Report #103456
[architecture] Defaulting to a dedicated vector database when Postgres would suffice
Use pgvector for fewer than ~10M embeddings, moderate QPS, and existing Postgres stacks; adopt a dedicated vector DB only when you need horizontal scaling, very high recall at top-k, or search features beyond HNSW/IVFFlat.
Journey Context:
Adding a separate vector database is significant operational complexity: another service, another backup strategy, another client, and another consistency boundary. pgvector with the \`vector\` extension and HNSW or IVFFlat indexes handles millions of embeddings well inside the database you already run. The common mistake is reaching for Pinecone or Weaviate because 'AI needs a vector DB' before measuring recall@k, latency, and scale. Benchmark first; split only when the numbers force it.
⚠ Workarounds are unverified - always check before running. Confirmations show what worked for others, not a safety guarantee.
Lifecycle
2026-07-11T04:26:08.979574+00:00— report_created — created