[转]Cassandra的 Consistency Level设置，

[转]Cassandra的 Consistency Level设置，

转自：http://blog.csdn.net/lzz313/article/details/5457313
原文出处不详

写操作

级别	内容
ZERO	Ensure nothing. A write happens asynchronously in background
ANY	(Requires 0.6) Ensure that the write has been written to at least 1 node, including hinted recipients.
ONE	Ensure that the write has been written to at least 1 node's commit log and memory table before responding to the client.
QUORUM	Ensure that the write has been written to <Replication> / 2 + 1 nodes before responding to the client.
ALL	Ensure that the write is written to all <Replication> nodes before responding to the client. Any unresponsive nodes will fail the operation.

读操作

级别	内容
ZERO	Not supported, because it doesn't make sense.
ANY	Not supported. You probably want ONE instead.
ONE	Will return the record returned by the first node to respond. A consistency check is always done in a background thread to fix any consistency issues when ConsistencyLevel.ONE is used. This means subsequent calls will have correct data even if the initial read gets an older value. (This is called read repair .)
QUORUM	Will query all nodes and return the record with the most recent timestamp once it has at least a majority of replicas reported. Again, the remaining replicas will be checked in the background.
ALL	Will query all nodes and return the record with the most recent timestamp once all nodes have replied. Any unresponsive nodes will fail the operation.