I was running the XML Sitemap generator from command line PHP (usr/bin/php-cli) earlier today and it ran up until getting an out of memory error. I have 2GB of memory allocated to PHP, so I don't think it should consume more resources than that. The site it's running on is [external links are visible to admins only], which is heavily interlinked.
Now I can't get it to run from command line or from the interface at all. On the interface, I don't see an option to run on the Crawling tab. When I run using /usr/bin/php-cli, then it stops after a few seconds. When I run using /usr/bin/php, then it stops with an HTTP 500 Server Error after a few seconds. However I can't see the error in my PHP error log.