Percona and pt-online-schema-change is not just "some third-party library". It's an industry-standard tool and one of the most respected forks of MySQL. It's n

Percona and pt-online-schema-change is not just "some third-party library". It's an industry-standard tool and one of the most respected forks of MySQL. It's not a layer of maintenance problems and they sell commercial support. Their customers include the BBC, Yelp, and Cisco: http://www.percona.com/about-us/customers http://www.percona.com/about-us/customers Also, for the record, Oracle added online schema changes in 5.6.