On Sun, Sep 28, 2014 at 12:32 PM, Adam Retter <[email protected]> wrote:
> > I have sequence A consisting of the numbers 0 to 4000000 and sequnce B > > consisting of about 100k random I numbers within the range of sequence A > and > > I want the outer join where sequence B is "null". > > There is no 'null' in XQuery, so I am not quite sure what you mean > here. If you ware looking for all values that appear in sequence A and > sequence B, then you can do the following - > > $a[. = $b] > > I meant null in the SQL sense of outer join - sorry. I want to drop the things that are in B from A where both B and A are just sequences of integers. In other words, don't fetch what I've already got. > > > Should one expect bad performance in sequence B is not sorted and can one > > expect reasonable performance if it is? > > I think that question is very implementation specific. If all of your > data is in RAM, as your dataset is relatively small and these are just > numbers, I would expect performance to be excellent. I am not sure > that sorting will make much of a difference, but it depends on the > implementation and how it initiates the search for a false comparison > in a large sequence. > > that's good - the nightmare scenario is a O^n2 algorithm if B is not sorted
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