Mule のドキュメントから直接:
Efficient Transformations with DelayedResult
Mule contains a special XML output format called DelayedResult. This format allows very efficient XML transformations by delaying any XML serialization until an OutputStream is available.
For example, here is an XSLT transformer set up to use DelayedResult:
<mxml:xslt-transformer name="transform-in"
xsl-file="xslt/transform.xslt"
returnClass="org.mule.module.xml.transformer.DelayedResult"/>
If the result of this transformation were being sent to an HTTP client, the HTTP client would ask Mule for an OutputHandler and pass in the OutputStream to it. Only then would Mule perform the transformation, writing the output directly to the OutputStream.
If DelayedResult were not used, the XML result would first be written to an in-memory buffer before being written to the OutputStream. This will cause your XML processing to be slower.
したがって、XQuery トランスフォーマーの代わりに XSLT トランスフォーマーを使用する方が理にかなっています。