An HNSW index build on 5 million vectors is extremely slow. Which server parameter most improves build time?

1. A work_mem
2. ✓ B maintenance_work_mem (correct answer)
3. C max_connections
4. D effective_cache_size

Shortcut: Index construction uses maintenance_work_mem. Raising it (and max_parallel_maintenance_workers) lets more of the graph be built in memory, substantially reducing build time.