Optimizing XML Querying Using Type-Based Document Projection

XML data projection (or pruning) is a natural optimization for main memory query engines: given a query Q over a document D, the sub-trees of D that are not necessary to evaluate Q are pruned, thus producing a smaller document D; the query Q is then executed on D0, hence avoiding to allocate and process nodes that will never be reached by Q. In this paper, the authors propose a new approach, based on types, that greatly improves current solutions. Besides providing comparable or greater precision and far lesser pruning overhead, their solution - unlike current approaches - takes into account backward axes, predicates, and can be applied to multiple queries rather than just to single ones.

Provided by: Association for Computing Machinery Topic: Data Management Date Added: Mar 2013 Format: PDF

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