PQ98295: CACHE SHOULD POOL LARGE OBJECTS THAT ARE ALLOCATED FOR MANAGING DISK CACHE.

 Fixes are available

PQ98295; 5.0.2.8: Improve Dynamic Cache disk offload JVM memory utilization.
5.1.1.17: WebSphere Application Server V5.1.1 Cumulative Fix 17 for AIX
5.1.1.17: WebSphere Application Server V5.1.1 Cumulative Fix 17 for HP-UX
5.1.1.19: WebSphere Application Server V5.1.1 Cumulative Fix 19 for Linux
5.1.1.16: WebSphere Application Server V5.1.1 Cumulative Fix 16 for AIX
5.1.1.18: WebSphere Application Server V5.1.1 Cumulative Fix 18 for AIX
5.1.1.18: WebSphere Application Server V5.1.1 Cumulative Fix 18 for HP-UX
5.1.1.18: WebSphere Application Server V5.1.1 Cumulative Fix 18 for Solaris
5.1.1.18: WebSphere Application Server V5.1.1 Cumulative Fix 18 for Windows
5.1.1.18: WebSphere Application Server V5.1.1 Cumulative Fix 18 for Linux
5.1.1.17: WebSphere Application Server V5.1.1 Cumulative Fix 17 for Linux
5.1.1.17: WebSphere Application Server V5.1.1 Cumulative Fix 17 for Solaris
5.1.1.17: WebSphere Application Server V5.1.1 Cumulative Fix 17 for Windows
6.0.2: WebSphere Application Server V6.0 Refresh Pack 2 for AIX platforms
5.0.2.17: WebSphere Application Server 5.0.2 Cumulative Fix 17 for Solaris
5.0.2.17: WebSphere Application Server 5.0.2 Cumulative Fix 17 for Windows
5.0.2.14: WebSphere Application Server 5.0.2 Cumulative Fix 14 for Solaris
5.1.1.10: WebSphere Application Server V5.1.1 Cumulative Fix 10 for Windows
5.1.1.10: WebSphere Application Server V5.1.1 Cumulative Fix 10 for AIX
5.1.1.8: WebSphere Application Server 5.1.1 Cumulative Fix 8 for AIX
5.0.2.14: WebSphere Application Server 5.0.2 Cumulative Fix 14 for Linux
5.1.1.19: WebSphere Application Server V5.1.1 Cumulative Fix 19 for AIX
5.1.1.8: WebSphere Application Server 5.1.1 Cumulative Fix 8 for Windows
5.1.1.19: WebSphere Application Server V5.1.1 Cumulative Fix 19 for Windows
5.1.1.8: WebSphere Application Server 5.1.1 Cumulative Fix 8 for HP-UX
5.1.1.9: WebSphere Application Server V5.1.1 Cumulative Fix 9 for Solaris
5.1.1.8: WebSphere Application Server 5.1.1 Cumulative Fix 8 for Solaris
5.0.2.15: WebSphere Application Server 5.0.2 Cumulative Fix 15 for Windows
5.0.2.15: WebSphere Application Server 5.0.2 Cumulative Fix 15 for Solaris
5.0.2.15: WebSphere Application Server 5.0.2 Cumulative Fix 15 for AIX
5.1.1.9: WebSphere Application Server V5.1.1 Cumulative Fix 9 for AIX
5.0.2.15: WebSphere Application Server 5.0.2 Cumulative Fix 15 for Linux
6.0.2: WebSphere Application Server V6.0 Refresh Pack 2 for HP-UX platforms
6.0.2: WebSphere Application Server V6.0 Refresh Pack 2 for OS/400 platforms
5.0.2.12: WebSphere Application Server 5.0.2 Cumulative Fix 12
5.1.1.6: WebSphere Application Server Version 5.1.1 Cumulative Fix 6
5.1.1.7: WebSphere Application Server Version 5.1.1 Cumulative Fix 7
5.0.2.14: WebSphere Application Server 5.0.2 Cumulative Fix 14 for HP-UX
5.0.2.14: WebSphere Application Server 5.0.2 Cumulative Fix 14 for AIX
5.1.1.4: WebSphere Application Server Version 5.1.1 Cumulative Fix 4
5.1.1.9: WebSphere Application Server V5.1.1 Cumulative Fix 9 for Windows
5.0.2.17: WebSphere Application Server 5.0.2 Cumulative Fix 17 for HP-UX
5.0.2.17: WebSphere Application Server 5.0.2 Cumulative Fix 17 for AIX
5.1.1.11: WebSphere Application Server V5.1.1 Cumulative Fix 11 for AIX
5.0.2.17: WebSphere Application Server 5.0.2 Cumulative Fix 17 for Linux
5.1.1.10: WebSphere Application Server V5.1.1 Cumulative Fix 10 for HP-UX
6.0.2: WebSphere Application Server V6.0 Refresh Pack 2 for Solaris platforms
5.1.1.10: WebSphere Application Server V5.1.1 Cumulative Fix 10 for Linux
5.1.1.9: WebSphere Application Server V5.1.1 Cumulative Fix 9 for HP-UX
