Can we not implement counts by just storing all the deltas in a row, and then summing them all up to acheive a count.
If a row ends up with too many deltas, a reader could just summarise the
deltas occasionally into a single value (in a way which avoids race
conditions, of course).
So you'd map
key => { uniqueid: delta1, uniqueid: delta2 }
Every column in Cassandra also has a timestamp, so your app can decide, when
it does a read, which deltas to summarise.
Mark
