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OpenSearch:DiskANN configuration

Last Updated:Oct 29, 2026

DiskANN is a disk-based approximate nearest neighbor search technology designed for very large datasets. It uses the Vamana graph algorithm to provide efficient vector indexing and retrieval with disk storage under limited memory.

Index build parameters

Parameter

Type

Description

proxima.diskann.builder.pq_dimension_scale

Int

The PQ quantization ratio. PQ dimension = vector dimension / pq_dimension_scale. Default: 8.

proxima.diskann.builder.max_degree

Int

The maximum number of outgoing edges of a node in the DiskANN graph. A larger value produces a more accurate graph but increases graph construction time.

proxima.diskann.builder.list_size

Int

The size of the candidate set for edge selection during DiskANN graph construction. A larger value produces a more accurate graph but increases graph construction time.

proxima.diskann.builder.thread_count

Int

The number of threads used to build the index.

Index search parameters

Parameter

Type

Description

proxima.diskann.searcher.list_size

Int

The size of the result candidate set. A larger value increases recall but also increases query time.

proxima.diskann.searcher.io_limit

Int

The disk I/O limit per query. At most io_limit disk read operations are performed. This value mainly affects the number of Vamana graph traversal operations. A larger value increases recall, the number of I/O operations, and query time.

proxima.diskann.searcher.beam_search_width

Int

The number of parallel I/O operations.