Code examples for article http://developer.marklogic.com/blog/learning-with-query-trace

ex01.xqy

//group[@type eq 'widget']

ex02.xqy

for $n in (1 to 300) return
xdmp:document-insert(concat("/group",$n,".xml"),
  document {
    let $pos := ($n mod 3) + 1
    let $type := ("widget","person","place")[$pos] return
    <group type="{$type}">stuff</group>
  }
)

ex03.xqy

xdmp:query-trace(true()),
//group[@type eq 'widget']

ex04.txt

Analyzing path: fn:collection()/descendant::group[@type eq "widget"]
Step 1 is searchable: fn:collection()
Step 2 is searchable: descendant::group[@type eq "widget"]
Path is fully searchable.
Gathering constraints.
Comparison contributed hash value constraint: group/@type = "widget"
Step 2 predicate 1 contributed 1 constraint: @type eq "widget"
Comparison contributed hash value constraint: group/@type = "widget"
Step 2 predicate 1 contributed 1 constraint: @type eq "widget"
Step 2 contributed 2 constraints: descendant::group[@type eq "widget"]
Executing search.
Selected 100 fragments to filter

ex05.xqy

for $n in (1 to 300) return
xdmp:document-insert(concat("/logfile",$n,".xml"),
  document {
    let $pos := ($n mod 3) + 1
    let $host := concat("host",$pos) return
    <logfile host="{$host}"/>
  }
)

ex06.xqy

xdmp:query-trace(true()),
//logfile[@host eq 'host1']

ex07.txt

Selected 100 fragments to filter