Caching Scores for Faster Query Processing with Dynamic Pruning in Search Engines

We propose to use a score cache, which stores the score of the k.th result of a query, to accelerate top-k query processing with dynamic pruning methods (i.e., WAND and BMW). We introduce heuristics that, for a new query, generate its subsets and probe the score cache to obtain a lower-bound on its score threshold. Our experiments show up to 8.6% savings in mean processing time for the queries that are not seen before, i.e., cannot benefit from a result cache.