RE: [xml-dev] XML-enabled databases, XQuery APIs

From
Michael Kay <>
To
"'Bullard, Claude L (Len)'" <>, 'Michael Rys' <>, 'Ronald Bourret' <>
Date
2005-04-18T18:43:08Z
Thread
RE: [xml-dev] XML-enabled databases, XQuery APIs
> 
> 1)  The effect of the binary is to increase the parser space. 
> The relational system doesn't care because it uses an internal 
> representation.
> 
> However, the binary is reputed to create a faster parse.

I would be very surprised if XML parsing contributes anything noticeable to
the cost of a database load (in shredding mode). Except possibly for a
pathological XML document containing 3 nodes and 3 billion bytes.

I haven't looked at the latest products from MS or Oracle, but my experience
of database loading with complex data and a realistic level of indexing is
that it's a couple of orders of magnitude slower than XML parsing. You can
improve that with a custom loader that bypasses SQL and does a lot of
heavy-duty sorting and merging to minimize head movement on the disk (does
anyone still do that?), but I think it's still true that the parsing cost is
immaterial.

Michael Kay
http://www.saxonica.com/