AS-Index: A Structure For String Search Using n-grams and Algebraic Signatures
Constantin, Camelia; du Mouza, Cedric; Litwin, Witold; Rigaux, Philippe; Schwarz, Thomas (2016), AS-Index: A Structure For String Search Using n-grams and Algebraic Signatures, Journal of Computer Science and Technology, 31, 1, p. 147–166. 10.1007/s11390-016-1618-6
TypeArticle accepté pour publication ou publié
External document linkhttps://hal.archives-ouvertes.fr/hal-01126550
Journal nameJournal of Computer Science and Technology
MetadataShow full item record
du Mouza, Cedric
Laboratoire d'analyse et modélisation de systèmes pour l'aide à la décision [LAMSADE]
Abstract (EN)We present the AS-Index, a new index structure for exact string search in disk resident databases. AS-Index relies on a classical inverted file structure, whose main innovation is a probabilistic search based on the properties of algebraic signatures used for both n-grams hashing and pattern search. Specifically, the properties of our signatures allow to carry out a search by inspecting only two of the posting lists. The algorithm thus enjoys the unique feature of requiring a constant number of disk accesses, independently from both the pattern size and the database size. We conduct extensive experiments on large datasets to evaluate our index behavior. They confirm that it steadily provides a search performance proportional to the two disk accesses necessary to obtain the posting lists. This makes our structure a choice of interest for the class of applications that require very fast lookups in large textual databases. We describe the index structure, our use of algebraic signatures, and the search algorithm. We discuss the operational trade-offs based on the parameters that affect the behavior of our structure, and present the theoretical and experimental performance analysis. We next compare the AS-Index with the state-of-the-art alternatives and show that 1) its construction time matches that of its competitors, due to the similarity of structures, 2) as for search time, it constantly outperforms the standard approach, thanks to the economical access to data complemented by signature calculations, which is at the core of our search method.
Subjects / KeywordsFull text indexing; Large scale indexing; Algebraic signatures; Signatures algébriques; Indexation de grande échelle; L'indexation de texte intégral
Showing items related by title and author.
Cumulative Algebraic Signatures for Fast String Search, Protection Against Incidental Viewing and Corruption of Data in an SDDS Litwin, Witold; Mokadem, Riad; Schwarz, Thomas (2007) Communication / Conférence