Generate Google and Google News Sitemap files for really large number of posts being stable in memory usage.
When you have a large number os posts it's impossible to create sitemaps by
using pseudocron or hooks like
save_post. This plugin will
require a system cron schedule to visit a secret URL and trigger the sitemap
It splits the sitemaps into 50,000 URLs each, and also tries to stabilize the memory usage during the run, doing small queries and using a limited buffer to write the files.
If you don't have administration privileges over your server, you can use a cron job provider on the Internet. If you do, please report your experience for the other users.