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RE: transform optimization for a schema-constrained domain
- To: "'xsl-list at lists dot mulberrytech dot com'" <xsl-list at lists dot mulberrytech dot com>
- Subject: RE: [xsl] transform optimization for a schema-constrained domain
- From: "Huebel, David" <dhuebel at pointserve dot com>
- Date: Wed, 25 Jul 2001 20:05:59 -0500
- Reply-To: xsl-list at lists dot mulberrytech dot com
I became curious about this because for a each type of output I produce, I
have a single stylesheet that transforms several types of documents.
In most cases, the generic stylesheet is very readable and maintainable but
very inefficient. I could optimize performance by creating a different
stylesheet for each type of input document, but that would multiply the
creation and maintenance overhead on the stylesheets. Hence my desire to
automatically optimize a transform for a given schema. Are there any other
tricks that help in this situation?
David
-----Original Message-----
From: Michael Kay [mailto:mhkay@iclway.co.uk]
Sent: Wednesday, July 25, 2001 12:13 PM
To: xsl-list@lists.mulberrytech.com
Subject: RE: [xsl] transform optimization for a schema-constrained
domain
The Tamino XML database (from Software AG) uses schema knowledge to optimize
queries against a database (the queries are currently written in a language
that's somewhere between XPath and XQuery). But this is a rather different
scenario, because the database can do a lot of work at document loading time
to set up metadata that's useful at query time. An XSLT processor generally
has only raw XML as its input, so there's a real risk that optimisation time
will exceed transformation time - especially if it means reading and
analysing a schema.
Another problem is that you can't bind a stylesheet to a particular schema
at the time it is compiled - though I guess one could get around that.
In short, I don't think anyone is doing this in an XSLT processor today. I
might be wrong, of course.
Mike Kay
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