Vitess’s VStream feature was introduced in version 4.0. It is a change event subscription service that provides equivalent information to the MySQL binary logs from the underlying MySQL shards of the Vitess cluster.A user can subscribe to multiple shards in a keyspace, making it a convenient tool to feed downstream CDC processes.To read and process database changes, the Connector subscribes to VTGate’s VStream gRPC service. VTGate is a lightweight, stateless gRPC server, which is part of the Vitess cluster setup. The Connector gives you the flexibility to choose to subscribe to the MASTER nodes, or to the REPLICA nodes for change events.
Because the Connector reads change events from the VTGate VStream gRPC server, it does not need to connect directly to MySQL instances. Therefore, no special database user and permissions are needed.