> 1) In the case of a network partition, the client that is currently connected to the leader, do they get notified that there's a partition, or that the cluster is not in a healthy situation?
The cluster - or any server of the cluster - finds out about network partition only when the timeout passes. At this point the leader - which becomes the former leader - can notify the client, or the client can see for itself that the timeout has passed.
> 2) If a client writes to the partition that will get rolled back, and all their transactions get rolled back after the partition heals, do they get notified that their data was rolled back?
Note that the client was never notified that their data was committed in the first place. So the client can assume that if the timeout passed without notification that the data wasn't set in the cluster.
Surely there could be problems between the client and the leader. Idempotent messages could be useful.
The cluster - or any server of the cluster - finds out about network partition only when the timeout passes. At this point the leader - which becomes the former leader - can notify the client, or the client can see for itself that the timeout has passed.
> 2) If a client writes to the partition that will get rolled back, and all their transactions get rolled back after the partition heals, do they get notified that their data was rolled back?
Note that the client was never notified that their data was committed in the first place. So the client can assume that if the timeout passed without notification that the data wasn't set in the cluster.
Surely there could be problems between the client and the leader. Idempotent messages could be useful.