IZ22312: ORB PERFORMANCE DEGRADATION WHILE MARSHALLING DEEPLY NESTED OBJE CTS

APAR status

• Closed as program error.

Error description

• Error Message: The customer setup included a pair of EJBS
  deployed in 2 different applications on the same Server.
  The EJB methods pass around heavily nested objects which trigger
  a lot of internal cache lookup. Under high load, the javacores
  reveal a bottleneck in com/ibm/rmi/util/RepositoryId .java's
  checkClassCache() method which result is very slow requests
  processing times.
  While this problem was reported on collocated EJB calls, the
  same problem might happen in the remote invocation scenario too.
  .
  Stack Trace: javacore thread stack showing contention:
  "WebContainer : 0" (TID:0x000000012443C300,
  sys_thread_t:0x000000011ED89A90, state:B, native
  ID:0x00000000000E216D) prio=5
       at
  com/ibm/rmi/util/RepositoryId.checkClassCache(RepositoryId.java:
  658(Compiled Code))
   at
  com/ibm/rmi/util/RepositoryId.getClassFromType(RepositoryId.java
  :617(Compiled Code))
   at
  com/ibm/rmi/iiop/CDRInputStream.fast_read_value(CDRInputStream.j
  ava:1990(Compiled Code))
   <deleted for readability>
  
   at
  java/io/ObjectInputStream.readObject(ObjectInputStream.java:357(
  Compiled Code))
   at java/util/TreeMap.buildFromSorted(TreeMap.java:1623(Compiled
  Code))
   at java/util/TreeMap.buildFromSorted(TreeMap.java:1563(Compiled
  Code))
   at java/util/TreeMap.readObject(TreeMap.java(Compiled Code))
  
   at sun/reflect/GeneratedMethodAccessor120.invoke(Bytecode
  PC:40(Compiled Code))
   at
  sun/reflect/DelegatingMethodAccessorImpl.invoke(DelegatingMethod
  AccessorImpl.java:43(Compiled Code))
   at java/lang/reflect/Method.invoke(Method.java:603(Compiled
  Code))
   at
  com/ibm/rmi/io/IIOPInputStream.invokeObjectReader(IIOPInputStrea
  m.java:1689(Compiled Code))
   <deleted for readability>
  
   at
  com/ibm/rmi/io/IIOPInputStream.simpleReadObjectLoop(IIOPInputStr
  eam.java:480(Compiled Code))
   at
  com/ibm/rmi/io/IIOPInputStream.simpleReadObject(IIOPInputStream.
  java:434(Compiled Code))
   at
  com/ibm/rmi/io/ValueHandlerImpl.readValue(ValueHandlerImpl.java:
  201(Compiled Code))
   at
  com/ibm/rmi/iiop/CDRInputStream.read_value(CDRInputStream.java:1
  583(Compiled Code))
   at
  com/ibm/rmi/util/ProxyUtil.copyObject(ProxyUtil.java:451(Compile
  d Code))
   at
  com/ibm/rmi/util/ProxyUtil.invokeWithClassLoaders(ProxyUtil.java
  :755(Compiled Code))
   at
  com/ibm/CORBA/iiop/ClientDelegate.invoke(ClientDelegate.java:115
  5(Compiled Code))
   at
  com/a/b/c/d/_EJB1_Stub.ejbMethod(_EJB1_Stub.java:332(Compiled
  Code))
   ...
  .
  

Local fix

• If the customer scenario reveals slow response times for
  _collocated_ EJB methods (inside WAS), then setting the
  classloader policy to single in conjunction with setting
  pass_by_reference to true will work around the issue.
  

Problem summary

• The slow processing of requests was caused by the prevalent
  cache design .
  

Problem conclusion

• This defect will be fixed in:
  5.0.0 SR8
  .
  The cache design was overhauled to allow for more concurrent
  access as also the classloading-order which was refactored to
  prevent possible repetition of searches.
  .
  To obtain the fix:
  Install build 20080702 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:

  PK66121 PK66122 PK66123 PK66124 PK68826

Fix information

• Fixed component name

  JAVA 5 ORB

• Fixed component ID

  620500123

Applicable component levels

• R500 PSN

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