Schema changes at scale must keep the data accessible and cannot block any clients from using a table. TiDB, a distributed MySQL compatible database, solves this by transitioning through compatible states, so clients can transition to the new state asynchronously and continue to use the data.
PingCAP, the developers of TiDB, has evolved the schema changes implementation to be both faster and more tuneable, which will be shown in the presentation.
The presentation will explain things like why a delete only state is needed, also how something like REORGANIZE PARTITION can be executed online without blocking. New development like generating and ingesting SST files for speeding up data reorganization for ADD INDEX and distributing the data reorganization load.
Speakers: Mattias Jonsson