DB2 FOR LUW / DB2FORLUW / 950 - DB2

This APAR applies to STMM configurations where DATABASE_MEMORY 
is a fixed value or AUTOMATIC. 
 
If there is a tuning increase failure, STMM may incorrectly try 
to compensate for the failure by repeatedly trying to include 
the amount of the failure in future tuning increases.  These 
future increases may be over-aggressive and be aborted to avoid 
overcommiting memory on a system, resulting in further tuning 
increase failures. 
The failures themselves have no impact on the system, the check 
occurs before any configuration change is attempted. 
The impact can be that STMM stops performing more reasonable 
tuning increases, i.e. optimal performance may not be obtained. 
 
The first event seen is an initial tuning increase failure, 
which can be normal, and is logged to both the STMM log and the 
db2diag.log: 
 
FUNCTION: DB2 UDB, Self tuning memory manager, 
stmmCheckIfFreeMemoryIsEnoughForSizeIncr, probe:667 
MESSAGE : ZRC=0xFFFFEC49=-5047 
DATA #1 : String, 146 bytes 
There is not enough free memory for size increase. 
 
Secondly, the STMM logs will show a non-0 value for lost4KPages: 
Interval = 7986, State = 0, intervalsBeforeStateChange = 0, 
lost4KPages = 825056 
 
Thirdly, additional tuning increase failures will occur. 
This condition may persist for long periods of time, until other 
STMM tuning activity brings the lost4KPages value back down to 
0. 
 
The lost4KPages value should always be 0 except when 
DATABASE_MEMORY = COMPUTED, and this will be addressed in this 
APAR.

**************************************************************** 
* USERS AFFECTED:                                              * 
* Systems with STMM tuning of Database Memory enabled          * 
* (SELF_TUNING_MEM = ON   AND  DATABASE_MEMORY = AUTOMATIC)    * 
**************************************************************** 
* PROBLEM DESCRIPTION:                                         * 
* See Error Description                                        * 
**************************************************************** 
* RECOMMENDATION:                                              * 
* If long periods exist where STMM is not tuning effectively   * 
* (see Error Description for symptom), upgrade to DB2 Version  * 
* 9.5 Fix pack 8 or higher.                                    * 
****************************************************************

DB2 Version 9.5 Fix Pack 8 for Linux, UNIX, and Windows
 DB2 Version 9.5 Fix Pack 9 for Linux, UNIX, and Windows
 DB2 Version 9.5 Fix Pack 10 for Linux, UNIX, and Windows
 

Problem first fixed in DB2 Version 9.5 Fix Pack 8

keiner bekannt / siehe Local-Fix

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

30.11.2010
11.08.2011
11.08.2011

9.5.FP8