Comparison
CRDTvsLast-write-wins
CRDT
two replicas both took offline edits and merged them without a conflict, because the data type only supports operations that commute.
A data structure whose merge is associative, commutative and idempotent, so replicas converge regardless of the order updates arrive in. It removes conflict resolution as an application concern for the shapes it supports — counters, sets, sequences. The constraint is that your semantics must fit one of those shapes; arbitrary business invariants do not.
Full entry →Last-write-wins
two writes to the same key conflicted and the system kept the one with the later timestamp and silently threw the other away.
A conflict resolution strategy that compares timestamps and discards the loser. It is simple, requires no application logic, and loses data by design. It is also only as good as the clocks involved, which on separate machines are not as synchronised as the strategy assumes.
Full entry →