Index Parameter Range

Searching with most indexes that Milvus supported requires specifying construction and search parameters. Listed below are the type and ranges of these parameters.

Index	Type	Const. Param & Range	Search Param & Range	Note
Flat	entity.Flat	N/A	N/A	No parameter is required for search with Flat.
BinFlat	entity.BinFlat	nlist∈[1, 65536]	nprobe∈[1, nlist]
IvfFlat	entity.IvfFlat	nlist∈[1, 65536]	nprobe∈[1, nlist]
BinIvfFlat	entity.BinIvfFlat	nlist∈[1, 65536]	nprobe∈[1, nlist]	BinIvfFlat will be supported in upcoming version of Milvus.
IvfSQ8	entity.IvfSQ8	nlist∈[1, 65536]	nprobe∈[1, nlist]
IvfSQ8H	entity.IvfSQ8H	nlist∈[1, 65536]	nprobe∈[1, nlist]
IvfPQ	entity.IvfPQ	nlist∈[1, 65536] m dim===0 (mod self) nbits∈[1, 16]	nprobe∈[1, nlist]
RNSG	entity.NSG	out_degree∈[5, 300] candidate_pool_size∈[50, 1000] search_length∈[10, 300] knng∈[5, 300]	search_length∈[10, 300]
HNSW	entity.HNSW	M∈[4, 64] efConstruction∈[8, 512]	ef∈[topK, 32768]
RHNSWFlat	entity.RHNSWFlat	M∈[4, 64] efConstruction∈[8, 512]	ef∈[topK, 32768]
RHNSW_PQ	entity.RHNSW_PQ	M∈[4, 64] efConstruction∈[8, 512] PQM dim===0 (mod self)	ef∈[topK, 32768]
RHNSW_SQ	entity.RHNSWSQ	M∈[4, 64] efConstruction∈[8, 512]	ef∈[topK, 32768]
IvfHNSW	entity.IvfHNSW	nlist∈[1, 65536] M∈[4, 64] efConstruction∈[8, 512]	nprobe∈[1, nlist] ef∈[topK, 32768]
ANNOY	entity.ANNOY	n_trees∈[1, 1024]	search_k∈-1 or [topk, n * n_trees]
NGTPANNG	entity.NGTPANNG	edge_size∈[1, 200] forcedly_pruned_edge_size∈[selectively_pruned_edge_size + 1, 200] selectively_pruned_edge_size∈[1, forcedly_pruned_edge_size -1 ]	max_search_edges∈[-1, 200] epsilon∈[-1.0, 1.0]	Search parameter epsilon type is float64.
NGTONNG	entity.NGTONNG	edge_size∈[1, 200] outgoing_edge_size∈[1, 200] incoming_edge_size∈[1, 200]	max_search_edges∈[-1, 200] epsilon∈[-1.0, 1.0]	Search parameter epsilon type is float64.