Bug Report: Tablets in `RESTORE` and `BACKUP` cause SwitchTraffic to fail about vitess

[mattlord]

Thank you for the detailed issue @TonySparc ! There isn't currently a well defined behavior here — other than the code which will effectively not switch traffic if you have "interim" tablet types like this — so it's unclear if this is a bug or a feature request (technically it would be a feature request, but I can understand how it can be seen as a bug and we could potentially treat it that way).

I would lump this in with the general issue that VReplication does not currently have any special handling for tablet types other than primary, replica, and rdonly — again, other than that they can't exist at the time we switch traffic.

We can't really just go ahead and switch traffic because that tablet could become a replica or rdonly table, right? What does it mean to be backing up or restoring a tablet for a shard that is about to become non-serving (at least for a set of tables)? This is certainly simpler for MoveTables as both sides of the move have serving tablets, it's just a matter of what tables they are serving. Can you please explain in detail what you expected here and what you would prefer? You detailed what happened and the practical impact it had on you, and I understand that, but there are tradeoffs and potential issues in changing the current behavior.

It may very well end up that, at least for MoveTables, we can simply ignore these tablet types. But I wanted to dig in a bit before considering fixes for the issue.

Thanks again!