> I am using the familiar meanings from ACID: > > atomic means either the entire update will succeed or none of it. > > isolated means other threads will not see partial updates while it is > being applied.
A related concern is whether there is a write *ordering* guarantee for mutations within a row key. Ensuring consistency in the face of concurrent access can in some (probably several) cases become a lot easier with an ordering guarantee which would otherwise necessitate an RPC call between potentially every mutation (depending on where dependencies between writes are). Upon cursory inspection it *seems* to me that ordering is maintained, but even if this is correct, can one consider Cassandra to have such an ordering guarantee or is any such behavior an artifact of current implementation details? By ordering guarantee I am only thinking of single column reads or distinct get_slice() calls; I am not expecting ordering guarantees w.r.t. visibility within a single get_slice(). (Additionally I am assuming QUOROM or RF=1, else it would not be useful to rely on anyway.) -- / Peter Schuller
