Hi Günter,
I had one more look at the slow query you were encountering:
for $city in doc('factbook')//city/name for $hits in ft:mark($city[.//text() contains text {$query} using wildcards]) let $country_of_city := $city/ancestor::country/name return (: slow version: Evaluating 35.78 :) (: <hit><city>{$hits}</city><country>{$country_of_city}</country></hit> :)
This one was more tricky than I expected, because the ft:mark function can produce multiple results for a single node. This is why the sliding of the let clause, which slows down your query, can be beneficial in other cases. The following query will generate 20 results (10 "mark" elements, 10 text nodes), so it will be evaluated faster if the let clause is slided over the for clause:
let $input := (<X>{ 'A.A.A.A.A.A.A.A.A.A.' }</X> update () )/text() for $hits in ft:mark($input[. contains text 'A']) let $parent := $input/.. return <hit id='{ db:node-id($parent) }'>{ $hits }</hit>
Well, those are lots of internal details that I think you can easily ignore. In a nutshell: Just use 'let' and 'where' instead tof 'for':
let $input := (<X>{ 'A.A.A.A.A.A.A.A.A.A.' }</X> update () )/text() let $hits := ft:mark($input[. contains text 'A']) where $hits let $parent := $input/.. return <hit id='{ db:node-id($parent) }'>{ $hits }</hit>
Christian