Re: [xsl] improving performance in creating ids

["Pieter Lamers pieter.lamers@xxxxxxxxxxxx" <xsl-list-service@xxxxxxxxxxxxxxxxxxxxxx>]

Hi Martin,

Thanks for your quick reply. the node identity comparison helped quite a 
bit, although I am still around a minute for a full book of ids. I am 
not sure how xsl:number would help here, and what kind of performance 
win it would give over count(). I tried something with a nested 
transformation, but what should I feed it?

B B B  <xsl:number select="*[last()]"/>
works (given a set of preceding nodes) but it is slightly slower than a 
count() in the xquery. Maybe I should be using xsl:number differently?

however, your suggestion of nesting transformations also opens the door 
to using generate-id() in the xquery realm, with a nested 
transformation, thereby sidestepping the problem that eXist returns 
something different for generate-id() from Saxon (also in reply toB  Dave 
Pawson).

I will see where that gets me.

tx
Pieter


On 23/04/2019 14:19, Martin Honnen martin.honnen@xxxxxx wrote:
> On 23.04.2019 14:07, Pieter Lamers pieter.lamers@xxxxxxxxxxxx wrote:
> > Hi All,
> >
> > I need generated-ids on elements in a BITS file that have @rids, so I
> > can link back to them. I cannot use generate-id(), because I need it to
> > produce the same id in both the xquery (eXist) context and in the XSL
> > (saxon) contect.
> >
> > I have created a function that will generate a human readable id based
> > on the id of the nearest ancestor/@id and then element-name + sequence
> > number. It produces the output that I like, but at the cost of a poor
> > performance (when run on a whole book) . now with the preceding/ancestor
> > juggling that I do there might be a better way than mine, so my question
> > is if there is a better way to tackle this problem.
> >
> > My function:
> >
> > declare function local:get-id-in-doc ( $target as element() ) as 
> > xs:string
> > {
> > B B  let $current-element as xs:string := local-name($target)
> > B B  let $ancestor-with-id as element()? := $target/ancestor::*[@id][1]
> > B B  let $prefix as xs:string? := $ancestor-with-id/@id/string()
> >
> > B B  let $count :=
> > B B B B  if($prefix) then
> > B B B B B B  (: case 1: there is an ancestor with an @id :)
> > B B B B B B  count($target/preceding::*[local-name() eq
> > $current-element][ancestor::* = $ancestor-with-id]) + 1
>
> That general value comparison
>
> B  ancestor::* = $ancestor-with-id
>
> looks odd, shouldn't that be
>
> B  ancestor::*[. is $ancestor-with-id]
>
> ? I would expect node identity comparison and not value comparison.
>
> Whether that improves performance and then also on two different
> implementations is something I can't tell without testing.
>
>
>
> > 2. Is there an alternative way of generating ids (possibly having less
> > human-readable values) that would work in both the xquery and xslt 
> > realm?
>
> It looks like a job for XSLT's xsl:number and I wonder whether your
> database xquery processor doesn't provide a way to simply run an XSLT
> transformation.

--
Pieter Lamers
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