[xquery-talk] FLOWR vs Xpath axis syntax - Performance

[Michael Kay]

On 31/07/2012 17:25, Ihe Onwuka wrote:
> I vaguely remember reading somewhere that a preference for what I
> would call axis notation has performance advantages over the
> equivalent FLOWR code.
>
> I certainly recall reading that  XPath predicates perform better than
> where clauses in FLOWR.
>
> I would appreciate clarification, confirmation or correction and
> general enllightenment.
As others have said, this is likely to vary between implementations.

I know that some implementations attempt to rewrite FLWOR expressions as 
path expressions, while other implementations try to do the opposite. 
Presumably in such implementations, if the rewrite succeeds, then it 
doesn't matter which way you write the query.

Do some measurements, and share the results with the list, then we can 
all be enlightened.

Michael Kay
Saxonica