"Michel de Becdelièvre" <m_debec@msn.com> wrote in message
news:uDWAWrQXEHA.712@TK2MSFTNGP11.phx.gbl...
> I have some *performance* trouble reading MathML files in my application
(in
> ASP.Net).
>
> - I have small MathML files (2-3k) as input
> - as (almost) all MathML files these use entities. I have no way to
restrict
> the entities used.
> - to read an XML file entities into a document, you need to use a DTD, or
> you get an exception (any other way ?)
> - The MathML DTD is HUGE (2400+ Entities, ~300k of files), loading it in a
> document is a big CPU and file access hog, specially for a ASP.net
> application. As you see the DTD is easilly a hundred times bigger than the
> file to load.
>
> I tried to pay the price only once by caching an empty XmlDocument and
> reusing it as a template, but doc.Clone() is also a big CPU hog, and
trying
> :
> doc = docIn.Implementation.CreateDocument();
> XmlNode n = doc.ImportNode( docIn.DocumentType, true );
> to initialise the DTD is better but still intensive.
>
> Any ideas on a better way to handle XmlDocument with a large number of
> entities ? Pointers ? Suggestions ?
>
> Thanks in advance.
>
>
>
>
>

> Unfortunately, re-using "cached" DTD's is a tough problem, because the
> instance document can always override any part of the DTD, including
> parameter entities, by providing an internal subset, so we have not
> optimized this case.
>
> If you really need your mathml documents to be validated, you could
convert
> the DTD to XSD (using the Visual Studio 2005 XML editor) and then validate
> using a cached XmlSchemaSet. But alas, XSD does not have entities.

> So sounds like we need to work on a better solution for caching DTD
> entities, character entity sets specifically. I filed this as a work item
> for us to consider.

"Michel de Becdelièvre" <m_debec@msn.com> wrote in message
news:ORcHMbNYEHA.3568@TK2MSFTNGP10.phx.gbl...
>
> "Chris Lovett" <clovett@microsoft.com.no_spam> a écrit dans le message de
> news:eAbGgQJYEHA.1764@TK2MSFTNGP10.phx.gbl...
> > Unfortunately, re-using "cached" DTD's is a tough problem, because the
> > instance document can always override any part of the DTD, including
> > parameter entities, by providing an internal subset, so we have not
> > optimized this case.
> >
> > If you really need your mathml documents to be validated, you could
> convert
> > the DTD to XSD (using the Visual Studio 2005 XML editor) and then
validate
> > using a cached XmlSchemaSet. But alas, XSD does not have entities.
>
> I do not *really* need to validate (I'm confident on the quality of the
> MathML emitter), but I need to parse the MathML into a XmlDocument tree
> (need to be able to backtrack for instance), and I have found no way (even
> with Validation.None) to avoid parsing the entities.
>
> > So sounds like we need to work on a better solution for caching DTD
> > entities, character entity sets specifically. I filed this as a work
item
> > for us to consider.
>
> Thanks. Won't solve my problem now, but will be needed for MathML and may
be
> for XHTML.
>
>
>