Subject: [xsl] The benefits of exact selection From: Jesper Tverskov <jesper@xxxxxxxxxxx> Date: Fri, 6 Nov 2009 12:21:49 +0100 |
Hi list We always hear that we should select as exactly as possible, and that wildcards are inefficient. It makes sense. But I'm tired of just telling it to my students so I set out to construct a little transformation test that can demonstrate it in the classroom. I ended up with a million lines subdivided into 1050 children, each having 140 children, each having 3 children. In what I believe is the last element in document order, I might be wrong, I added a lonely attribute with some value. The two alternative select expressions are as follows: 1) <xsl:value-of select="/document/colors[1050]/color[140]/dec/@num"/> and 2) <xsl:value-of select="//@num"/> Using Saxon PE from inside Oxygen, I transformed 20 times for each. Here is the average time as reported by Oxygen: 1) Exact selection: 4.1s 2) Wildcard selection: 5.0s That is a difference. But it is also fair to say that for most transformations, on a small dataset, it will be impossible to measure a difference of any importance. I would like to know about real life cases where removing not necessary wildcard matching improved the transformation speed? Cheers Jesper Tverskov http://www.xmlkurser.dk http://www.xmlplease.com
Current Thread |
---|
|
<- Previous | Index | Next -> |
---|---|---|
Re: [xsl] How to code with relative, Martin Honnen | Thread | Re: [xsl] The benefits of exact sel, James A. Robinson |
Re: [xsl] decimal vs double value s, Wolfgang Laun | Date | Re: [xsl] The benefits of exact sel, James A. Robinson |
Month |