Re: [xsl] Saxon .Net API performance

[Michael Kay <mike@xxxxxxxxxxxx>]

 That's a very broad question!

I think probably the most important advice is to use Saxon's native tree 
model rather than running over the Microsoft DOM (which is possible, but 
slow). Most of the other things one can say are pretty generic, applying 
equally to any XSLT processor.

It's worth bearing in mind that the Microsoft System.Xml.Xsl processor 
is one of the fastest in the business. Conversely, Saxon on .NET is 
cross-compiled from Java and this creates an overhead of about 25%. If 
you take an XSLT 1.0 stylesheet that works on System.Xml.Xsl and run it 
unchanged on Saxon, it will probably be slower - not catastrophically 
slower, but a bit. Another reason for that is that Saxon is optimized 
for running XSLT 2.0, and some of the "backwards compatibility" features 
are significantly slower than their 2.0 equivalents. So an important way 
to get the best out of Saxon when you make the move is to take maximum 
advantage of XSLT 2.0 and XPath 2.0 features. For example, declaring the 
types of your variables and parameters gives the Saxon optimizer much 
more information to play with.

The other piece of advice I have to give quite often is that just 
because you have a performance problem and are using XSLT doesn't mean 
you have an XSLT performance problem. I usually find that when I look at 
overall system performance, XSLT transformation plays a rather small 
role. Often the bottleneck is in preparing the source data for XSLT 
processing, or in handling of the XSLT result data.

On the other hand, I sometimes look at a stylesheet and improve its 
performance a hundredfold by changing a few lines of code - in a way 
that is completely independent of which XSLT processor you are using. 
The moral is, don't worry about tuning your use of the XSLT processor 
API until you are confident that's where the potential is for overall 
improvement.

Michael Kay
Saxonica

On 31/08/2010 6:45 PM, Merrilees, David wrote:
> Hi
>
> I'm trying to show the performance difference we could achieve by moving to Saxon .Net API from Microsoft's XSLT 1.0 processor. Does anyone have any tips how I can get the best performance from the Saxon .Net API?
>
> Thanks
>
> David
>
>
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