The quorum write would fail, but the data would not be rolled back. Assuming the offline nodes recover, the data would eventually replicate.
This question belongs on the user list, though. -----Original Message----- From: Maifi Khan <maifi.k...@gmail.com> Date: Thu, 19 Aug 2010 13:00:47 To: <dev@cassandra.apache.org> Reply-To: dev@cassandra.apache.org Subject: questions regarding read and write in cassandra Hi I have a question in the following scenario. Say we have 10 nodes, Replication factor is 5. Now, say, for Row X, Column Y, data is replicated to node 1,2,3,4,5 and current value is 10 Say, I issue a write command with value “20” to Row X, column Y with quorum(n/2+1=3 nodes). Say it updated 1 and 2 and failed to update any other node. So it failed to write to 3 nodes. What happens in such scenario? Q: Will the user returned failed? Now, assuming that the write failed. What value will I see if I want to read the same cell with Quorum? Now, say I read the data with quorum. It read from 1, 4, 5 and see that node 1 has the most recent data (“20” which is still there as cassandra does not roll back). Will it will return the data “20” to the user or will it return the earlier value 10 as it is returned by the node 4 and 5? Also, does read repair tries to propagate 20 to all the replicas although cassandra returned failed to the user? thanks
