16. The computer program product of claim 15 wherein an index is matched to said pre-filter.
15. A computer program product for querying an XML document, said computer program product comprising: a computer readable storage medium, wherein said computer readable storage medium is selected from a group consisting of an electronic device, a magnetic device, an optical device, an electromagnetic device, an infrared device, a semiconductor device, a semiconductor memory, a solid state memory, a magnetic tape, a removable computer diskette, a random access memory (RAM), a read-only memory (ROM), a rigid magnetic disk, an optical disk, a compact disk—read-only memory (CR-ROM), a compact disk—read/write (CD-R/W), and a DVD, said computer readable storage medium having computer readable program code embodied therewith, said computer readable program code comprising: computer readable program code configured to: transforming, via an execution compiler included in an XML compilation processor, an XML query into an XML query plan, said transforming into said XML query plan comprising: identifying an XPath within said XML query using a query rewrite processor included in said XML compilation processor; and transforming, via query transformation on said XML query, said XPath into a pre-filter of said XML query using said query rewrite processor, wherein said query rewrite processor is adapted to perform said query transformation by transforming the expression: $i[e 1 ][e 2 ] into the expression $i[e 1 ][e 2 ]/e 2 , wherein e 1 is a filter and e 2 is a deterministic XQuery expression, and wherein subsequent to said transforming of the expression, applying said XML query to a sequence of XML items selected from a group consisting of: a sequence of XML items extracted from one or more extensible markup language (XML) documents, a sequence of XML items supplied by an Internet service, a sequence of HTML items extracted from one or more hypertext markup language (HTML) documents, and a sequence of HTML items supplied by an Internet service.