Hybrid Search in OpenSearch: Combining BM25 and Vector Search with RRF
· 5 min read
BM25 is precise on exact terms but blind to meaning. Vector search is rich in semantics but can return spurious matches when query and document happen to point in similar directions by coincidence. Hybrid search combines both signals. This post shows how to configure a Reciprocal Rank Fusion (RRF) pipeline in OpenSearch 2.19.1 and documents the difference in results across three approaches, using real scores from a FoundryDB-managed cluster.
All commands use YOUR_OPENSEARCH_HOST and YOUR_PASSWORD as placeholders.