On Wed, Jul 3, 2013 at 6:02 AM, Hiller, Dean <Dean.Hiller@nrel.gov> wrote:
> We loaded 5 million columns into a single row and when accessing the first 30k and last 30k columns we saw no performance difference. We tried just loading 2 rows from the beginning and end and saw no performance difference. I am sure reverse sort is there for a reason though. In what context do you actually see a performance difference with reverse sort???
When a query does not specify a start column (and does not specify reversed) the server can just start reading columns from the start without having to worry about finding the right place to start. This is exactly what we can do for the Descending CF.
For the regular Ascending CF we need to specify reversed, so the server must read the row index and work out which column is column count from the end of the row.
There is no comparison really.