DB2 - Problembeschreibung
Problem IC80537 | Status: Geschlossen |
XQUERY WHICH CONTAINS XPATH EXTRACTION IN A FOR ... LET STATEMENT HAS A BAD PERFORMANCE | |
Produkt: | |
DB2 FOR LUW / DB2FORLUW / 970 - DB2 | |
Problembeschreibung: | |
The performance of an XQUERY which contains path extraction in a 'for loop' statement, such as 'for ... let' and 'for ...', has a bad performance in V97 compared to V91. While the performance is bad in general, some queries may show worse performance than the others, depending on the amount of data to be extracted. The problem is caused by a bad plan being chosen by the optimizer. An example of such query is: ----- xquery declare namespace xxxx="http://xxxx"; let $base := db2-fn:xmlcolumn("xxxx")/ap:LimitData for $name in fn:distinct-values( $base[./xxxx:ScheduleDate < xs:string(fn:current-date())]/xxxx:ChargeList/xxxx:Charge/xxxx:U serSectionName ), $count in fn:count( $base[./xxxx:ScheduleDate < xs:string(fn:current-date()) and ./xxxx:ChargeList/xxxx:Charge/xxxx:UserSectionName=$name] ) order by $name return <xxxx:LDOutline> <xxxx:Name>{ $name }</xxxx:Name> <xxxx:Count>{ $count } </xxxx:Count> </xxxx:LDOutline>@ ----- Another example of such query is : ----- xquery declare namespace xxxx="http://xxxx"; let $base := db2-fn:xmlcolumn("xxxx")/xxxx:LimitData for $name in fn:distinct-values( $base[./xxxx:ScheduleDate < xs:string(fn:current-date())]/xxxx:ChargeList/xxxx:Charge/xxxx:U serSectionName ) order by $name return <xxxx:LDOutline> <xxxx:Name>{ $name } </xxxx:Name> <xxxx:Count> { fn:count( $base[./xxxx:ScheduleDate < xs:string(fn:current-date()) and ./xxxx:ChargeList/xxxx: Charge/xxxx:UserSectionName=$name] ) } </xxxx:Count> </xxxx:LDOutline> ; ----- | |
Problem-Zusammenfassung: | |
**************************************************************** * USERS AFFECTED: * * DB2 UDB Version 9.7. * **************************************************************** * PROBLEM DESCRIPTION: * * See Error description field for more information. * **************************************************************** * RECOMMENDATION: * * Upgrade to Version 9.7 FixPack 6. * **************************************************************** | |
Local-Fix: | |
verfügbare FixPacks: | |
DB2 Version 9.7 Fix Pack 7 for Linux, UNIX, and Windows | |
Lösung | |
Problem was first fixed in DB2 UDB Version 9.7 FixPack 6. Upgrade to Version 9.7 FixPack 6. | |
Workaround | |
keiner bekannt / siehe Local-Fix | |
Bug-Verfolgung | |
Vorgänger : APAR is sysrouted TO one or more of the following: IC80587 Nachfolger : | |
Weitere Daten | |
Datum - Problem gemeldet : Datum - Problem geschlossen : Datum - der letzten Änderung: | 21.12.2011 20.10.2012 20.10.2012 |
Problem behoben ab folgender Versionen (IBM BugInfos) | |
9.7.FP6 | |
Problem behoben lt. FixList in der Version | |
9.7.0.7 |