Revertible, Recoverable Schema Migrations in Vitess

Recent developments in Vitess take online schema migrations to a new level, allowing us to think of DDLs as little more than a transaction, giving both developers and DBAs new super powers and peace of mind. – Have you ever completed a schema migration only to realize a column should not have been dropped, an index should not have changed? – Have you ever dropped a table only to find it was a big mistake? – Have you ever waited a week for a schema migration, only to see it go down the drain due to a failover? Or have you postponed important maintenance work due to a running migration? Vitess online schema migrations now utilize _VReplication_, a core component in Vitess that empowers Vitess’s live resharding, materialized views, live imports, and more. In this session we present VReplication and illustrate how it works. We follow up to explain how online schema changes employ VReplication for both revertible, and recoverable, lossless schema migrations. We will discuss some of the internal logic, and present a demo of these new super powers. Vitess is a CNCF open source database clustering system for horizontal scaling of MySQL. Speaker: Shlomi Noach – Planet Scale