restatedev
Invocation epoch
Followup of #2891, part of #2890.
This implements the InvocationEpoch mechanism, as described in #2890.
Moreover, what's not fully clear to me is how the invocation epoch will work during a rolling upgrade where one node is running on an older version and does not know about the invocation epoch and the caller is using it. Would this pose a problem if the response is sent back to the caller with 0 as the invocation epoch and then potentially being ignored?
It simply doesn't work. You can't use the new trim and restart feature unless you're 100% sure you're using the new restate version, that's the constraint.
It simply doesn't work. You can't use the new trim and restart feature unless you're 100% sure you're using the new restate version, that's the constraint.
So should this feature by default disabled with the next version unless users explicitly enable it in the configuration which states that they should only use it if all their nodes have upgraded to the next version and they forfeit being able to go back to an earlier version?
So should this feature by default disabled with the next version unless users explicitly enable it in the configuration which states that they should only use it if all their nodes have upgraded to the next version and they forfeit being able to go back to an earlier version?
I guess we can, but we can also defer this decision to a later point IMO.
I guess we can, but we can also defer this decision to a later point IMO.
If so, then please create a release blocker issue for the next release. I would, however, advise against postponing making a decision for too long because it will otherwise bite us when we have/want to create a quick release.
I also wanted to ask what's the plan with how to enable/disable this feature to prevent users from shooting themselves in the foot if the time travel during a rolling upgrade. Are you gonna address in the PR where you introduce the time travel feature?
I'm not sure yet. For the time being let's move on this PR, i'm gonna check with @igalshilman about this. This intersects with how we wanna present it in the UI too (it would be bad if we show in the UI the button but then it fails because some config option is not enabled).