Greg Stark <gsstark@mit.edu> writes:
> Bruno Wolff III <bruno@wolff.to> writes:
>> Using an index to do an order by is an order N operation.
> No, using an index to do an order by is actually still n*log(n). You have to
> traverse all the parent pages in the binary tree of the index as well.
Only if you searched afresh from the root for each key, which an
indexscan is not going to do.
regards, tom lane