I ran into this problem with MySQL. We have a table of user submissions that is millions of rows but the amount of time it was taking to migrate the test server

I ran into this problem with MySQL. We have a table of user submissions that is millions of rows but the amount of time it was taking to migrate the test server was unacceptable downtime in production. We ended up using https://www.percona.com/doc/percona-toolkit/2.1/pt-online-schema-change.html https://www.percona.com/doc/percona-toolkit/2.1/pt-online-sc... to do an online update.