This operation is performed for a single query
predicate.
Node name: XISCAN
Represents: Its
evaluation narrows down the qualifying return set of rows IDs and
XML node IDs by range scanning any associated index over XML data
before accessing the base table. The use of an index can improve the
performance of a query because the compiler determines whether and
how to use index information to complete the query. This typically
results in:
- The sorting of nodes by document and the elimination
of any duplicates.
- The fetching of each row of the table that
contains the qualifying
documents.
- An XSCAN operation on the XML document.