DB2 FOR LUW / DB2FORLUW / 950 - DB2

A logic error in STMM's tracking of throttled sort requests 
results in a continuous upward trend in the enforced minimum 
size for shared sort (SHEAPTHRES_SHR).  This may cause other 
STMM-tuned areas to be forced down, potentially causing 
performance degradation or other resource issues (SQL1218). 
 
This problem exists in: 
Version 9.1 Fix Pack 6 and higher 
Version 9.5 Fix Pack 2 and higher 
Version 9.7 GA and higher 
 
The following entry can be seen in STMM logs each time a 
permanent increase is introduced (at DIAGLEVEL 3 or above) 
 
FUNCTION: DB2 UDB, Self tuning memory manager, 
stmmRegisterReserveSharedSortSpace, probe:3038 
MESSAGE : Unexpected value in accounting of reserved sort memory 
-  91545 -  1 
          -  5409 -  10641 -  0 
 
Occasionally STMM may detect that the minimum size has grown 
beyond a reasonable range, and may cap the minimum size, as 
evidenced by the following STMM log entry (logged regardless of 
DIAGLEVEL): 
 
FUNCTION: DB2 UDB, Self tuning memory manager, 
stmmComputeMinSHEAPTHRES, probe:837 
MESSAGE : Unexpected minimum value for SHEAPTHRES_SHR - value 
automatically 
          corrected -  299025 -  2076 -  342641 -  249120 -  96 
-  0 - 
          96.000000 -  1 -  31 -  274113 -  735 
 
The values are only maintained while the database is active, so 
recycling the database will reset the minimum size to normal 
values.  Alternatively, use a fixed setting for SHEAPTHRES_SHR

**************************************************************** 
* USERS AFFECTED:                                              * 
* Systems where STMM is tuning Sort memory                     * 
**************************************************************** 
* PROBLEM DESCRIPTION:                                         * 
* See Error Description                                        * 
**************************************************************** 
* RECOMMENDATION:                                              * 
* Upgrade to DB2 Version 9.5 Fix Pack 10                       * 
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Problem first fixed in DB2 Version 9.5 Fix pack 10

not known / see Local fix

forerunner  : APAR is sysrouted TO one or more of the following: IC82182 
follow-up : 

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

20.03.2012
30.10.2012
30.10.2012

9.5.FP10