Hello -- perhaps someone could provide me some clarification about this.
From:
http://www.datastax.com/docs/1.1/dml/data_consistency#data-consistency
"If consistency is top priority, you can ensure that a read will always reflect
the most recent write by using the following formula:
(nodes_written + nodes_read) > replication_factor"
But consider this. Say I have a replication factor of 3. I request a QUORUM
write, and it fails because the write only reaches 1 node. Perhaps there is a
temporary partition in my cluster. Now, asynchronously, a different reader
performs a QUORUM read of the same cluster and just before it issues the read,
the partition is resolved. The quorum read is satisfied by the two nodes that
have *not* received the latest write (yet). Doesn't this mean that the read
does not "reflect the most recent write"? I realise this is very unlikely to
happen in practise, but I want to be sure I understand all this.
Perhaps the documentation would be more correct if the statement read as
"...reflect the most recent SUCCESSFUL write..."?
Thanks,
Philip
--
Philip O'Toole
Senior Developer
Loggly, Inc.
San Francisco, CA
