An apparatus is provided that includes a processor and memory storing executable instructions that in response to execution by the processor cause the apparatus to at least perform a number of operations. The apparatus is caused to receive a rowset of data from a data source, where the rowset includes one or more rows of values from the data source. The apparatus is caused to convert the rowset to markup data, and organize the markup data in preparation for its transformation to an output according to a markup transformation language. The markup data includes, for each row of the rowset, a row markup element; and the organized markup data includes an organization of the row elements into a plurality of logical groups. Even further, the organized markup data may be split into a plurality of smaller markup data sets, which may facilitate transformation of the markup data.