Hi,
I am trying to write a xquery-expression that does a test on an
attribute (id="1"). Unfortunately the query execution time for this
query is really bad (>30 seconds).
Is there any way to find out why this query takes so long? 30 seconds
for a test on one
single attribute is just way to high for our use-case. I read that
MonetDB automatically creates indices on all attribute - is there a way
to test, if there was an index created for that attribute and if that
index was used for query execution?
The query (in File q3.xp) is supposed to return the molecule with id "1"
declare namespace xq=
"http://www.xml-cml.org/schema";
<smiles> {
for $i in collection("tu")
where $i/xq:molecule/@id = "1"
return
<smile>{$i}</smile>
} </smiles>
The query is executed like this:
# mclient -t -lx -G q3.xp
...
Trans 55.684 msec
Shred 18.818 msec
Query 29335.766 msec
Print 0.258 msec
The database contains 1.000.000 XML-documents in a single collection,
is updatable and is about 2601 MiB. A document looks similar to this
one:
<?xml
version="1.0" encoding="UTF-8"?>
<molecule id=“1“ xmlns=
"http://www.xml-cml.org/schema">
<bondArray atomRef1="..." order="..."/>
<atomArray atomID="..." elementType="..." x3="..."/>
<identifier convention="iupac:smile" value="..."/>
<identifier convention="iupac:inchi" value="..."/>
</molecule>
We are using:
"MonetDB/XQuery 0.36.5, based on the
pathfinder compiler
and
MonetDB 4.36.1"
Thank you very much for any help!
Patrick