Efficient evaluation of generalized tree-pattern queries with same-path constraints

Wu, X; Theodoratos, D; Souldatos, S; Dalamagas, T; Sellis, T

dc.contributor.author	Wu, X	en
dc.contributor.author	Theodoratos, D	en
dc.contributor.author	Souldatos, S	en
dc.contributor.author	Dalamagas, T	en
dc.contributor.author	Sellis, T	en
dc.date.accessioned	2014-03-01T02:46:07Z
dc.date.available	2014-03-01T02:46:07Z
dc.date.issued	2009	en
dc.identifier.issn	03029743	en
dc.identifier.uri	https://dspace.lib.ntua.gr/xmlui/handle/123456789/32563
dc.subject	Asymptotic Optimality	en
dc.subject	Directed Acyclic Graph	en
dc.subject	Evaluation Model	en
dc.subject	Experimental Evaluation	en
dc.subject	Polynomial Time	en
dc.subject	Query Language	en
dc.subject	Scientific Application	en
dc.subject	Theoretical Analysis	en
dc.subject.other	Asymptotically optimal	en
dc.subject.other	Directed acyclic graphs	en
dc.subject.other	Evaluation algorithm	en
dc.subject.other	Evaluation models	en
dc.subject.other	Experimental evaluation	en
dc.subject.other	Flexible querying	en
dc.subject.other	Inverted list	en
dc.subject.other	Main-memory	en
dc.subject.other	Partial trees	en
dc.subject.other	Path constraint	en
dc.subject.other	Pattern query	en
dc.subject.other	Polynomial-time	en
dc.subject.other	Scientific applications	en
dc.subject.other	Structural fragments	en
dc.subject.other	Structural pattern	en
dc.subject.other	XML data	en
dc.subject.other	Algorithms	en
dc.subject.other	Asymptotic analysis	en
dc.subject.other	Linguistics	en
dc.subject.other	Management information systems	en
dc.subject.other	Markup languages	en
dc.subject.other	Polynomial approximation	en
dc.subject.other	XML	en
dc.subject.other	Query languages	en
dc.title	Efficient evaluation of generalized tree-pattern queries with same-path constraints	en
heal.type	conferenceItem	en
heal.identifier.primary	10.1007/978-3-642-02279-1_27	en
heal.identifier.secondary	http://dx.doi.org/10.1007/978-3-642-02279-1_27	en
heal.publicationDate	2009	en
heal.abstract	Querying XML data is based on the specification of structural patterns which in practice are formulated using XPath. Usually, these structural patterns are in the form of trees (Tree-Pattern Queries - TPQs). Requirements for flexible querying of XML data including XML data from scientific applications have motivated recently the introduction of query languages that are more general and flexible than TPQs. These query languages correspond to a fragment of XPath larger than TPQs for which efficient non-main-memory evaluation algorithms are not known. In this paper, we consider a query language, called Partial Tree-Pattern Query (PTPQ) language, which generalizes and strictly contains TPQs. PTPQs represent a broad fragment of XPath which is very useful in practice. We show how PTPQs can be represented as directed acyclic graphs augmented with same-path constraints. We develop an original polynomial time holistic algorithm for PTPQs under the inverted list evaluation model. To the best of our knowledge, this is the first algorithm to support the evaluation of such a broad structural fragment of XPath. We provide a theoretical analysis of our algorithm and identify cases where it is asymptotically optimal. In order to assess its performance, we design two other techniques that evaluate PTPQs by exploiting the state-of-the-art existing algorithms for smaller classes of queries. An extensive experimental evaluation shows that our holistic algorithm outperforms the other ones. © 2009 Springer Berlin Heidelberg.	en
heal.journalName	Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)	en
dc.identifier.doi	10.1007/978-3-642-02279-1_27	en
dc.identifier.volume	5566 LNCS	en
dc.identifier.spage	361	en
dc.identifier.epage	379	en