[xquery-talk] From map entry pairs to a pair of arrays

W.S. Hager wshager at gmail.com
Sun Jul 16 12:51:21 PDT 2017


Hi Christian,

The difference between C and Assembly is a lot smaller than between C and
XQ, and I think memory management should not be taken lightly (I'm not
saying you do). In OP's case, I believe keys could be discarded while
memory layout remains intact.

Cheers,
Wouter

Op 16 jul. 2017 12:52 schreef "Christian Grün" <christian.gruen at gmail.com>:

Hi Wouter,

In my experience, XQuery maps can be surprisingly efficient, even if
millions of items need to be processed. Obviously, no programming
language solves all problems best, though (even today, an assembler
language can a better choice than C).

Did you come across particular use cases in which it turned out that
XQuery maps and arrays were not the best choice? What do you believe
was the critical factor (memory consumption, runtime, …)?

Cheers,
Christian




On Sun, Jul 16, 2017 at 12:08 PM, W.S. Hager <wshager at gmail.com> wrote:
> Fact of the matter is that if a low level optimization can be made, it
must
> be made outside of XQuery. I assume it happens all the time. But sure, it
> depends on the use case.
>
> Op 15 jul. 2017 22:47 schreef "Michael Kay" <mike at saxonica.com>:
>
>>
>> Obviously this operation could be implemented in the host language to
make
>> it truly efficient.
>
> Don't assume that other languages are inevitably more efficient than
XQuery.
>
> And don't assume that the cost of moving/converting data from one
> programming language to another is negligible.
>
> Michael Kay
> Saxonica
>
>
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