A)About the file size

I agree that if I allocate more memory to the JvM
Saxon will work with my 16MB file.

But 16MB is just a test before
using 1GB file trace & more

As my XML trace files are completely flat,
I was wondering why Nux + Saxon can process these files
and XQJ+ Saxon cannot.

Tell me if I'm wrong but I've the feeling that
Saxon (when used with Nux) does not directly work over the whole file
but just over a part that has been extracted by a SaX/Stax parser.

B)About speed

Concerning the speed issue for the 16Mb file processing, my mean measurement over 10 xquery are:
a)A simple xerces parser with equivalent Xquery code : 1sec per query
b)Nux/Saxon with Stax with pure Xquery : 2,5sec per query
c)Nux/Saxon with Sax with pure Xquery : 4 sec per query

I believe that the 1,5 overhead sec of b) compared to a) is not to bad (good indeed)
but I hope to win an other 0,7 sec with optimization.

A rapide profiling of the code shows that the time consuming parts
are the wrappings (Nux/Saxon) over the stax parser.

Is a smart tuning of saxon/nux through get/set functions possible?
If not, is there a direction (even a little bit more complex) to speed up my application:
Discarding Nux or Saxon (but keeping xquery) or using something else?

Thanks for your time