xmlWriter are very fast, given
that they are little more than wrappers for direct reading/writing
that process extra information, or add extra information,
respectively. The amount of time to open a handle XML data is
constant, as it is not affected by the size of the XML data.
xmlTree, the entire XML document needs to be read
and parsed before any operations can be performed on it, so it is
affected by the size of the XML data. The
xmlTree API is
very fast for an XML parser, but there will still be a noticeable
delay when parsing 900MB of XML data, for example.