OpenSearch k-NN What Changed at 2.13+ OpenSearch 2.13 through 2.17 made the k-NN plugin competitive with purpose-built stores: - Lucene engine supports HNSW with filter-while-search (efficient filtering). - Faiss engine added IVF + PQ + binary + int8 quantization. - Neural search plugin: server-side embedding via external models (SageMaker, Bedrock). - Radial search: return all neighbors within a max distance. - Hybrid search plugin: BM25 + kNN with configurable score combiners. Engines: nmslib vs faiss vs lucene | Engine | Algorithms | Pros | Cons | |---|---|---|---| | lucene | HNSW | Best f…