gh-ost
GitHub's online schema migrations for MySQL
gh-ost is a triggerless online schema migration solution for MySQL. It is testable and provides pausability, dynamic control/reconfiguration, auditing, and many operational perks. gh-ost produces a light workload on the master throughout the migration, decoupled from the existing workload on the migrated table. It has been designed based on years of experience with existing solutions, and changes the paradigm of table migrations. All existing online-schema-change tools operate in similar manner...