Efficient Merging and Filtering Algorithms for Approximate String Searches

We study the following problem: how to efficiently find in a collection of strings those similar to a given query string? Various similarity functions can be used, such as edit distance, Jaccard similarity, and cosine similarity. This problem is of great interests to a variety of applications that need a high real-time performance, such as data cleaning, query relaxation, and spellchecking. Several algorithms have been proposed based on the idea of merging inverted lists of grams generated from the strings. In this paper we make two contributions. First, we develop several algorithms that can greatly improve the performance of existing algorithms. Second, we study how to integrate existing filtering techniques with these algorithms, and show that they should be used together judiciously, since the way to do the integration can greatly affect the performance. We have conducted experiments on several real data sets to evaluate the proposed techniques.