DB2 FOR LUW / DB2FORLUW / B10 - DB2

Db2 might crash when freeing memory of certain sizes. Trap file
& db2diag.log will show the following functions on the top of
the stack:

SQLO_MEM_POOL::diagnoseMemoryCorruptionAndCrash
SQLO_MEM_POOL::MemTreePut
sqlofmblkEx

and an error message reported to db2diag.log will indicate a
corrupt pool free tree:

FUNCTION: DB2 UDB, SQO Memory Management,
sqloDiagnoseFreeBlockFailure, probe:999
MESSAGE : Memory validation failure, diagnostic file dumped.
DATA #1 : String, 28 bytes
Corrupt pool free tree node.

Problem is specific to Db2 11.1 Mod 4 FP4 (also iFix 001)
environments and is more likely to happen if DB_MEM_THRESH is
*not* set to 100 (which is the recommended value). One of the
code paths affected is backup - at the end of backup instance
might crash with the following functions on the top of the
stack:

SQLO_MEM_POOL::diagnoseMemoryCorruptionAndCrash
SQLO_MEM_POOL::MemTreePut
sqlofmblkEx
sqluxFreeAllMem
sqlubcka

****************************************************************
* USERS AFFECTED:                                              *
* All users                                                    *
****************************************************************
* PROBLEM DESCRIPTION:                                         *
* See Error Description                                        *
****************************************************************
* RECOMMENDATION:                                              *
* Upgrade to DB2 Version 11.1 Mod 4 Fix pack 5                 *
****************************************************************

Verify DB_MEM_THRESH for the database and set it to 100 if the
current value is different, which should greatly reduce the risk
of hitting the error.

For BACKUP scenarios, use a different size backup buffer e.g. 2
buffers more (or less) than the current value, which triggered
the crash.

not known / see Local fix

forerunner  : 
follow-up : 424AC6Ÿ IT30792 

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

12.03.2019
10.07.2019
10.07.2019