DARTH: Declarative Recall Through Early Termination for Approximate Nearest Neighbor Search

TL;DR

DARTH introduces a novel method for approximate nearest neighbor search that guarantees user-defined recall levels through adaptive early termination, significantly improving search speed across various algorithms.

Contribution

DARTH provides a declarative recall mechanism with an adaptive early termination strategy, simplifying parameter tuning and ensuring consistent recall for all queries.

Findings

Achieves up to 14.6x speedup for HNSW

Achieves up to 41.8x speedup for IVF

Effectively meets user-defined recall targets

Abstract

Approximate Nearest Neighbor Search (ANNS) presents an inherent tradeoff between performance and recall (i.e., result quality). Each ANNS algorithm provides its own algorithm-dependent parameters to allow applications to influence the recall/performance tradeoff of their searches. This situation is doubly problematic. First, the application developers have to experiment with these algorithm-dependent parameters to fine-tune the parameters that produce the desired recall for each use case. This process usually takes a lot of effort. Even worse, the chosen parameters may produce good recall for some queries, but bad recall for hard queries. To solve these problems, we present DARTH, a method that uses target declarative recall. DARTH uses a novel method for providing target declarative recall on top of an ANNS index by employing an adaptive early termination strategy integrated into the search algorithm. Through a wide range of experiments, we demonstrate that DARTH effectively meets user-defined recall targets while achieving significant speedups, up to 14.6x (average: 6.8x; median: 5.7x) faster than the search without early termination for HNSW and up to 41.8x (average: 13.6x; median: 8.1x) for IVF. This paper appeared in ACM SIGMOD 2026.