Fixes are available
Db2 Version 11.5 Mod 4 Fix Pack 0 for Linux, UNIX, and Windows
Db2 Version 11.5 Mod 5 Fix Pack 0 for Linux, UNIX, and Windows
Db2 Version 11.1 Mod 4 Fix Pack 6 for Linux, UNIX, and Windows
Db2 Version 11.5 Mod 5 Fix Pack 1 for Linux, UNIX, and Windows
Db2 Version 11.5 Mod 6 Fix Pack 0 for Linux, UNIX, and Windows
Db2 Version 11.5 Mod 7 Fix Pack 0 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
Performance of MON_GET_TABLE/MON_GET_INDEX table functions will be affected if those are executed concurrently against databases with high number (tens of thousands or more) of table control blocks (TCBs) loaded into memory and run with non-NULL tabschema or tabname arguments. Loaded TCBs can be listed by: $ db2pd -db <db_name> -tcbstats or counted with: $ db2 "select count(*) from table(mon_get_table('','',-1))" During concurrent execution response time will degrade due to a contention on heap memory allocation by malloc function. A backtrace on threads of Db2 engine (db2sysc) obtained with $ db2pd -stack all or a debugger (gstack/procstack) will show threads with ossStrCompWithPads near the top of the stack, e.g. ... free_common _ossMemFree ossStrCompWithPads sqlrwFilteredTableIterator::execute ... monGetTable ... or: ... malloc_common _ossMemAlloc ossStrCompWithPads sqlrwFilteredTableIterator::execute ... monGetIndex ...
Local fix
Database deactivation and activation will remove TCBs from memory which temporarily should improve the response time of those functions. On AIX platform performance can be also improved by switching to the multiheap malloc implementation, which requires 1. Adding extra environmental variables to Db2 profile, sqllib/userprofile (persistent during across instance upgrades) or sqllib/db2profile (which will be replaced by default during db2iupdt) export MALLOCOPTIONS=buckets,multiheap:4 export MALLOCBUCKETS=number_of_buckets:128,bucket_sizing_factor:64,bloc ks_per_bucket:1024 2. Setting appending those two options to DB2ENVLIST db2set DB2ENVLIST="MALLOCOPTIONS MALLOCBUCKETS" 3. Restarting the instance for settings to be picked up by Db2 engine.
Problem summary
**************************************************************** * USERS AFFECTED: * * all * **************************************************************** * PROBLEM DESCRIPTION: * * See Error Description * **************************************************************** * RECOMMENDATION: * * Upgrade to 11.5m4fp0 or higher * ****************************************************************
Problem conclusion
Upgrade to 11.5m4fp0 or higher
Temporary fix
Comments
APAR Information
APAR number
IT31704
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
2020-01-30
Closed date
2020-06-30
Last modified date
2020-06-30
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
RB50 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:
03 May 2022