[Exist-development] How to effectively count instances?

[Adam H. <Ada...@be...>]

Hi
I have a (rather big  - several hundred MB) XML of the following
structure stored in the db:
<krm:catalogue>
<krm:j id="1637192" pID="1637191" teryt="3716704" powiat="2183789"
wojewodztwo="2183783"
        kategoria="1">
        <krm:k id="1637194">
            <krm:spec id="2205172"/>
            <krm:spec id="2205241"/>
            <krm:rk id="2205699"/>
            <krm:rk id="2205588"/>
            <krm:rk id="2205589"/>
            <krm:rk id="2205358"/>
            <krm:dsc id="2205171"/>
            <krm:dsc id="2205239"/>
        </krm:k>
        <krm:k id="1637193">
            <krm:spec id="2205213"/>
            <krm:rc id="2206812"/>
            <krm:rk id="2205564"/>
            <krm:dsc id="2205211"/>
            <krm:sc id="2206811"/>
            <krm:sc id="2206808"/>
            <krm:sc id="2206804"/>
            <krm:sc id="2206807"/>
            <krm:sc id="2206806"/>
            <krm:sc id="2206805"/>
            <krm:sc id="2206810"/>
            <krm:sc id="2206795"/>
            <krm:sc id="2206798"/>
            <krm:sc id="2206794"/>
            <krm:sc id="2206791"/>
            <krm:sc id="2206793"/>
            <krm:sc id="2206799"/>
            <krm:sc id="2206797"/>
            <krm:sc id="2206802"/>
            <krm:sc id="2206801"/>
            <krm:sc id="2206800"/>
            <krm:sc id="2206792"/>
            <krm:sc id="2206796"/>
            <krm:sc id="2206809"/>
        </krm:k>
</krm:j>
</krm:catalogue>

where there are many nodes of type krm:j, which have many nodes of
type krm:k. In a rather elaborate process, I filter those nodes, and
receive a certain subtree - which, therefore, still has the same
organization. And now I need to count  occurrances of every @id in
every given node type (ie. I need to retrieve information that node
krm:sc with id 2206800 occurs 5 times, and krm:sc with id 2206801
occurs 20 times). I found out that just performing a count() on a
nodeset i(XPath expression result) s surprisingly slow, and can take
my xquery from below 30 seconds to well over 10 minutes. I have
indices set up, which sped things up a lot in other contexts, but
still - counting occurences is a big pain in the lower back. I wonder
- is there any clever exist-only function which could help mi retrieve
the counts?

-- 
Best regards
Adam Hepner

tel. 509 093 095
e-mail: ada...@be...
http://AdamHepner.pl