On 21/10/2010 20:03, Peter Schuller wrote:
My question is: is node E notified that it lost the battle against A? If yes
how?
If not, then it means that, although writes are atomic, they would not be
deterministic. Node E would have to verify that its write was successful...
Quorom is not really a special case in that sense; it just tells how
many nodes must ack the operation. The conflict resolution of columns
proceed as usual and data replicate as usual. Node E would do the same
conflict resolution as other nodes whenever it sees the write,
regardless of that was because it was in the original chosen quorom
set, or it was given the right a bit later in the background, or it
happened during anti-entropy etc.
OK. Thanks for your answer. From an email exchange I had with Jonathan,
all this means that one should re-read its writes with quorum to make
sure they have not been overriden by timestamp-tie conflicts. I
suggested to send feedback to writting node (in the ACK) when such
timestamps-tie conflict happen. This would avoid having to double-check
all writes for timestamp-tie conflicts.
If multiple applications write to the same ColumnFamily/Tables, this
double-check is a must (unless a separate locking mecanism is
implemented, which would be more heavy).
Jérôme
