PM23556: LARGE CLIENTDELEGATE INSTANCES LEADING TO HEAP EXHAUSTION

APAR status

• Closed as program error.

Error description

• Error Message: Customer reports large instances of
  ClientDelegate and IOR objects persisting on heap even after the
  Services(EJBs) been evacuated. Issue is seen on 142 SR13 FP4.
  
  Large no. of instances of following objects was found during
  HeapDump Analysis:
  a com.ibm.CORBA.iiop.ClientDelegate
  b com.ibm.CORBA.iiop.ObjectKey
  c)com.ibm.rmi.IOR
  .
  Stack Trace: N/A
  .
  In Customer Scenario the two largest collections of objects in
  on heap dump were the a)SessionManager and b) SelectionManager.
  SessionManager was collecting sessions for a common EJB or
  server. The SelectionManager cached the IOR (indirect object
  reference) for RMI calls.
  
  Analysis of heapdumps taken over the issue revealed a possible
  leak in the following object graph:
  ------------------------------------------------------
  com.ibm.ws.util.ThreadPool$Worker @ 0xa50aaaf0  ORB.thread.pool
  : 393 JNI Global, Thread
  <HAT>00- <Java Local> com.ibm.ws.orb.WSExtendedServerDelegate @
  0x712a8378
  <HAT>00  '- clientSubcontractMappingFactory
  com.ibm.CORBA.iiop.ServerDelegate$ClientSubcontractMappingFactor
  y @ 0x712bbff0
  <HAT>00     '- cache
  com.ibm.jtc.orb.map.CacheFactories$Soft$FutureCacheImpl @
  0x71642518
  <HAT>00        '- map java.util.HashMap @ 0x71642530
  <HAT>00           '- elementData
  java.util.HashMap$Entry<OSB>262144<CSB> @ 0x83000008
  <HAT>00              <HAT>00- <OSB>41042<CSB>
  java.util.HashMap$Entry @ 0x9a304648
  ............
  
  - <Java Local> com.ibm.CORBA.iiop.ORB @ 0x712a2010
  <HAT>00  <HAT>00- fWLMPlugin com.ibm.ws.wlm.client.WLMClient @
  0x712a2350
  <HAT>00  <HAT>00  '- impl
  com.ibm.ws.cluster.router.selection.WLMClientForCommonRouterImpl
  @ 0x712a3718
  <HAT>00  <HAT>00     '- selectionMgr
  com.ibm.ws.cluster.router.selection.SelectionManager @
  0x71af5e90
  <HAT>00  <HAT>00        '- proxies java.util.WeakHashMap @
  0x71afc218
  <HAT>00  <HAT>00           '- elementData
  java.util.WeakHashMap$Entry<OSB>376832<CSB> @ 0x85800148
  ............
  

Local fix

Problem summary

• The "Soft" held ClientDelegate references in ORB's
  ServerDelegate led to a bloated memory footprint.
  

Problem conclusion

• This defect will be fixed in:
  1.4.2 SR13 FP8
  .
  The ClientDelegate cache in ServerDelegate  has been "Weak"end
  taking care to not loose functionality.
  .
  To obtain the fix:
  Install build 20101105 or later
  

Temporary fix

Comments

APAR Information

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

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

  PM23557 PM23558 PM23561

Fix information

• Fixed component name

  JAVA(1.3/1.4 CO

• Fixed component ID

  5648C9800

Applicable component levels

• R42A PSN

     UP

• R42L PSN

     UP

• R42W PSN

     UP

• R420 PSN

     UP