VStream is a change notification service accessible via VTGate. The purpose of VStream is to provide equivalent information to the MySQL binary logs from the underlying MySQL shards.
gRPC clients, including Vitess components like VTTablets, can subscribe to a VStream to receive change events from other shards. The VStream pulls events from one or more VStreamer instances on VTTablet instances, which in turn pulls events from the binary log of the underlying MySQL instance.
This allows for efficient execution of functions such as VReplication where a subscriber can indirectly receive events from the binary logs of one or more MySQL instance shards, and then apply it to a target instance.
