DB2 FOR LUW / DB2FORLUW / B10 - DB2

The memory assigned to DB2_HADR_BUF_SIZE db2 registry is being 
allocated from dbheap during database activation/connection. 
Any changed to this registry become effective after db2 restart. 
 
This defect can cause a) unnecessary re-allocation of the 
receive 
buffer leading to the Standby running out of memory or b) memory 
corruption due to not allocating memory for the receive buffer 
when 
necessary. 
 
Symptom a) DBHEAP OUT OF MEMORY 
 
This defect causes re-allocation of DB2_HADR_BUF_SIZE memory 
during standby db re-connect after communication failure when 
there is no change to the setting. This causes double allocation 
of memory from dbheap. 
 
And since some customers set the value of this DB2_HADR_BUF_SIZE 
registry to a higher number than the default of 2Xlogbufsz, it 
may cause out of dbheap memory errors on Standby causing db2 to 
go down. 
 
the messages in db2diag.log may look like this: 
 
2018-01-21-01.31.15.322975-300 E12975694A696        LEVEL: 
Warning 
PID     : 18612304             TID : 20562          PROC : 
db2sysc 0 
INSTANCE: db2inst1             NODE : 000           DB   : 
SAMPLE 
HOSTNAME: standbyhost 
EDUID   : 20562                EDUNAME: db2hadrs.0.0 (SAMPLE) 0 
FUNCTION: DB2 UDB, SQO Memory Management, 
sqloMemLogPoolConditions, probe:30 
DATA #1 : <preformatted> 
Out of memory failure for Database Heap (DBHEAP) on node 0. 
Requested block size &#160; &#160; &#160; &#160; &#160; : 4295032808 bytes. 
Physical heap size &#160; &#160; &#160; &#160; &#160; &#160; : 5139988480 bytes. 
Configured heap size &#160; &#160; &#160; &#160; &#160; : 9320792064 bytes. 
Unreserved memory used by heap : 0 bytes. 
Unreserved memory left in set &#160;: 470089728 bytes. 
 
This is most likely to occur when using a very large 
DB2_HADR_BUF_SIZE up to the 4GB recommended limit, in 
conjunction with low db memory. 
 
With this fix, we will not re-allocate memory if no change to 
the setting. 
 
Symptom b) MEMORY CORRUPTION 
 
Under the following conditions: 
 
1. logbufsz on the Primary database is exactly 32768 
 
2. DB2_HADR_BUF_SIZE is unset on the Standby 
 
memory corruption occurs and the Standby database 
crashes with an FODC_Trap or FODC_Panic as a result.

**************************************************************** 
* USERS AFFECTED:                                              * 
* ALL                                                          * 
**************************************************************** 
* PROBLEM DESCRIPTION:                                         * 
* See Error Description                                        * 
**************************************************************** 
* RECOMMENDATION:                                              * 
* The complete fix for this problem first appears in DB2       * 
* Version 11.1.3.3 iFix001 and all the subsequent Fix Packs.   * 
****************************************************************

Symptom a) DBHEAP OUT OF MEMORY 
 
As a temporary workaround, please apply one of the following: 
 
1. Increase database memory 
 
or 
 
2. Use log spooling instead of using large DB2_HADR_BUF_SIZE 
 
Symptom b) MEMORY CORRUPTION 
 
Set the DB2_HADR_BUF_SIZE registry variable on the Standby to 
any value other than the default of 16, e.g. 
 
db2set DB2_HADR_BUF_SIZE=65536 
 
The Standby receive buffer will be correctly allocated when the 
Standby is brought back up.

Db2 Version 11.1 Mod3 Fix Pack3 iFix001 for Linux, UNIX, and Windows
 Db2 Version 11.1 Mod3 Fix Pack3 iFix002 for Linux, UNIX, and Windows
 

The complete fix for this problem first appears in DB2 Version 
11.1.3.3 iFix001 and all the subsequent Fix Packs.

not known / see Local fix

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

05.02.2018
22.05.2018
30.04.2019