway)
Cons
- Heavier than MySQL on small VMs (more memory baseline)
- Connection scaling needs a pooler (PgBouncer) past ~100 connections
- Vacuum + bloat behavior takes ops awareness on big workloads