On Sat, Sep 3, 2011 at 8:26 PM, Kevin Burton <burton@spinn3r.com> wrote:
The point is that replication in Cassandra only needs timestamps to handle out of order writes … for values that are idempotent, this isn't necessary.  The order doesn't matter.

I believe this is a mis-understanding of how idempotency applies to Cassandra replication. If there were no timestamps stored, how would read-repair work? There would be two different values with no way to tell which was written second.