DB2 FOR LUW / DB2FORLUW / A50 - DB2

Excessive application heap memory usage may be seen on systems 
with query parallelism enabled (INTRA_PARALLEL = YES or other 
methods).  This is due to an accounting logic error when 
tracking memory usage for the REBAL operator, which rebalances 
work between subagents working for the query. 
 
This is not a memory leak, as the memory will be freed at the 
end of query execution.  Some systems may experience severe 
symptoms such as paging and/or memory exhaustion. 
 
Application Heap memory usage can be monitored using the 
MON_GET_MEMORY_POOL routine or db2pd -alldbs -mempools.  If very 
high usage levels are seen which deplete available system or 
instance memory, the problem can be confirmed checking for high 
allocations from file source of 1984253944. 
 
db2pd -alldbs -memblocks appl 1 sort 
 
Memory blocks sorted by size for apph pool: 
PoolID     PoolName   TotalSize(Bytes)     TotalCount LOC   File 
1          apph       69551569             87865      1057 
1984253944 
...

**************************************************************** 
* USERS AFFECTED:                                              * 
* Systems using query parallelism (typically with              * 
* intra_parallel set to YES)                                   * 
**************************************************************** 
* PROBLEM DESCRIPTION:                                         * 
* See Error Description                                        * 
**************************************************************** 
* RECOMMENDATION:                                              * 
* Upgrade to DB2 Version 10.5 Fix pack 5                       * 
****************************************************************

An internal registry variable can be used to disable the REBAL 
OPERATOR 
   db2set DB2_COMPILER_SMP_OVERRIDES=1 
This setting requires recycling the db2 instance 
(db2stop/db2start).  The setting should be removed 
   db2set DB2_COMPILER_SMP_OVERRIDES= 
after upgrading to a level containing the APAR fix

Problem first fixed in DB2 Version 10.5 Fix pack 5

see Local Fix

Date  - problem reported    :
Date  - problem closed      :
Date  - last modified       :

15.07.2014
19.01.2016
19.01.2016