Hi Christian,

Thanks for the explanation. So functions never use indices are the moment?

/Andy

On Sat, Dec 10, 2011 at 11:02 PM, Christian Grün christian.gruen@gmail.comwrote:

Hi Andy,

yes, it should give the same error. I only have tried the latest 7.1 snapshot, which returns errors for both of the queries. The performance may be suboptimal here, as the equality predicate in the function cannot be optimized for index access (this is because the incoming nodes may relate to a database instance that has no attribute index). This may be changed in future by choosing the best evaluation plan at runtime.

Hope this helps, Christian

On Sat, Dec 10, 2011 at 11:55 PM, Andy Bunce bunce.andy@gmail.com wrote:

...

Hi with the factbook.xml database open in the 7.0.2 gui

declare function local:linkto($id as xs:string){ let $d:=//city let $a:=$d[@id=$id] return $a }; local:linkto("f0_1461")

Gives the "no context item for root" error on the //city line, but

declare function local:linkto($id as xs:string){ let $a:=//city[@id=$id] return $a }; local:linkto("f0_1461")

Works fine. Should it give the same error? If it should, and I try to pass the nodes into the function then the relative performance is not good at all. declare function local:linkto2($id as xs:string,$nodes as node()*){ let $c:=$nodes[@id=$id] let $n:=name($c[1]) return <a href="/fb/{$n}/{$id}"> {$c/name/string()}

</a> };

let $caps:=//country/@capital/string() for $id in $caps return local:linkto2($id,//city)

/Andy