DB2 - Problembeschreibung
| Problem IC63995 | Status: Geschlossen |
VERY SLOW QUERY DUE TO CORRELATED HSJN ON THE INNER OF NLJN | |
| Produkt: | |
DB2 FOR LUW / DB2FORLUW / 970 - DB2 | |
| Problembeschreibung: | |
Query runs very slow due to a correlated HSJN on the inner of
a NLJN.
Example :
0.306141
NLJOIN
( 16)
1.03309e+07
199966
/--------------+----------\
5.9579e+07 5.1384e-09
IXSCAN HSJOIN
( 17) ( 18)
310054 78.8668
199957 9.04414
| /---------+----------\
5.9579e+07 1
INDEX: GRPBY
<schema.inx1> ( 27)
Q7 35.0439
4.02207
|
2.55873
FETCH
( 28)
35.0435
4.02207
/---+---\
2.55873 1.52447e+08
IXSCAN TABLE:
( 29) <schema.tab1>
26.1437 Q9
3
|
1.52447e+08
INDEX:
<schema.inx2>
Q9
Example of optimized part of SQL :
(SELECT MIN(Q10.$C0)
FROM
(SELECT Q9.<col1>
FROM <schema.tab1> AS Q9
WHERE (Q9.<col2> = Q7.<col2>)) AS Q10) AS Q11,
This is a side effect of another code fix which went in V9.1
FP5 | |
| Problem-Zusammenfassung: | |
Users Affected : Any user using V9.1 FP5 and above Problem Summay : Please see the APAR description Problem Solution : This is an under-estimation of the buffer requirement which is fixed by this APAR | |
| Local-Fix: | |
Use optimizer guideline similar to : <OPTGUIDELINES><NLJOIN><ACCESS TABID='Q7'/><ACCESS TABID='Q11'/></NLJOIN></OPTGUIDELINES> | |
| verfügbare FixPacks: | |
DB2 Version 9.7 Fix Pack 1 for Linux, UNIX, and Windows | |
| Lösung | |
This APAR is fixed in V9.7 FixPak1 (CQ defect#wsdbu00548004) | |
| Workaround | |
keiner bekannt / siehe Local-Fix | |
| Weitere Daten | |
Datum - Problem gemeldet : Datum - Problem geschlossen : Datum - der letzten Änderung: | 22.10.2009 30.12.2009 30.12.2009 |
| Problem behoben ab folgender Versionen (IBM BugInfos) | |
9.7. | |
| Problem behoben lt. FixList in der Version | |
| 9.7.0.1 |
|