DB2 FOR LUW / DB2FORLUW / A50 - DB2

The AIX default user data (memory) limit is 128MB.  While DB2 
overrides this to unlimited for the main database server 
process, db2sysc, this does not affect fenced processes such as 
db2fmp, db2vend.  If the 128MB user data limit is in effect for 
DB2 fenced processes, they may become unstable (out of memory 
errors, traps).  This causes various errors in applications and 
DB2 functionality that depend on their successful execution.  In 
many cases the libraries that execute within the fenced 
processes require more than 128MB, and so are vulnerable to this 
constraint. 
 
DB2 will address this by overriding a default 128MB user data 
limit to "unlimited".  It will not override other customized 
settings which may be intentionally put in place by an 
administrator. 
 
Note that the inheritance of a user data limit may not be 
intuitive due to DB2's startup processing. 
- in DPF and pureScale environments, most user limits for fenced 
processes will be those of the DB2 instance ID. 
- in other environments, i.e. single partition DB2, most user 
limits for fenced processes will be those of the user ID which 
issued db2start.  this can be any user in the DB2 SYSADM group

**************************************************************** 
* USERS AFFECTED:                                              * 
* DB2 systems running on the AIX platform                      * 
**************************************************************** 
* PROBLEM DESCRIPTION:                                         * 
* See Error Description                                        * 
**************************************************************** 
* RECOMMENDATION:                                              * 
* Upgrade to DB2 Version 10.5 Fix Pack 7 or implement          * 
* workaround                                                   * 
****************************************************************

ensure that the user data limit for any user in the DB2 SYSADM 
group is set to unlimited.  Note that db2 must be recycled 
(db2stop/db2start) in a new shell session after any change in 
user data limits is made.  Issue "ulimit -d" before starting the 
instance to check that the desired change is in effect. 
 
the user data limit for a process can be checked with the pstat 
command on AIX.  For example : 
 
# pstat -a | grep db2fmp 
114 a 72012 78006 78006 200 200 1 db2fmp 
 
The first column is the process' slot in the process table, the 
third column is the Process ID in hexadecimal.  Given the 
process slot number, use the pstat command to list the process 
information . The ulimit details are listed in the Resource 
Limits section: 
 
    # pstat -u 120 
 ... 
    RESOURCE LIMITS AND COUNTERS 
... 
max data:0x08000000 max stk:0x10000000 max 
file(blks):0x003fffffffffffff 
... 
 
The above max_data setting of 0x08000000 indicates the default 
AIX user data limit of 128MB is in place.  On the other hand, 
output such as the following, showing a value of 0x7fffffff, 
would indicate a setting of "unlimited" is in effect 
 
    max data:0x7fffffff  max stk:0x02000000  max 
file(blks):0x003fffffffffffff

Problem first fixed in DB2 Version 10.5 Fix Pack 7

See Local Fix

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

30.04.2015
18.02.2016
18.02.2016