2) migration involves the problem of mixing a migration write with an actual live in flight mutation. Cassandra would solve this with additional per cell write time tracking or a migrated vs new mutation flag
3) and then you have deletes. So you'll need a tombstone mechanism, because if a live delete of a cell value is overwritten by a migrated value, than data that is deleted comes back to life
2) migration involves the problem of mixing a migration write with an actual live in flight mutation. Cassandra would solve this with additional per cell write time tracking or a migrated vs new mutation flag
3) and then you have deletes. So you'll need a tombstone mechanism, because if a live delete of a cell value is overwritten by a migrated value, than data that is deleted comes back to life