All of our queries return data in descending order by default because that is how the data is stored on disk. It is more intuitive to return data in ascending order by default. Right now we have some queries that do return data in ascending order but not all of them.
We probably want to do the sorting in application code because many of our queries may eventually become multi-partition queries which will require sorting in application code since the query results may arrive out of order.
This should be implemented in the core API, and we ought add support for specifying sort order as well.