5.1.1.9: WebSphere Application Server V5.1.1 Cumulative Fix 9 for Linux
6.0.0.3: WebSphere Application Server V6.0.0 Fix Pack 3
5.0.2.16: WebSphere Application Server 5.0.2 Cumulative Fix 16 for HP-UX
5.1.1.12: WebSphere Application Server V5.1.1 Cumulative Fix 12 for Windows
5.0.2.16: WebSphere Application Server 5.0.2 Cumulative Fix 16 for Solaris
5.0.2.16: WebSphere Application Server 5.0.2 Cumulative Fix 16 for Windows
5.0.2.16: WebSphere Application Server 5.0.2 Cumulative Fix 16 for AIX
5.1.1.11: WebSphere Application Server V5.1.1 Cumulative Fix 11 for Windows
5.1.1.16: WebSphere Application Server V5.1.1 Cumulative Fix 16 for Solaris
5.0.2.18: WebSphere Application Server 5.0.2 Cumulative Fix 18 for Solaris
5.1.1.11: WebSphere Application Server V5.1.1 Cumulative Fix 11 for Linux
5.0.2.18: WebSphere Application Server 5.0.2 Cumulative Fix 18 for Windows
5.0.2.18: WebSphere Application Server 5.0.2 Cumulative Fix 18 for HP-UX
5.0.2.18: WebSphere Application Server 5.0.2 Cumulative Fix 18 for AIX
5.1.1.16: WebSphere Application Server V5.1.1 Cumulative Fix 16 for Windows
5.1.1.14: WebSphere Application Server V5.1.1 Cumulative Fix 14 for Solaris
5.0.2.14: WebSphere Application Server 5.0.2 Cumulative Fix 14 for Windows
5.1.1.12: WebSphere Application Server V5.1.1 Cumulative Fix 12 for AIX
5.1.1.12: WebSphere Application Server V5.1.1 Cumulative Fix 12 for Linux
5.1.1.12: WebSphere Application Server V5.1.1 Cumulative Fix 12 for HP-UX
5.1.1.12: WebSphere Application Server V5.1.1 Cumulative Fix 12 for Solaris
5.1.1.11: WebSphere Application Server V5.1.1 Cumulative Fix 11 for Solaris
5.1.1.13: WebSphere Application Server V5.1.1 Cumulative Fix 13 for AIX
5.1.1.13: WebSphere Application Server V5.1.1 Cumulative Fix 13 for Windows
5.0.2.13: WebSphere Application Server 5.0.2 Cumulative Fix 13
5.1.1.13: WebSphere Application Server V5.1.1 Cumulative Fix 13 for HP-UX
5.1.1.15: WebSphere Application Server V5.1.1 Cumulative Fix 15 for Solaris
5.1.1.13: WebSphere Application Server V5.1.1 Cumulative Fix 13 for Solaris
5.1.1.13: WebSphere Application Server V5.1.1 Cumulative Fix 13 for Linux
5.1.1.14: WebSphere Application Server V5.1.1 Cumulative Fix 14 for AIX
5.1.1.14: WebSphere Application Server V5.1.1 Cumulative Fix 14 for Linux
5.1.1.14: WebSphere Application Server V5.1.1 Cumulative Fix 14 for Windows
6.0.2: WebSphere Application Server V6.0 Refresh Pack 2 for Windows platforms
6.0.2: WebSphere Application Server V6.0 Refresh Pack 2 for Linux platforms
5.1.1.15: WebSphere Application Server V5.1.1 Cumulative Fix 15 for Windows
5.0.2.18: WebSphere Application Server 5.0.2 Cumulative Fix 18 for Linux
5.1.1.11: WebSphere Application Server V5.1.1 Cumulative Fix 11 for HP-UX
5.1.1.14: WebSphere Application Server V5.1.1 Cumulative Fix 14 for HP-UX
5.1.1.8: WebSphere Application Server 5.1.1 Cumulative Fix 8 for Linux
5.0.2.15: WebSphere Application Server 5.0.2 Cumulative Fix 15 for HP-UX
6.0.1.2: WebSphere Application Server Version 6.0.1 Fix Pack 2
5.0.2.16: WebSphere Application Server 5.0.2 Cumulative Fix 16 for Linux
5.1.1.10: WebSphere Application Server V5.1.1 Cumulative Fix 10 for Solaris
5.1.1.15: WebSphere Application Server V5.1.1 Cumulative Fix 15 for AIX
5.1.1.15: WebSphere Application Server V5.1.1 Cumulative Fix 15 for HP-UX
5.1.1.16: WebSphere Application Server V5.1.1 Cumulative Fix 16 for HP-UX
5.1.1.16: WebSphere Application Server V5.1.1 Cumulative Fix 16 for Linux
6.0.1: WebSphere Application Server Version 6.0 Refresh Pack 1
5.1.1.15: WebSphere Application Server V5.1.1 Cumulative Fix 15 for Linux
5.1.1.19: WebSphere Application Server V5.1.1 Cumulative Fix 19 for HP-UX



