PM20539: CLASSLOADER MEMORY LEAK.

Fixes are available

APAR status

Closed as program error.

Error description

Classloader memory leak in Naming CacheManager in the servant
region. Leak occurs if applications are started and stopped many
times such as in a stress test.
Example of leak:
0x14c52e700 com/ibm/ws/naming/jcache/CacheKey@66c366c3
  0x14ad88ad0 java/util/HashMap$Entry@67146714
   0x14471a228 java/util/HashMap$Entry@55905590
    0x14e2a8d58 [Ljava/util/HashMap$Entry;@711b711b
      0x128487320 class
com/ibm/ws/naming/jcache/CacheManager@6bc46bc4
       0x128a99668
org/eclipse/osgi/internal/baseadaptor/DefaultClassLoader@7f5f7f5
f
        [truncating at system class LEAK]

Local fix

Problem summary

****************************************************************
* USERS AFFECTED:  Users of IBM WebSphere Application Server   *
*                  Network Deployment versions 7.0 on z/OS     *
****************************************************************
* PROBLEM DESCRIPTION: Slow memory leak of classloader in      *
*                      CacheManager when applications are      *
*                      started and stopped repeatedly.         *
****************************************************************
* RECOMMENDATION:                                              *
****************************************************************
Naming cache is used to speed up lookup.  For java namespace
caches, CacheManager uses the associated context classloader
as part of the key to lookup the cache instance.  This works as
design on distributed platforms.  However, since the
NameServerImpl,  which registers an deployment listener to
clears out caches during the application stop, runs in the
control region, while the CacheManager and runs in the servant
region, the classloader did not get clear out on z/OS.  Thus, a
minor memory leak of classloader is seen in CacheManager in the
servant region on z/OS when applications is started and
stopped repeatedly over time.  This memory leak should only be
a concern during stress test.  Under normal usage, this leak
does not have a noticeable impact.

Problem conclusion

The ServantNameServiceImpl registers a listener to remove
classloader used as cache key in the CacheManager when
application is stopped.  The slow memory leak of classloaders
in servant region is removed.

APAR PM20539 is currently targeted for inclusion in Service
Level 7.0.0.15 of WebSphere Application Server.

Please refer to URL:
//www.ibm.com/support/docview.wss?rs=404&uid=swg27006970
for Fix Pack availability.

Temporary fix

Comments

APAR Information

APAR number
PM20539
Reported component name
WEBSPHERE FOR Z
Reported component ID
5655I3500
Reported release
700
Status
CLOSED PER
PE
NoPE
HIPER
NoHIPER
Special Attention
NoSpecatt
Submitted date
2010-08-13
Closed date
2010-11-08
Last modified date
2011-04-04

APAR is sysrouted FROM one or more of the following:
APAR is sysrouted TO one or more of the following:

PM43071

Fix information

Fixed component name
WEBSPHERE FOR Z
Fixed component ID
5655I3500

Applicable component levels

R700 PSY UK65060
UP11/03/04 P F103

Fix is available

Select the PTF appropriate for your component level. You will be required to sign in. Distribution on physical media is not available in all countries.

[{"Business Unit":{"code":"BU053","label":"Cloud & Data Platform"},"Product":{"code":"SS7K4U","label":"WebSphere Application Server for z\/OS"},"Platform":[{"code":"PF025","label":"Platform Independent"}],"Version":"7.0","Line of Business":{"code":"LOB45","label":"Automation"}}]

Document Information

Modified date:
24 October 2021

Tips

PM20539: CLASSLOADER MEMORY LEAK.

Fixes are available

Subscribe

APAR status

Closed as program error.

Error description

Local fix

Problem summary

Problem conclusion

Temporary fix

Comments

APAR Information

APAR number

Reported component name

Reported component ID

Reported release

Status

PE

HIPER

Special Attention

Submitted date

Closed date

Last modified date

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

Fixed component ID

Applicable component levels

R700 PSY UK65060

Fix is available

Select the PTF appropriate for your component level. You will be required to sign in. Distribution on physical media is not available in all countries.

Document Information

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