receiving a data query for a set of hierarchical markup documents;

extracting at least one query path expression from the data query;

processing the query path against at least one shared hierarchical markup document in a plurality of shared hierarchical markup documents, wherein the plurality of shared hierarchical documents is associated with the set of hierarchical markup documents;

generating, in response to the shared hierarchical markup document completely matching the query path expression, a query result for the data query based on the processing of the query path expression against at least one of the shared hierarchical markup document and the difference hierarchical markup document.