Redefining Hybrid Search Possibilities with Vespa - part one

The blog post discusses the capabilities of Vespa in redefining hybrid search by effectively integrating both sparse and dense representational approaches for efficient information retrieval and ranking. Vespa's ability to handle large-scale document collections is highlighted through its support for phased ranking, allowing retrieval and ranking to be expressed in the same query using operators like nearestNeighbor and wand. The post contrasts Vespa's approach with traditional systems, emphasizing the advantages of using Vespa's query language for top-k scoring without scoring all documents. It explores the use of sparse representations through models like BM25 and SPLADE, leveraging dynamic pruning algorithms such as WAND to optimize search efficiency. Additionally, dense representations use vector similarity functions, often requiring transformations with language models, and Vespa supports hybrid retrieval by combining sparse and dense methods within a single query. The post concludes by indicating that the combination of sparse and dense ranking signals will be further discussed in a subsequent post.