Daniel,
     Can you provide more information (an example would be very nice) on using batch_mutate deletes to build a time-series store in Cassandra?  I have been reading up on batch_mutate from the Wiki:

http://wiki.apache.org/cassandra/API

It seems to me that since the outer map of mutation_map maps key to the inner map, it would be removing old data associated with the keys provided.  Is it possible to remove old data based on time stamp for all keys?  Is it also possible remove old keys if there has been no new data associated with it?

Bill


On Mon, Mar 8, 2010 at 8:44 AM, Daniel Lundin <dln@eintr.org> wrote:
A few comments on building a time-series store in Cassandra...

Using the timestamp dimension of columns, "reusing" columns, could prove
quite useful. This allows simple use of batch_mutate deletes (new in
0.6) to purge old data outside the active time window.