Could someone elaborate on this section

****

*Paxos Repair*
We will introduce a new repair mechanism, that can be run with or without
regular repair. This mechanism will:

   - Track, per-replica, transactions that have been witnessed as initiated
   but have not been seen to complete
   - For a majority of replicas complete (either by invalidating,
   completing, or witnessing something newer) all operations they have
   witnessed as incomplete prior to the intiation of repair
   - Globally invalidate all promises issued prior to the most recent paxos
   repair

****

Specific questions:

Assuming a table only using these LWT:s

* As the repair is only guaranteed for a majority of replicas, I assume I
can discover somewhere which replicas are up to date like this?

* Do I understand correctly, that if I take a backup from such a replica,
it is guaranteed to contain the full state up to a certain timestamp t?
(And in addition may or may not contain mutations higher than t, which of
course could overwrite the value the same key had at t.)

* Does the replica also end up with a complete and continuous log of all
writes until t? If not, does a merge of all logs in the majority contain a
complete log? In particular, I'm trying to parse the significance of "or
witnessing something newer"? (Use case for this last question could be
point in time restore, aka continuous backup, or also streaming writes to a
downstream system.)

henrik
-- 

Henrik Ingo

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