Fixes are available
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
Db2 Version 11.1 Mod4 Fix Pack4 iFix001 for Linux, UNIX, and Windows
Db2 Version 11.1 Mod 4 Fix Pack 4 for Linux, UNIX, and Windows
Db2 Version 11.1 Mod 4 Fix Pack 6 for Linux, UNIX, and Windows
Db2 Version 11.1 Mod 4 Fix Pack 5 for Linux, UNIX, and Windows
Db2 Version 11.1 Mod 4 Fix Pack 7 for Linux, UNIX, and Windows
APAR status
Closed as program error.
Error description
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           : 4295032808 bytes. Physical heap size             : 5139988480 bytes. Configured heap size           : 9320792064 bytes. Unreserved memory used by heap : 0 bytes. Unreserved memory left in set  : 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.
Local fix
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.
Problem summary
**************************************************************** * 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. * ****************************************************************
Problem conclusion
The complete fix for this problem first appears in DB2 Version 11.1.3.3 iFix001 and all the subsequent Fix Packs.
Temporary fix
Comments
APAR Information
APAR number
IT23954
Reported component name
DB2 FOR LUW
Reported component ID
DB2FORLUW
Reported release
B10
Status
CLOSED PER
PE
NoPE
HIPER
NoHIPER
Special Attention
NoSpecatt / Xsystem
Submitted date
2018-02-05
Closed date
2018-05-22
Last modified date
2019-04-30
APAR is sysrouted FROM one or more of the following:
APAR is sysrouted TO one or more of the following:
IT23988
Fix information
Fixed component name
DB2 FOR LUW
Fixed component ID
DB2FORLUW
Applicable component levels
RB10 PSN
UP
[{"Business Unit":{"code":"BU058","label":"IBM Infrastructure w\/TPS"},"Product":{"code":"SSEPGG","label":"DB2 for Linux- UNIX and Windows"},"Platform":[{"code":"PF025","label":"Platform Independent"}],"Version":"11.1","Line of Business":{"code":"LOB10","label":"Data and AI"}}]
Document Information
Modified date:
04 May 2022