From M AX S CORE to Block-Max Wand : The Story of How Lucene Significantly Improved Query Evaluation Performance

The latest major release of Lucene (version 8) in March 2019 incorporates block-max indexes and exploits the block-max variant of Wand for query evaluation, which are innovations that originated from academia. This paper shares the story of how this came to be, which provides an interesting case study at the intersection of reproducibility and academic research achieving impact in the “real world”. We offer additional thoughts on the often idiosyncratic processes by which academic research makes its way into deployed solutions.