BitFunnel: How Bing Uses Bloom Filters for Search

Explore the innovative use of Bloom filters in Bing's search engine through this insightful lecture by Mike Hopcroft from Microsoft. Discover how the BitFunnel algorithm, which powers Bing's search capabilities, challenges conventional wisdom by employing Bloom filters for query processing. Learn about the journey of a small team that built a system capable of searching billions of documents, defying the long-held belief that signature files are inferior to inverted files for text indexing. Delve into the algorithmic innovations and changes in cloud computing that led to the development and deployment of BitFunnel, replacing an existing production system based on an inverted index. Understand the four fundamental limitations in bit-sliced block signatures that BitFunnel addresses, and how its implementation in a cluster environment offers cost-saving opportunities. Compare the efficiency gains of BitFunnel against classic bit-sliced signatures, Partitioned Elias-Fano Indexes, MG4J, and Lucene. Gain insights from Hopcroft's extensive background in electrical engineering, computational geometry, and computer vision, and his two-decade tenure at Microsoft working on various projects from Office to Bing.