On Fri, Nov 19, 2010 at 09:04:30AM +0000, Michael Kay scripsit:
> I think Saxon-EE will automatically optimize this join for you and
> run it in O(n log n) time.

That might be straightforward; I shall try that first. :)

> Or you could hand-optimize it by running in XSLT and using keys.

I don't know how to declare a key over a collection, and I need to run
this over all the files, rather than each file.

> Both these techniques will use more memory, something which is
> probably in short supply; if you need to optimize memory consumption
> as well as execution time then you could consider some kind of
> filter/sort/merge process, which might be a lot more complex to
> write.

The machine I'm running this on has 8 GB of RAM.  I shall hope that's
enough.

Thank you!
Graydon