Very similar FLWOR queries with very dissimilar performances

Question

Hello,
I have two queries which seem to me to be equivalent but have very different performances (<1s vs >30s)
Sample xml data
<MARQUE>
<CodeApp>080000000</CodeApp>
</Wares>blah blah blah</Wares>
</MARQUE>
Query #1, with acceptable performances
query 'for $m in collection("canada/db") where $m/MARQUE/CodeApp >= "080000000" and $m/MARQUE/CodeApp <= "0801000000"
return $m/MARQUE/Wares'
Query #2, with bad performances
query 'for $m in collection("canada/db") where $m/MARQUE/CodeApp >= "080000000" and $m/MARQUE/CodeApp <= "0801000000"
return <wares>{$m/MARQUE/Wares}</wares>'
I would expect the second query to be simply adding formatting around the results, but it takes on a very different approach in the query plan. Basicaly, when I "setVerbose 2 2" I see two lines of debugging for the first one:
Query - canada/db - R(CodeApp,>=,'080000000',<=,'0801000000') : [1002] 538279 ...
Query - canada/db - n(R(CodeApp,>=,'080000000',<=,'0801000000'),P(Wares)) : [1002] 538279...
But the second query gives me 1000 of these:
Query - canada/db - P(Wares) : [786982] 2 3 4 5 6 7 8 9 10 11 ...
It seems the first query is fetching all of the document and then giving me what I want and the second one is getting the ids of the documents and then asking for the wares of each of the 1000 documents returned.
Anyone knows how I can reformulate my second query to make it faster?
Alex
ps:
indices:
Index: node-element-presence-none node-element-equality-string for node {}:CodeApp
Index: edge-element-equality-string node-element-presence-none for node {}:Wares
query plans:
plan for #1
<XQuery>
<Navigation>
<QueryPlanFunction result="collection" container="canada/db">
<OQPlan>n(R(node-element-equality-string,CodeApp,>=,'080000000',<=,'080100000'),P(edge-element-equality-string,prefix,MARQUE.Wares))</OQPlan>
</QueryPlanFunction>
<DbXmlFilter>
<Navigation>
<Step axis="child" name="MARQUE" nodeType="element"/>
<Step axis="child" name="CodeApp" nodeType="element"/>
<DbXmlCompare name="greater_than_equal">
<Sequence>
<AnyAtomicTypeConstructor value="080000000" typeuri="http://www.w3.org/2001/XMLSchema" typename="string"/>
</Sequence>
</DbXmlCompare>
</Navigation>
</DbXmlFilter>
<DbXmlFilter>
<Navigation>
<Step axis="child" name="MARQUE" nodeType="element"/>
<Step axis="child" name="CodeApp" nodeType="element"/>
<DbXmlCompare name="less_than_equal">
<Sequence>
<AnyAtomicTypeConstructor value="080100000" typeuri="http://www.w3.org/2001/XMLSchema" typename="string"/>
</Sequence>
</DbXmlCompare>
</Navigation>
</DbXmlFilter>
<Step axis="child" name="MARQUE" nodeType="element"/>
<Step axis="child" name="Wares" nodeType="element"/>
</Navigation>
</XQuery>
plan #2
<XQuery>
<FLWOR>
<ForBinding name="m">
<Navigation>
<QueryPlanFunction result="collection" container="canada/db">
<OQPlan>R(node-element-equality-string,CodeApp,>=,'080000000',<=,'080100000')</OQPlan>
</QueryPlanFunction>
<DbXmlFilter>
<Navigation>
<Step axis="child" name="MARQUE" nodeType="element"/>
<Step axis="child" name="CodeApp" nodeType="element"/>
<DbXmlCompare name="greater_than_equal">
<Sequence>
<AnyAtomicTypeConstructor value="080000000" typeuri="http://www.w3.org/2001/XMLSchema" typename="string"/>
</Sequence>
</DbXmlCompare>
</Navigation>
</DbXmlFilter>
<DbXmlFilter>
<Navigation>
<Step axis="child" name="MARQUE" nodeType="element"/>
<Step axis="child" name="CodeApp" nodeType="element"/>
<DbXmlCompare name="less_than_equal">
<Sequence>
<AnyAtomicTypeConstructor value="080100000" typeuri="http://www.w3.org/2001/XMLSchema" typename="string"/>
</Sequence>
</DbXmlCompare>
</Navigation>
</DbXmlFilter>
</Navigation>
</ForBinding>
<DOMConstructor type="element">
<Name>
<Sequence>
<AnyAtomicTypeConstructor value="wares" typeuri="http://www.w3.org/2001/XMLSchema" typename="string"/>
</Sequence>
</Name>
<Children>
<Navigation>
<Variable name="m"/>
<Step axis="child" name="MARQUE" nodeType="element"/>
<Step axis="child" name="Wares" nodeType="element">
<OQPlan>P(edge-element-equality-string,prefix,MARQUE.Wares)</OQPlan>
</Step>
</Navigation>
</Children>
</DOMConstructor>
</FLWOR>
</XQuery>

Answer 1

Hi John, thank you for your answer.
Unfortunately, I am positive about my times. Both my queries were eager (setLazy off). I tried outputing the 1000 hits to the screen with the sub-second query and it added roughly the time to display it on the console that is approximately 3 seconds. We are still very far off from the more than 30 seconds it takes to run the second query (without printing even! add another 3 seconds to print that one too).
Although you say that the logging is misleading, the differences in the query plan are a hint to me that something is a miss in my second query. The first queryplan uses both indexes
<OQPlan>n(R(node-element-equality-string,CodeApp,>=,'080000000',<=,'080100000'),P(edge-element-equality-string,prefix,MARQUE.Wares))</OQPlan>
in the early Navigation part of the query plan, where the other one seems to use just the CodeApp part in the Navigation and the Wares part only at the DOMConstructor phase...
Alex