beyond lazy xml parsing：超越慵懒的解析.pdf

Beyond Lazy XML Parsing 1 Fernando Farfán, Vagelis Hristidis, Raju Rangaswami School puter and Information Sciences Florida International University {ffarfan,vagelis,raju}***@ Abstract. XML has e the standard format for data repres entation and exchange in domains ranging from Web to desktop app lications. However, wide adoption of XML is hindered by inefficient document -parsing methods. Recent work on lazy parsing is a major step towards allevi ating this problem. However, lazy parsers must still read the entire XML documen t in order to extract the overall document structure, due to the lack of internal nav igation pointers inside XML documents. Further, these parsers must load and par se the entire virtual document tree into memory during XML query processing. These overheads significantly degrade the performance of navigation operations. W e have developed a framework for efficient XML parsing based on the id ea of placing internal physical pointers within the document, which allows skipping large portions of the document during parsing. The internal pointers are generated in a way that optimizes parsing mon navigation patterns. A double-Lazy Parser (2LP) is then used to parse the document that exploits the i nternal pointers. To create the