Accord: Add Rebootstrap and unsafe Bootstrap

[belliottsmith]

To support recovering a node that has lost some of its local transaction log, introduce rebootstrap and unsafe bootstrap modes, where Accord ensures no responses are produced for transactions the node cannot be certain it had not previously answered.

patch by Benedict and Alex Petrov for CASSANDRA-20908

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The Cassandra Jira

[ifesdjeen]

Is this implemented in some other way? I believe I had an implementation of repair plugged in here.

[belliottsmith]

This logic is also disabled for now, I plan to introduce it in a follow up patch.

[ifesdjeen]

Just for my understanding: this patch is then just to make Accord compile?

[belliottsmith]

No, it also supports bootstrapping a node that was previously bootstrapped. That said, let me see about at least restoring this part of the patch, and we can address the journal replay issue in a follow up.

[ifesdjeen]

Either way: I am also completely fine with doing this in a follow-up patch.

[ifesdjeen]

should we return false on corruption?

[belliottsmith]

This logic is essentially disabled for now as we discussed, I will introduce it more fully in a follow up patch.

[ifesdjeen]

I can not recall any conversation about this logic being disabled. Searched messages quickly and couldn't find anything either. Maybe I misunderstood when it got mentioned.

[ifesdjeen]

I'm sure you had it in mind, but just for completeness, reminding to switch branch.