Abstract

Dealing effectively with large volumes of semistructured data requires efficient retrieval. Finding all occurrences of a given word in a large static text is a well-studied problem. Most solutions, however, are not well-suited for phrase-searching. In this paper, we investigate a new algorithm to find all occurrences of a given phrase in a large, static text, based on the data structure known as a suffix array. Using this algorithm, phrases of bounded length can be found with expected search time of one disk access to the text and one disk access to an index. To achieve this performance for phrases of up to five words in length requires an index having total size of approximately 120% of the size of the text. The algorithm guarantees a worst case search performance of 2 disk accesses to the text per phrase search. The method augments a suffix array with a parallel signature array, so that every indexed phrase has an associated signature. To search for a phrase, we search a block of the...

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