Cassandra does not support TTL function on collections, and returns null when apply TTL function on non-frozen UDT.
But "using ttl nnn" is able to be used to insert or update collections and non-frozen UDT.
1. are ttl values obeyed for collections and non-frozen UDT?
2. Why TTL function is not able to apply to collections
3. Why TTL function returns null for non-frozen UDT?