XMLDocument.Load() performance

[John A Grandy]

I've got an app that has hundreds of medium-sized (100s of elements) XML
files on disk (not in db). Right now these are loaded via XMLDocument.Load
and searched with XPATH.

The performance has become unacceptable.

Performance improvment strategies I know of:

1. Switching to XMLReader

2. general System.XML 2.0 speed improvements

3. SQL Server 2005 : putting the XML in the XML Data Type and :
(a) doing XPATH directly against the DB
(b) loading the XML from the DB into an XMLDocument and doing XPATH against
it

Can anyone provide more information? What type of speed improvements can be
expected?

I've read that with System.XML 1.0 you can expect about 30-40% improvement
by switching to XMLReader techniques.

[Oleg Tkachenko [MVP]]

John A Grandy wrote:

I've got an app that has hundreds of medium-sized (100s of elements) XML
files on disk (not in db). Right now these are loaded via XMLDocument.Load
and searched with XPATH.

The performance has become unacceptable.

Performance improvment strategies I know of:

1. Switching to XMLReader

2. general System.XML 2.0 speed improvements

3. SQL Server 2005 : putting the XML in the XML Data Type and :
(a) doing XPATH directly against the DB
(b) loading the XML from the DB into an XMLDocument and doing XPATH against

XmlReader doewsn't support XPath queries. Switch to System.XML 2.0 is
certanly a good idea.
Usual optimizations are:
1. Use XPathDocument instead. It's 30-50% faster than XmlDocument when
it comes to XPath or XSLT, because it's explicitly optimized for XPath
queries.
2. Optimize your XPath expressions. Never use "//" but "descandant::"
instead etc.
3. If your queries are homogeneous you can get amazing performance boost
by indexing XML in-memory using IndexingXPathNavigator, see
http://msdn.microsoft.com/XML/Buildi...MLindexing.asp
4. If you can limit XPath to forward only subset, you can use
XPathReader, which is XPath-aware XmlReader.

--
Oleg Tkachenko [XML MVP, MCAD]
http://www.xmllab.net
http://blog.tkachenko.com