Can't see anything obviously problematic in this. Saxon eats it in about
120ms.
Michael Kay
-----Original Message-----
From: poppe chris [mailto:pc_poppe(_at_)hotmail(_dot_)com]
Sent: 10 May 2004 21:48
To: jeni(_at_)jenitennison(_dot_)com
Cc: xsl-list(_at_)lists(_dot_)mulberrytech(_dot_)com
Subject: Re: [xsl] problem: recursive templates slowing xalan
processor down
Hi Chris,
im having a peculiar problem, ive made a xsl stylesheet
that uses a
recursive template. When i use xmlspy to perform the xsl
transformation on a sample xml file everything works
fine, but when
i use a xalan processor (org.apache.xalan.xslt.Process) the
recursive template seems to freeze the processing. First I pass
about 15 nodes to the template wich then calls itself
with one node
less. and so on. In the beginning it goes fast but after
3 recursive
calls everything slows down and finally looks like its frozen (in
fact i still get some output but only after very long
times). Is it
possible that several recursive calls freeze the processor and how
come everything works with the xmlspy debugger??
I don't know which processor the XML Spy debugger uses, but it might
be that it rewrites (tail) recursive calls into a loop and thus deals
with the recursion more efficiently than Xalan.
Having said that, Xalan is normally pretty good at that kind of
optimisation. (Perhaps you're using an old version? Check which
version you're using with system-property('xsl:version').) Seeing a
slowdown after only three recursive calls sounds quite severe.
Can you show us your recursive template? Perhaps there are some
rewrites that could help speed it up...
Here is a link to the xslt file
http://www10.brinkster.com/cpoppe/misc/MCTFbit.xsl
And a link to a sample xml file
http://www10.brinkster.com/cpoppe/misc/coastlittle.xml
What this pretty much does is select all the substream
elements in the xml
file, then read in a length ( part of a list) and take the
sum over these
values. Ive left a number of things out of the xslt im using
but this one
still gives the same problems, starting with 15 nodes then 14
, 13 and 12
(and slowing down and once it gets to 11 or even 10 times
take that much
time it seems its frozen)
Im not looking for a completely alternate solution cause ive
reduced the
sample xmlfile and the xslt a lot. Just an explanation would
be helpfull a
lot!
Ive noticed that when i call the calcPart1 template for the
first time with
.../m:substream[last()] (so i only pass about 5 nodes to the
template)
everything goes smooth.
Here is a link to this xslt file
http://www10.brinkster.com/cpoppe/misc/MCTFbit.xsl
sincerely,
Chris
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