What does the ef_search parameter control in an HNSW vector index query?
- A Index build thread count
- B Number of candidates evaluated during search; higher = better recall but slower queries (correct answer)
- C Maximum distance threshold
- D Compression factor
Shortcut: ef_search=N controls the dynamic candidate list size during HNSW search. Higher values improve recall at the cost of query latency.
SET hnsw.ef_search=N controls the dynamic candidate list size during HNSW search. Higher values improve recall at the cost of query latency.