PK90778: CLASSCACHE LOOKUP IN REPOSITORYID CAUSES PERF DEGRADATION

APAR status

• Closed as program error.

Error description

• Error Message: The EJB methods deployed in different
  applications on the same server 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 in 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.
  .
  This problem can be seen from Java 142 SR_11 onwards.
  
  Stack Trace: javacore thread stack showing contention:
  "WebContainer : 135" (TID:0x50BFDFC0, sys_thread_t:0x4077A528,
  state:MW, native ID:0x6B4F) prio=5
  at
  com.ibm.rmi.util.RepositoryId$ClassNameToClassCache.get(Reposito
  ryId.java(Compiled Code))
  at
  com.ibm.rmi.util.RepositoryId.checkClassCache(RepositoryId.java(
  Compiled Code))
  at
  com.ibm.rmi.util.RepositoryId.getClassFromType(RepositoryId.java
  (Compiled Code))
  at
  com.ibm.rmi.iiop.CDRInputStream.fast_read_value(CDRInputStream.j
  ava(Compiled Code))
  at
  com.ibm.rmi.iiop.CDRInputStream.fast_read_abstract_interface(CDR
  InputStream.java(Compiled Code))
  at
  com.ibm.rmi.iiop.CDRInputStream.fast_read_abstract_interface(CDR
  InputStream.java(Compiled Code))
  at
  com.ibm.rmi.io.IIOPInputStream.readObjectDelegate(IIOPInputStrea
  m.java(Compiled Code))
  at
  com.ibm.rmi.io.IIOPInputStream.readObjectOverride(IIOPInputStrea
  m.java(Compiled Code))
  at
  java.io.ObjectInputStream.readObject(ObjectInputStream.java(Comp
  iled Code))
  at java.util.ArrayList.readObject(ArrayList.java(Compiled Code))
  at sun.reflect.GeneratedMethodAccessor58.invoke(Unknown Source)
  at
  sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethod
  AccessorImpl.java(Compiled Code))
  at java.lang.reflect.Method.invoke(Method.java(Compiled Code))
  at
  com.ibm.rmi.io.IIOPInputStream.invokeObjectReader(IIOPInputStrea
  m.java(Compiled Code))
  at
  com.ibm.rmi.io.IIOPInputStream.inputObjectUsingClassDesc(IIOPInp
  utStream.java(Compiled Code))
  at
  com.ibm.rmi.io.IIOPInputStream.inputObjectClassDesc(IIOPInputStr
  eam.java(Compiled Code))
  at
  com.ibm.rmi.io.IIOPInputStream.readSerializable(IIOPInputStream.
  java(Compiled Code))
  at
  com.ibm.rmi.io.IIOPInputStream.simpleReadObjectInternal(IIOPInpu
  tStream.java(Compiled Code))
  at
  com.ibm.rmi.io.IIOPInputStream.simpleReadObject(IIOPInputStream.
  java(Compiled Code))
  at
  com.ibm.rmi.io.ValueHandlerImpl.readValue(ValueHandlerImpl.java(
  Compiled Code))
  at
  com.ibm.rmi.iiop.CDRInputStream.read_value(CDRInputStream.java(C
  ompiled Code))
  at com.ibm.rmi.util.ProxyUtil.copyObject(ProxyUtil.java(Compiled
  Code))
  at
  com.ibm.rmi.util.ProxyUtil.invokeWithClassLoaders(ProxyUtil.java
  (Compiled Code))
  at
  com.ibm.CORBA.iiop.ClientDelegate.invoke(ClientDelegate.java(Com
  piled Code))
  at $Proxy155.ejbMethod(Unknown Source)
  at com.a.b.c.d._EJB_Stub.ejbMethod(_EJB_Stub.java(Compiled
  Code))
  .
  

Local fix

Problem summary

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

Problem conclusion

• This defect will be fixed in:
  1.4.2 SR13-4 (Linux AMD64)
  1.4.2 SR13-4 (Windows AMD64)
  1.4.2 SR13-4 (z/OS 64-bit)
  1.4.2 SR13-4
  .
  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 20090816 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:

  PK90779 PK90782 PK90852

Fix information

• Fixed component name

  LIN AMD 64 JAVA

• Fixed component ID

  620400103

Applicable component levels

• R142 PSN

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