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OpenSearch:DiskANN configuration

Last Updated:Jul 10, 2025

DiskANN is a disk-based approximate nearest neighbor search technology specifically designed for processing ultra-large-scale datasets. It uses the Vamana graph algorithm to store data on disk while maintaining efficient vector indexing and retrieval under limited memory conditions.

DiskANN index build parameters

Parameter

Type

Description

proxima.diskann.builder.pq_dimension_scale

Int

The scale for PQ quantization. PQ dimension = vector dimension/pq_dimension_scale. Default value: 8.

proxima.diskann.builder.max_degree

Int

The maximum number of output nodes for a node in the DiskANN graph. A larger value results in a more accurate graph but increases the 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 results in a more accurate graph but increases the graph construction time.

proxima.diskann.builder.thread_count

Int

The number of threads for index building.

DiskANN index search parameters

Parameter

Type

Description

proxima.diskann.searcher.list_size

Int

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

proxima.diskann.searcher.io_limit

Int

The disk I/O limit for a single query. A maximum of io_limit disk read operations will be performed. This mainly affects the number of Vamana graph walks. A larger value results in higher recall and more I/O operations, which increases query time.

proxima.diskann.searcher.beam_search_width

Int

The number of parallel I/O operations.