For MySQL we use github's tool gh-ost https://github.com/github/gh-ost https://github.com/github/gh-ost There is a few tech restrictions, but if your database m

For MySQL we use github's tool gh-ost https://github.com/github/gh-ost https://github.com/github/gh-ost There is a few tech restrictions, but if your database meets that it works great. I migrated huge tables with absolutely no impact on production