Fixes are available
APAR status
Closed as program error.
Error description
The issue defined in this APAR is related to problems with database activation on DPF environments (especially ones with many logical nodes on the same physical box). The problem persist only when INSTANCE_MEMORY is set to AUTOMATIC, and happens during database creation. During subsequent activation DB2 tries to start with extensively large bufferpools. We observe that those bufferpools are configured by configuration advisor (SmartGuide). Snippet from traces: 151237 data DB2 UDB config/install sqlf_db2cfgsg cei (3.3.6.87.2.40) pid 42551 tid 140737353975584 cpid 105 node 0 probe 40 bytes 32680 ... 0A62 703D 310A 4942 4D44 4546 4155 4C54 IBMDEFAULT 4250 3D34 3037 3333 3938 3A38 3139 320A BP=4073398:8192. 6E65 7757 413D 310A 5359 5344 4546 4155 newWA ... 6442 703D 310A 4942 4D44 4546 4155 4C54 IBMDEFAULT 4250 3D31 3030 303A 3831 3932 0A6F 6C64 BP=1000:8192.old 5741 3D31 0A53 5953 4445 4641 554C 5455 WA The calculation in sqlf_db2cfgsg function might end up in to high values which later on results in oversized memory for the DB. We have here underwrap problem during compute of bufferpools parameters. The underwrap is caused by SHEAPTHRES parameter which influences memory available for bufferpool area (for DPF systems using legacy SHEAPTHRES, the value is configured to 25% of machine size, spread across partitions). As the consequence, everything else will be configured to minimum since SHEAPTHRES takes up the entire 25% default, and furthermore we have the underwrap problem mentioned earlier. Problem above may cause paging and might result in system hang. Once this happens, we might observe OOM kille in action:
Local fix
You can do one of following: 1) Disable automatic configuration: db2set DB2_ENABLE_AUTOCONFIG_DEFAULT=OFF 2) Create database with "autoconfigure using mem_percent " clause: db2 create db <db> autoconfigure using mem_percent <50-90> apply db only
Problem summary
**************************************************************** * USERS AFFECTED: * * DPF * **************************************************************** * PROBLEM DESCRIPTION: * * See Error Description * **************************************************************** * RECOMMENDATION: * * Upgrade to Db2 version 11.1m4fp6 * ****************************************************************
Problem conclusion
The problem was first fixed in Db2 version 11.1m4fp6
Temporary fix
Comments
APAR Information
APAR number
IT17317
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
2016-10-03
Closed date
2021-02-24
Last modified date
2021-02-24
APAR is sysrouted FROM one or more of the following:
APAR is sysrouted TO one or more of the following:
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