Re: main memory consumption using xalan

On 7/30/07, Lensch, Thomas <Lensch@xxxxxxxx> wrote:
> Hi,
>
> we use xalan 2.6 in an Tomcat/web-environment using the JAXP 1.3 API to
> run Xalan-Java. We transform our xml documents to generate XHTML pages.
>
> We have many types of xml data. These all are transformed by
> type-specific xsl using some standardard XSL templates. So we have the
> following (simplified) structure:
>
> Template A.xsl for type A:
>
>         <xsl:include href="includes/base.xsl"/>
>         <xsl:tempalte match="*">
>         .....do something
>
> Template B.xsl for type B:
>
>         <xsl:include href="includes/base.xsl"/>
>         <xsl:tempalte match="*">
>         .....do something
>
> and so on for about 20 types
>
> When transformation for a document of type A is done A.xsl and base.xsl
> are loaded and kept in main memory.
>
> When transformation for a document of type B is done B.xsl and A NEW
> INSTANCE of base.xsl are loaded and kept in main memory.
>
> After all we need 20 times the memory for base.xsl! So, main memory is
> wasted and we have costs to allocate this memory.
>
> Does anybody know how to avoid this behaviour?

I suspect you'll be out of luck - the various stylesheets get built
into a single Transformer so A+Base will be a separate Transformer to
B+Base and not share the parsed base.xsl in any way.

If memory is really critical and your specific stylesheets are simple,
then you can probably replace the import behaviour with a choose/when
in base.xsl, but you'd loose all of the maintainability benefits.


-- 
http://andrewjwelch.com