DB2 FOR LUW / DB2FORLUW / A10 - DB2

When a configuration has an insufficient database memory 
setting, DB2 overrides the setting, calculating a database 
memory size which will support the configuration - including a 
5% overflow.  One of the main uses of the overflow is for 
package cache overhead - which can be as much 100% in the worst 
case.  If package cache is 10000 4K pages or 40MB, it may need 
an additional 40MB from database memory overflow to support 
package cache requirements. 
 
This APAR will add additional overflow for package cache - the 
amount will be the equivalent of the package cache setting - and 
only for the specific case of insufficient database memory 
settings.  Note this has no impact on STMM configurations, where 
overflow is already maintained by STMM. 
 
When using a fixed database_memory setting, monitor the 
"Unreserved" column in db2pd -db <db> -memsets output.  If this 
value approaches 0, the system is in danger of database overflow 
exhaustion, and application requests may fail with SQL0973 
errors. 
 
Case with sufficient overflow (Unreserved is 245MB out of a 
configured size of 1489MB) 
Memory Sets: 
Name         Address            Id          Size(Kb)   Key 
DBP    Type   Unrsv(Kb) 
SAMPLE       0x0700000040000000 2097196     1489920     0x0 
0      1      245760 
 
Case with insufficient overflow (Unreserved is 2MB out of a 
configured size of 1489MB) 
Memory Sets: 
Name         Address            Id          Size(Kb)   Key 
DBP    Type   Unrsv(Kb) 
SAMPLE       0x0700000040000000 2097196     1489920     0x0 
0      1      1842 
 
Example db2diag.log entry: 
FUNCTION: DB2 UDB, access plan manager, sqlra_cache_fill_pkg, 
probe:600 
RETCODE : ZRC=0x8B0F0007=-1961951225=SQLO_NOMEM_PCKCACHEH 
          "No memory available in 'Package Cache'" 
          DIA8300C A memory heap error has occurred.

**************************************************************** 
* USERS AFFECTED:                                              * 
* Systems using a fixed Database Memory setting without the    * 
* self-tuning memory manager (STMM) enabled                    * 
**************************************************************** 
* PROBLEM DESCRIPTION:                                         * 
* See Error Description                                        * 
**************************************************************** 
* RECOMMENDATION:                                              * 
* Upgrade to DB2 Version 10.1 Fix pack 3                       * 
****************************************************************

Ensure the database memory setting is sufficient to support the 
configuration.  If encountering SQL0973 due to no memory in 
package cache, database_memory can be increased dynamically to 
allow for additional overflow.  Do not increase the package 
cache setting as this will tend to exacerbate the problem.

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
 

Problem first fixed in DB2 Version 10.1 Fix Pack 3

See Local Fix

forerunner  : APAR is sysrouted TO one or more of the following: IC95222 
follow-up : 

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

02.04.2013
04.12.2013
04.12.2013