Using clustering order
You can order query results to make use of the on-disk sorting of columns. You can order results in ascending or descending order. The ascending order will be more efficient than descending. If you need results in descending order, you can specify a clustering order to store columns on disk in the reverse order of the default. Descending queries will then be faster than ascending ones.
The following example shows a table definition that changes the clustering order to descending by insertion time.
create table timeseries ( event_type text, insertion_time timestamp, event blob, PRIMARY KEY (event_type, insertion_time) ) WITH CLUSTERING ORDER BY (insertion_time DESC);