If you can use an ORM to run a migration on your database, then scaling is not your issue. But when you're dealing with terabytes of data or more with hundreds

If you can use an ORM to run a migration on your database, then scaling is not your issue. But when you're dealing with terabytes of data or more with hundreds or thousands of concurrent queries short-and-long, you're going to have a bad time running a naïve tools migration scripts.