StreamingDiskANN query-time parameters

You can also set two parameters to control the accuracy vs. query speed trade-off at query time. We suggest adjusting diskann.query_rescore to fine-tune accuracy.

Parameter name	Description	Default value
diskann.query_search_list_size	The number of additional candidates considered during the graph search.	100
diskann.query_rescore	The number of elements rescored (0 to disable rescoring)	50

You can set the value by using SET before executing a query. For example:

SET diskann.query_rescore = 400;

Note the SET command applies to the entire session (database connection) from the point of execution. You can use a transaction-local variant using LOCAL which will be reset after the end of the transaction:

BEGIN;
SET LOCAL diskann.query_search_list_size= 10;
SELECT * FROM document_embedding ORDER BY embedding <=> $1 LIMIT 10
COMMIT;