转换XML的内存缓存的缺点？

I'm writing a web application that constantly retrieves XML "components" from a database and then transforms them into XHTML using XSLT. Some of these transformations happen frequently (e.g. a "sidebar navigation" component goes out for the same XML and performs the same XSL transformation on every page that features that sidebar), so I have started implementing some caching to speed things up.I'm writing a web application that constantly r