A Fast Tree Pattern Matching Algorithm for XML Query

Finding all distinct matchings of the query tree pattern is the core operation of XML query evaluation. The existing methods for tree pattern matching are decomposition-matching-merging processes, which may produce large useless intermediate result or require repeated matching of some sub-patterns. We propose a fast tree pattern matching algorithm called TreeMatch to directly £nd all distinct matchings of a query tree pattern. The only requirement for the data source is that the matching elements of the non-leaf pattern nodes do not contain sub-elements with the same tag. The TreeMatch does not produce any intermediate results and the £nal results are compactly encoded in stacks, from which the explicit representation can be produced ef£ciently.