Hi, All
I want to get a unique id at ML, a xml called ids.xml will store my id just
like below:
<id>100</id>
Here is my xquery function, it will update ids.xml file after calling it.
define function nextSomeID($number as xs:integer) as xs:integer
{
let $id := doc("ids.xml")/id/text()
let $nextId := xs:integer($id) + 1
let $update := xdmp:node-replace($id, text{$nextId + $number - 1})
return $nextId
}
the java client method (synchronized also) will call this function to get
next id, but in fact, I still get duplicated id some times.
Notice:
1) I using multi-thread to call this java method.
2) para $number can be 1,2,3,4...., for example, if $number is 3 and current
id=2, nextSomeID will return 3, id will be 2+3=5
So, what situation will happen this? Very confused.
The only possible way is $id get the duplicated value at here:
let $id := doc("ids.xml")/id/text()
But seems before return $nextId, ids.xml has been updated. so,
doc("ids.xml")/id/text() will always get latest values, right?
Very confused about that, can anyone explain that?
--
Rgds!
Tide Kong
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