HNSW defaults can look fast while missing useful results. Production tuning needs recall@k, p99, index build time, memory, and filtered result count together.
Database Topic Archive
pgvector and RAG Articles
HNSW, IVFFlat, recall, embedding search, and production RAG performance notes.
Vector search looks easy until tenant filters, permissions, freshness, and deleted content arrive. The hard part is not nearest neighbors; it is filtered recall under production rules.
Multi-tenant vector search is a correctness and isolation problem. Namespaces, filters, and partitions each fail differently under tenant skew and ACL rules.
Hybrid search helps when exact terms and semantic meaning both matter. It fails when teams blend rankings without query intent, calibration, or evaluation.
The hard vector database decision is not pgvector versus Pinecone on a checklist. It is whether your filters, recall target, update rate, and incident budget still fit inside Postgres.