APAR status
Closed as program error.

Error description
problem summary: excessive garbage collection and possibility
for out of memory error

details: cache should pool large objects (6x 10M) that are
allocated for managing disk cache.These objects are released and
reallocated when the cache is cleared. Allocating 10M objects
after the server has been running for long timmight be a strain
on garbage collection.
And if GC cannot defragment memory for this large allocation
when the cache is cleared, it might result in disabling disk
cache.
Local fix
no local fix available
Problem summary
****************************************************************
* USERS AFFECTED: All WebSphere Application Server Users       *
*                 using Dynamic Cache and the disk             *
*                 offload function.                            *
****************************************************************
* PROBLEM DESCRIPTION: Improve Dynamic Cache disk offload      *
*                      JVM memory utilization to prevent       *
*                      potential JVM memory fragmentation.     *
****************************************************************
* RECOMMENDATION:                                              *
****************************************************************
JVM memory fragmentation leading to possible JVM
out-of-memory exceptions or high GC activity.
Problem conclusion
During high disk offload
demand, the high rate
of allocation / deallocation of resources might
cause the JVM heap to become unusally
fragmented.
The high allocation / deallocation rate could also
overwhelm the JVM GC handler.
In rare cases, this could result in a permanent
memory allocation failure.
This APAR will do the following:
- Reduce the JVM memory requirements for
the disk offload function.
- Reduce the JVM memory allocation / deallocation
cycles from the disk offload classes.
- Reduces disk offload initial file system
requirements by 80%.

---------
Important
---------
This APAR changes the disk offload
file format. You must manually delete
the disk offload files from your
system. The default location
for these files is:
[install_root]/AppServer/temp
/[node_name]/[server_name]/_dynacache
You must delete all files and
sub-directories under the _dynacache
directory.
Temporary fix Comments
APAR information
APAR number PQ98295
Reported component name WAS NETWRK DEPL
Reported component ID 5630A3601
Reported release 00S
Status CLOSED PER
PE NoPE
HIPER NoHIPER
Special Attention NoSpecatt
Submitted date 2004-12-10
Closed date 2004-12-22
Last modified date 2004-12-22

APAR is sysrouted FROM one or more of the following:

APAR is sysrouted TO one or more of the following:

Modules/Macros

Publications Referenced

Fix information

Applicable component levels
R00A PSY    UP
R00H PSY    UP
R00I PSY    UP
R00P PSY    UP
R00S PSY    UP
R00W PSY    UP


Document Information


Product categories: Software > Application Servers > Distributed Application & Web Servers > WebSphere Application Server > General
Operating system(s):
Software version: 00S
Software edition:
Reference #: PQ98295
IBM Group: Software Group
Modified date: Dec 22, 2004