What is the pgvector index type that offers better recall at query time compared to IVFFlat, at the cost of longer build time?

1. A B-tree
2. B GIN
3. C IVFFlat
4. ✓ D HNSW (correct answer)

Shortcut: HNSW (Hierarchical Navigable Small World) provides better recall and faster query performance than IVFFlat at the cost of more memory and longer index build time.