If you find yourself struggling with modeling a particular problem in Cassandra, consider reimagining the model as immutable time-series data. This strategy often results in an obvious solution to what appeared to be an intractable problem.
Immutability is a desirable property in a Cassandra data model as updates and deletes can add complexity related to consistency and performance (remember that SSTables are immutable). Often the easiest way to guarantee immutability is to simply add a time component to your data model.
Immutability in Cassandra.
Share this highlighthttp://www.safaribooksonline.com/a/cassandra-high-availability/568050/