The XML parser in the Integration Server supports streaming-parse-on-demand, therefore, there the complete XML file never has to be in memory to be parsed.
That being said, it depends what operations you are performing on the XML file. There is a document or section of a document on Large Document Handling in most of the Integration Platform Components (Trading Networks, EDI, etc).
For instance, XQL queries require the complete document to be in memory. pub.web:documentToRecord creates an IData representation of the complete document, but pub.web:nodeIterator supports a “moving window” of parsed XML, which can support arbitrarily large documents.
#webMethods#webMethods-General#Integration-Server-and-ESB