Does it matter if I serve sitemap.xml as a dynamic page? e.g., use .htaccess to rewrite sitemap.xml (or whatever static URL I submitted at the Webmaster Tools) to a PHP file. The PHP file will call the DB and generate the XML file on the fly.
Does it matter if I use it like this a dynamic PHP page, or should I prepare a static page? The only downside I see is the load time of the file, but it doesn't sound too important considering this page is accessed only by SE boots.