DB2 FOR LUW / DB2FORLUW / A10 - DB2

In a partitioned database environment, the DB2 optimizer can 
consider a group by (GB) alternative where the GB is partially 
performed on each database partition, accumulating partial 
results which are then re-distributed based on the grouping key 
to complete the GB. For example, if a table T is hash 
distributed across multiple database partitions based on column 
X, then for the query 
 
select a,max(b),min(c),sum(d) 
from T 
group by a 
 
the GB cannot be completed locally at each partition since the 
grouping key does not contain the hash distribution key.  As a 
result, a partial grouping result will be computed locally at 
each database partition, with the partial aggregation results 
and their source columns flowing through a table queue (TQ). 
 
If these source columns are not required beyond the partial 
result, width of the stream can be wider than is necessary which 
can significantly degrade query execution performance.

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* USERS AFFECTED:                                              * 
* The problem only occurs in a database partitioned            * 
* environment.                                                 * 
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* PROBLEM DESCRIPTION:                                         * 
* See Error Description                                        * 
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* RECOMMENDATION:                                              * 
* Upgrade to DB2 version 10.1 Fix Pack 2.                      * 
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DB2 Version 10.1 Fix Pack 2 for Linux, UNIX, and Windows
 DB2 Version 10.1 Fix Pack 3 for Linux, UNIX, and Windows
 DB2 Version 10.1 Fix Pack 4 for Linux, UNIX, and Windows
 DB2 Version 10.1 Fix Pack 3a for Linux, UNIX, and Windows
 DB2 Version 10.1 Fix Pack 6 for Linux, UNIX, and Windows
 

The problem is first fixed in DB2 version 10.1 Fix Pack 2

keiner bekannt / siehe Local-Fix

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

23.10.2012
15.04.2013
15.04.2013