DB2 - Problembeschreibung
Problem IT02244 | Status: Geschlossen |
DIRTY LIST LATCH CONTENTION DROPPING TEMP TABLES AT COMMIT CREATED BY XML PROCESSING | |
Produkt: | |
DB2 FOR LUW / DB2FORLUW / A10 - DB2 | |
Problembeschreibung: | |
When a transaction performs XML processing involving the XMLTable function, a temp table may need to be created. e.g. a select like : select X.COL1 from XMLSOURCE S, XMLTABLE ( '$s/NOD1' PASSING S.MYXML as "s" COLUMNS COL1 VARCHAR(100) PATH 'TAB1/COL1' ) AS X; would create a system temporary table. When the transaction is completed , commit or rollback, this temp table is dropped. Dropping of these temps is usually executed asynchronously by the prefetcher edus to minimize the performance impact. However, when there is a high level of concurrency it is possible that the available prefetch requests become exhausted at which point the agent performing the commit/rollback will drop the temp. This in turn can increase the concurrency on the function performing the actual drop and this can create a situation of high latch contention driving significant performance impact. The stacks for the sessions in contention may show : sqloSpinLockConflict sqlbGetDLSize sqlbPurgeObject sqlbSMSDeleteObject sqldDropObj sqldDropTable sqldTableDrop and/or sqloSpinLockConflict sqlbSplatObject sqlbPurgeObject sqlbSMSDeleteObject sqldDropObj sqldDropTable sqldTableDrop | |
Problem-Zusammenfassung: | |
See Problem Description | |
Local-Fix: | |
The problem can be alleviated by 1. increasing the available prefetch requests by setting values for NUMPREFETCHQUEUES and PREFETCHQUEUESIZE. ( in releases < V10.1 ). See Infocenter on how to set these. 2. associating a smaller dedicated bufferpool to the temp tablespace. bufferpool to temp tablespaces. | |
Lösung | |
See Problem Description | |
Workaround | |
See Problem Description | |
Weitere Daten | |
Datum - Problem gemeldet : Datum - Problem geschlossen : Datum - der letzten Änderung: | 05.06.2014 15.07.2015 15.07.2015 |
Problem behoben ab folgender Versionen (IBM BugInfos) | |
Problem behoben lt. FixList in der Version | |
10.1.0.5 |