|
Problem IC76118
|
Status: Closed |
BACK GROUND SYSTEM APPS GET SQL1226N TOO OFTEN ESPECIALLY WHEN THERE ARE MANY FAST WRITER EDUS |
| product: |
DB2 FOR LUW / DB2FORLUW / 970 - DB2 |
| Problem description: |
APAR IC69285 added a limit on back ground system applications
(such as asynchronous index cleanup, admin task scheduler,
health monitor) in v9.7 fp4. This limit is determined
dynamically based on workload and sometimes it is too low
resulting in too many SQL1226N errors being encountered.
When the limit is reached, a new background task cannot be
started until others are finished.
Fast writer EDUs are background system applications that are
used by new event monitor types added in DB2 v9.7. The number of
fast writer EDUs started at database activation is based on the
number of logical CPUs and logical nodes hosted on a machine.
Due to this APAR, these fast writer EDUs are being counted
towards the limit on background system applications which can
mean that other background applications cannot run as they will
receive a SQL1226N error.
In this example, the autonomic computing daemon that is trying
to connect to the database to run back ground jobs.
2011-04-25-12.00.44.655369-240 I2051096A465 LEVEL: Info
PID : 24183550 TID : 1029 PROC : db2sysc
INSTANCE: db2inst1 NODE : 000
EDUID : 1029 EDUNAME: db2ipccm
FUNCTION: DB2 UDB, base sys utilities,
sqeAgentServices::RequestAgentForAppl, probe:1459
MESSAGE : ZRC=0xFFFFFB36=-1226
DATA #1 : <preformatted>
The number of background tasks has reached the limit of 61, will
try again later.
0 200 80 80 80 78 2 |
| Problem Summary: |
****************************************************************
* USERS AFFECTED: *
* This APAR is more likely to be hit on machines with more *
* than 8 processors per logical node. *
****************************************************************
* PROBLEM DESCRIPTION: *
* See above. *
****************************************************************
* RECOMMENDATION: *
* Upgrade to v9.7 fp5. *
**************************************************************** |
| Local Fix: |
Disable the limit on background system applications
using the following registry variable setting.
db2set DB2_PMODEL_SETTINGS=MAX_BACKGROUND_SYSAPPS:500
This is a dynamic registry variable setting that will be picked
up immediately without restarting the instance. |
| available fix packs: |
DB2 Version 9.7 Fix Pack 5 for Linux, UNIX, and Windows
DB2 Version 9.7 Fix Pack 6 for Linux, UNIX, and Windows
DB2 Version 9.7 Fix Pack 7 for Linux, UNIX, and Windows
DB2 Version 9.7 Fix Pack 8 for Linux, UNIX, and Windows
DB2 Version 9.7 Fix Pack 9 for Linux, UNIX, and Windows
DB2 Version 9.7 Fix Pack 9a for Linux, UNIX, and Windows
DB2 Version 9.7 Fix Pack 10 for Linux, UNIX, and Windows
|
| Solution |
In v9.7 fp5, the limit on background system applications is
turned off by default which was the behaviour in v9.7 fp3 or
earlier.
A fixed limit on background system applications can be set with
the following registry variable:
DB2_PMODEL_SETTINGS=MAX_BACKGROUND_SYSAPPS:<num>
where num is the limit. A reasonable number might be 100. The
instance must be restarted to pick up a change to this
registry variable. |
| Workaround |
not known / see Local fix |
| Timestamps |
Date - problem reported :
Date - problem closed :
Date - last modified :
| 02.05.2011
16.12.2011
16.12.2011 |
| Problem solved at the following versions (IBM BugInfos) |
9.7.FP3,
9.7.FP5,
9.7.FP5
|
| Problem solved according to the fixlist(s) of the following version(s) |
| 9.7.0.5
|
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