[thelist] document function in xslt

[Stevenson Ngila]

does the use of this document function lower the speed of my application?
i.e. if i have:

<><><><><><><><><><><><><><><><>
<xsl:variable name="config-top" select="document( 'names.xml' )/config"/>
<><><><><><><><><><><><><><><><>

does it act as a variable where by onces set it doesn't depend on the
availability of
names.xml document any more?