What is Migration (database system)?

The process of migrating the entire database from one system to another (e.g. From MySQL to PostgreSQL or vice versa). The process usually consists of 3 phase, 1) baseline phase 2) catchup phase 3) switchover phase. In the baseline phase, team creates a data dump from the source database system and loads it into the target database system. 2) In the catchup phase, team configures a change-data-capture (CDC) pipeline to stream the ongoing changes to the target database. 3) In the switchover phase, team cuts off the traffic to the original database, wait for target database to catch up all new changes from the source database, and then redirect the traffic to the target database. If executed carefully, the downtime would be limited to the blackout period in the switchover phase.