Users can now benefit from more efficient query filtering with OpenSearch’s k-NN FAISS engine by using OpenSearch 2.9 on the Amazon OpenSearch Service. Previously exclusive to OpenSearch’s Lucene k-NN engine, OpenSearch’s efficient vector query filters capability intelligently evaluates optimal filtering strategies—like pre-filtering with approximate nearest neighbor (ANN) or filtering with exact k-nearest neighbor (k-NN)—to determine the best strategy to deliver accurate and low latency vector search queries. In earlier OpenSearch versions, vector queries on the FAISS engine used post-filtering techniques, which enabled filtered queries at scale, but it potentially returns less than the requested “k” number of results.
Source:: Amazon AWS