Posting in the Magento forums has been disabled pending the implementation of a new and improved forum solution which should better serve the community.
For new questions please post at magento.stackexchange.com, the community-run support site for the Magento community. We will be providing updates on the new forum solution soon. For questions or concerns please email firstname.lastname@example.org.
If it would take that many sku’s it would take forever to import into the database if it does not crash… I can only import 5 sku’s per minute. So that is about 7200 sku’s in 24 hours or about 69 days for 500,000 sku’s. Importing speed must get better before I can see going live with a Magento web store.