gracias por la respuesta, justo estaba revisando a profundidad las DOM Functions para manejo de documentos XML y lei el comentario del autor que mencionas
Cita: There are two widely-used methods for programming languages to read XML documents: event-based APIs and Document Object Model (DOM [11]) APIs. In the latter class of APIs, XML documents are read into memory in their entirety and can then be manipulated through a set of functions that provide access to an object oriented model of the document (the DOM) in memory. DOM APIs are generally considered to be more powerful; however, they suffer from one serious drawback: they are ill-suited to processing large XML documents, which would take too much memory to build the model of the document.
y bueno me surgio otra duda, cual es la definicion de un documento xml grande, o largo, de cuantas lineas, o peso, estamos hablando, haciendo un calculo aproximado veo que los archivos xml que me devuelven tendran un maximo aproximado de 400 lineas, sera esto mucho para una pc comun?, digamos de 128 de RAM