Re: Xalan C++ 1.9.0 poor performance - used with Xerces 2.6.0

David, thanks for the help.
I have logged this, with files and 'Xalan -t' results for 1_9 and 1_10.

Created: (XALANC-593) Poor performance with a complex XSL stylesheet and ...

Sean

--- David Bertoni <dbertoni@xxxxxxxxxx> wrote:

> Sean Ryan wrote:
> > Hello, 
> > 
> > To reproduce this problem I think you will need my XSL and XML files.  But 
> > I don't want to
> > overload the mail list... (I already sent a massive message to the subscibe 
> > address - sorry
> about
> > this but I don't use mailing lists much).
> > 
> 
> Yes, we'll need your input files.
> 
> > The main app I have is a fairly memory hungry GUI, so I tried running the 
> > Xalan transform in
> its
> > own process,
> > this helped a bit.  
> > The performance in RELEASE is about 2 minutes.
> > The performance in DEBUG is about 30 mins.
> > This is similar to the performance of the Xalan sample 
> > 'XalanCallbackTransformer' (RELEASE 2
> > minutes, DEBUG 11 minutes).
> >
> 
> Well, the performance is 3x slower for your application with the debug 
> configuration, so that seems significant.
> 
> > 
> >>Are you by any chance using a ostrstream or ostringstream instance as to
> >>hold the result of the transformation?
> > 
> > 
> > I am using a callback handler, and it uses a vector of string objects on 
> > the heap.
> > I don't think this is related to the problem - nearly all the time is spent 
> > processing BEFORE
> > there is more than 1KB of output.
> > 
> 
> OK.
> 
> > 
> >>You cannot build Xalan-C without Xerces-C, and I'm not sure why you 
> > 
> > 
> > I got the idea from the Apache page:
> > http://xml.apache.org/xalan-c/usagepatterns.html#xercesdomwrapperparsedsource
> > 
> > "Performance is much better when Xalan-C++ uses native source tree handling 
> > rather than
> > interacting with the Xerces DOMParser".   
> > What does this mean then, if Xalan cannot be built without Xerces ?
> >
> 
> Yes, that could be clearer, but it's a comment about that particular 
> usage pattern.  It involves wrapping an instance of Xerces-C's 
> DOMDocument for use as the source tree for a transformation.  I will try 
> to re-write some of that documentation to make it a bit clearer.
> 
> > 
> >>any performance issues, so why do you think Xerces-C is the problem in 
> >>your code?
> >>
> >>Please show us some code that shows us how you are invoking Xalan-C.  In 
> >>particular, show us how you are handling the output of the transformation.
> >>
> > 
> > 
> > I believe the problem is with Xalan-C not Xerces-C, since even the sample
> > 'XalanCallbackTransformer' takes 2 minutes in RELEASE build.
> > Here is my code in any case:
> 
> Without knowing the timing breakdown of parsing the source tree, parsing 
> the stylesheet, and the actual transformation, it's hard to determine if 
> that time is excessive.
> 
> Here's the best approach, I think:
> 
> 1. Create a Jira issue and attach your source XML and stylesheet files.
> 2. Download Xalan-C 1.10 and test to see if there is any performance 
> difference with the latest version of the sample 
> XalanCallbackTransformer application.
> 3. Run your transformation with the Xalan executable with the -t option, 
> to see the timing information.  Also, make sure you redirect the output 
> to a file:
> 
> Xalan -t -o foo.out document.xml stylesheet.xsl
> 
> That will tell you exactly where the time is being consumed.
> 
> Once you create the Jira issue and attach the XML files, someone can 
> look at what's happening.  It could be your stylesheet is very complex, 
> and that's the problem.  Or, it could be your source file is quite 
> large, and it's taking a long time to parse the source file.
> 
> Dave
> 


___________
Sean Ryan