Prefiltering techniques for efficient XML document processing

Abstract

Document Object Model (DOM) and Simple API for XML (SAX) are the two major programming models for XML document processing. Each, however, has its own efficiency limitation. DOM assumes an in-core representation of XML documents which can be problematic for large documents. SAX needs to scan over the document in a linear manner in order to locate the interesting fragments. Previously, we have used tree-to-table mapping and indexing techniques to help answer structural queries to large, or large collections of, XML documents. In this paper, we generalize the previous techniques into a prefiltering framework where repeated access to large XML documents can be efficiently carried out within the existing DOM and SAX models. The prefiltering framework essentially uses a tiny search engine to locate useful fragments in the target XML documents by approximately executing the user's queries. Those fragments are gathered into a candidate-set XML document, and is returned to the user's DOM-or SAX-based applications for further processing. This results in a practical and efficient model of XML processing, especially when the XML documents are large and infrequently updated, but are frequently being queried.

2LP: A double-lazy XML parser

“…Huang et al [38,39] present a pre-filtering framework to improve the efficiency of XPath processing over large XML documents with the existing DOM and SAX models. Their framework utilizes an inverted index and a tiny search engine that locates the useful fragments that may be candidates to satisfy the input XPath query, and only these fragments are submitted to the XML parser.…”

Document engineering approaches toward scalable and structured multimedia, web and printable documents

“…XML itself has been investigated in several fronts, for instance in terms of extensions that bring notions from functional programming to web authors [34], of prefiltering techniques for efficient XML document processing [17], XML query performance [29,30] and version control [27]. Extended versions of two of these works are presented in this special issue.…”

Querying and browsing XML and relational data sources

“…Each unit is identified by a unique integer, and each context in the unit is represented as a value under the attribute Context. A set of mutually recursive rewrite rules can been defined for compiling each UDA query Q to an answer preserving relational query, α(Q), in the sense that u ∈ Q iff there exists an integer i such that u = ∪ c∈π Context (σ Id=i (α(Q))) c. An alternative implementation approach under investigation is to adapt the indexing techniques developed in [9] for prefiltering XML documents.…”

“…The work is a continuation of our investigation into data integration methods for heterogeneous data models [13] and efficient query processing techniques for XML data [9]. The next section introduces the basics of our data model -the universal data model, including an algebraic language for data manipulation.…”