Title
Fast in-memory XPath search using compressed indexes.
Abstract
A large fraction of an XML document typically consists of text data. The XPath query language allows text search via the equal, contains, and starts-with predicates. Such predicates can be efficiently implemented using a compresse d self-index of the document's text nodes. Most queries, however, contain some parts querying the text of the document, plus some parts querying the tree structure. It is therefore a challen ge to choose an appropriate evaluation order for a given query, which optimally leverages the execution speeds of the text and tree indexes. Here the SXSI system is introduced. It stores the tree structure of an XML document using a bit array of opening and closing brackets plus a sequence of labels, and stores the text nodes of the document using a global compressed self-index. On top of these indexes sits an XPath query engine that is based on tree automata. The engine uses fast counting queries of the text index in order to dynamically determine whether to evaluate top-down or bottom-up with respect to the tree structure. The resulting system has several advantages over existing systems: (1) on pure tree queries (without text search) such as the XPathMark queries, the SXSI system performs on par or better than the fastest known systems MonetDB and Qizx, (2) on queries that use text search, SXSI outperforms the existing systems by 1-3 orders of magnitude (depending on the size of the result set), and (3) with respect to memory consumption, SXSI outperforms all other systems for counting-only queries.
Year
DOI
Venue
2010
10.1109/ICDE.2010.5447858
Softw., Pract. Exper.
Keywords
DocType
Volume
tree data structures,query languages,text search,text analysis,xml document,indexation,database languages,top down,indexes,data structures,query language,computer science,bottom up,search engines,memory management,xml,tree structure,pediatrics,engines,system performance,automata
Conference
45
Issue
ISSN
ISBN
3
0038-0644
978-1-4244-5444-0
Citations 
PageRank 
References 
7
0.43
42
Authors
8
Name
Order
Citations
PageRank
Diego Arroyuelo120812.97
Francisco Claude255426.10
Sebastian Maneth397561.51
Veli Mäkinen4158385.29
Gonzalo Navarro564735.74
Kim Nguyen6736.80
Jouni Sirén722214.85
Niko Välimäki827614.53