What is the ConsistencyLevel value? Is it ConsistencyLevel.ANY? Javadoc: * Write consistency levels make the following guarantees before reporting success to the client: * ANY Ensure that the write has been written once somewhere, including possibly being hinted in a non-target node. * ONE Ensure that the write has been written to at least 1 node's commit log and memory table * QUORUM Ensure that the write has been written to <ReplicationFactor> / 2 + 1 nodes * LOCAL_QUORUM Ensure that the write has been written to <ReplicationFactor> / 2 + 1 nodes, within the local datacenter (requires NetworkTopologyStrategy) * EACH_QUORUM Ensure that the write has been written to <ReplicationFactor> / 2 + 1 nodes in each datacenter (requires NetworkTopologyStrategy) * ALL Ensure that the write is written to <code><ReplicationFactor></code> nodes before responding to the client.
发件人: Roshan Dawrani [mailto:roshandawr...@gmail.com] 发送时间: 2011年1月25日 10:57 收件人: user@cassandra.apache.org; hector-us...@googlegroups.com 主题: Basic question on a write operation immediately followed by a read Hi, I have a basic question - maybe silly too. Say, I have a 1-node Cassandra setup (no replication, eventual consistency, etc) and I do an insert into a column family and then very close in time to the insert, I do a read on it for the same data. Is there a possibility that my read operation may miss the data that just got inserted? Since there are no DB transactions in Cassandra, are writes immediately seen to readers - even partially as they get written? Or can there be a delay sometimes due to flusing-to-SSTables, etc? Or, the writes are first in-memory and immediately visible to readers and flusing, etc is independent of all this and happens in background? Thanks. -- Roshan Blog: http://roshandawrani.wordpress.com/ Twitter: @roshandawrani<http://twitter.com/roshandawrani> Skype: roshandawrani
