Hello, This is common problem in XQuery. There hardly is a way of optimizing it without introducing special "group by" operator to FLWOR. We are currently working on it.
What version of Sedna do you use? Development branch contains optimized "distinct-values" function, so it may be faster. Ilya Taranov, Sedna Team. On Mon, Mar 14, 2011 at 3:04 PM, giocondo sticca <[email protected]> wrote: > Hi, > > I have performance problem with this query: > > declare namespace s="http://www.schemata.it/lml/1.0";; > declare namespace l="http://www.schemata.it/lml/1.0/linker";; > > let $tmp := for $b in ftindex-scan("ft_body","art. > 15","nosort")/../s:meta/s:classification/s:index > > return $b > > return > > <result> > {for $i in distinct-values($tmp) > return > <section><name>{$i}</name><total>{count($tmp[.=$i])}</total></section> > } > </result> > > Total time: 56500ms > > I have also tried this variant, but total time is always too high > > declare namespace s="http://www.schemata.it/lml/1.0";; > declare namespace l="http://www.schemata.it/lml/1.0/linker";; > > let $tmp := for $b in ftindex-scan("ft_body","art. > 15","nosort")/../s:meta/s:classification/s:index > > return $b > > return > > <result> > {for $sec in distinct-values($tmp) > return <section><name>{$sec}</name><total>{count($tmp intersect > index-scan("test",$sec,"EQ"))}</total></section> > } > </result> > > Total time: 20453ms > > Any suggestion ? > > Thanks. > > P.S. > > This is the profile of the second query: > > <profile xmlns="http://www.modis.ispras.ru/sedna";> > <total-time>23.970</total-time> > </profile><prolog xmlns="http://www.modis.ispras.ru/sedna";> > <namespace prefix="l" uri="http://www.schemata.it/lml/1.0/linker"/> > <namespace prefix="s" uri="http://www.schemata.it/lml/1.0"/> > </prolog><query xmlns="http://www.modis.ispras.ru/sedna";> > <operation xmlns="" name="PPQueryRoot" time="23.970" calls="1"> > <operation name="PPLet" position="4:5" time="23.968" calls="2"> > <produces> > <variable descriptor="1" name="tmp"/> > </produces> > <operation name="PPReturn" position="4:17" time="2.272" calls="22341"> > <produces> > <variable descriptor="0" name="b"/> > </produces> > <operation name="PPDDO" position="4:93" time="2.255" calls="22341"> > <operation name="PPAxisChild" step="child::element(s:index)" > position="4:93" time="2.109" calls="22341"> > <operation name="PPAxisChild" > step="child::element(s:classification)" position="4:76" time="1.986" > calls="22341"> > <operation name="PPAxisChild" step="child::element(s:meta)" > position="4:69" time="1.820" calls="22341"> > <operation name="PPAxisParent" step="parent::node()" > position="4:66" time="1.634" calls="22341"> > <operation name="PPSeqChecker" mode="node" position="4:66" > time="1.460" calls="22341"> > <operation name="PPFtIndexScan" position="4:23" > time="1.456" calls="22341"> > <operation name="PPConst" type="xs:string" > value="ft_body" position="4:36" time="0.000" calls="2"/> > <operation name="PPConst" type="xs:string" value="art. > 15" position="4:46" time="0.000" calls="2"/> > <operation name="PPConst" type="xs:string" > value="nosort" position="4:56" time="0.000" calls="2"/> > </operation> > </operation> > </operation> > </operation> > </operation> > </operation> > </operation> > <operation name="PPVariable" descriptor="0" variable-name="b" > position="6:8" time="0.004" calls="44680"/> > </operation> > <operation name="PPElementConstructor" element-name="result" > deep-copy="true" namespace-inside="false" position="10:1" time="23.968" > calls="2"> > <operation name="PPSequence" position="10:1" time="23.962" > calls="467"> > <operation name="PPSpaceSequence" doc-order="false" > position="11:1" time="23.962" calls="467"> > <operation name="PPReturn" position="11:6" time="23.962" > calls="467"> > <produces> > <variable descriptor="2" name="sec"/> > </produces> > <operation name="PPFnDistinctValues" position="11:14" > time="3.207" calls="467"> > <operation name="PPVariable" descriptor="1" > variable-name="tmp" position="11:30" time="2.282" calls="22341"/> > </operation> > <operation name="PPElementConstructor" element-name="section" > deep-copy="false" namespace-inside="false" position="12:8" time="20.755" > calls="932"> > <operation name="PPSequence" position="12:8" time="20.752" > calls="1398"> > <operation name="PPElementConstructor" element-name="name" > deep-copy="false" namespace-inside="false" position="12:17" time="0.006" > calls="932"> > <operation name="PPSequence" position="12:17" > time="0.001" calls="932"> > <operation name="PPSpaceSequence" doc-order="false" > position="12:23" time="0.001" calls="932"> > <operation name="PPVariable" descriptor="2" > variable-name="sec" position="12:24" time="0.001" calls="932"/> > </operation> > </operation> > </operation> > <operation name="PPElementConstructor" > element-name="total" deep-copy="false" namespace-inside="false" > position="12:36" time="20.745" calls="932"> > <operation name="PPSequence" position="12:36" > time="20.737" calls="932"> > <operation name="PPSpaceSequence" doc-order="false" > position="12:43" time="20.736" calls="932"> > <operation name="PPFnCount" position="12:44" > time="20.736" calls="932"> > <operation name="PPIntersect" doc-order="false" > position="12:50" time="20.731" calls="22806"> > <operation name="PPSXptr" position="12:50" > time="17.913" calls="10342429"> > <operation name="PPVariable" descriptor="1" > variable-name="tmp" position="12:50" time="2.116" calls="10410906"/> > </operation> > <operation name="PPSXptr" position="12:65" > time="1.511" calls="487246"> > <operation name="PPIndexScan" > index-scan-condition="EQ" position="12:65" time="0.222" calls="487266"> > <operation name="PPConst" type="xs:string" > value="test" position="12:76" time="0.000" calls="932"/> > <operation name="PPVariable" descriptor="2" > variable-name="sec" position="12:83" time="0.000" calls="932"/> > <operation name="PPConst" type="xs:integer" > value="0" position="12:65" time="0.000" calls="0"/> > </operation> > </operation> > </operation> > </operation> > </operation> > </operation> > </operation> > </operation> > </operation> > </operation> > </operation> > </operation> > </operation> > </operation> > </operation> > </query> > > All the tests was performed on a DELL PowerEdge 2009 (Quad-Core XEON > E5410, 4GB RAM, 3 x 750GB Raid SAS) with Debian Lenny (Kernel version > 2.6.26-2-amd64) and Sedna 3.4.228 > > ------------------------------------------------------------------------------ > Colocation vs. Managed Hosting > A question and answer guide to determining the best fit > for your organization - today and in the future. > http://p.sf.net/sfu/internap-sfd2d > _______________________________________________ > Sedna-discussion mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/sedna-discussion > > -- Thanks in advance, Ilya Taranov. ------------------------------------------------------------------------------ Colocation vs. Managed Hosting A question and answer guide to determining the best fit for your organization - today and in the future. http://p.sf.net/sfu/internap-sfd2d _______________________________________________ Sedna-discussion mailing list [email protected] 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