DB2 FOR LUW / DB2FORLUW / 970 - DB2

Select queries which use external scalar UDF in conjunction with 
the ORDER BY clause do not parallelize well in DPF and lead to 
bad performance. 
To benefit from the optimization the following conditions must 
be satisfied: 
1. The environment must be DPF. 
2. There must be a order by clause declared on the outer most 
select. 
3. The select must have a reference to an external scalar UDF. 
4. The UDF must not be non-deterministic, perform external 
action or have a scratchpad. 
 
eg. 
select CD_DEMO_SK, PROMO(CD_DEP_COUNT,CD_PURCHASE_ESTIMATE) as 
UDF 
from T1 
ORDER BY CD_DEMO_SK; 
 
In the SQL example above "CD_DEMO_SK" is Primary Key and PROMO 
is an external UDF.

rewrite the above query as: 
select temp.CD_DEMO_SK, temp.UDF FROM ( 
      select CD_DEMO_SK, 
PROMO(CD_DEP_COUNT,CD_PURCHASE_ESTIMATE) as UDF from T1) as temp 
ORDER BY temp.CD_DEMO_SK;

DB2 Version 9.7 Fix Pack 3 for Linux, UNIX, and Windows
 DB2 Version 9.7 Fix Pack 3a for Linux, UNIX, and Windows
 DB2 Version 9.7 Fix Pack 4 for Linux, UNIX, and Windows
 DB2 Version 9.7 Fix Pack 5 for Linux, UNIX, and Windows
 DB2 Version 9.7 Fix Pack 6 for Linux, UNIX, and Windows
 DB2 Version 9.7 Fix Pack 7 for Linux, UNIX, and Windows
 DB2 Version 9.7 Fix Pack 8 for Linux, UNIX, and Windows
 DB2 Version 9.7 Fix Pack 9 for Linux, UNIX, and Windows
 DB2 Version 9.7 Fix Pack 9a for Linux, UNIX, and Windows
 DB2 Version 9.7 Fix Pack 10 for Linux, UNIX, and Windows
 

keiner bekannt / siehe Local-Fix

N/A

Datum - Problem gemeldet    :
Datum - Problem geschlossen :
Datum - der letzten Änderung:

30.06.2010
23.09.2010
23.09.2010