PI45575: HASHMAPS ARE NOT THREAD-SAVED IN ORG.APACHE.OPENJPA.DATACACHE.DATACACHEMANAGERIMPL

8.5.5.8: WebSphere Application Server V8.5.5 Fix Pack 8
8.5.5.9: WebSphere Application Server V8.5.5 Fix Pack 9
8.5.5.10: WebSphere Application Server V8.5.5 Fix Pack 10
8.5.5.11: WebSphere Application Server V8.5.5 Fix Pack 11
8.5.5.12: WebSphere Application Server V8.5.5 Fix Pack 12
8.5.5.13: WebSphere Application Server V8.5.5 Fix Pack 13
8.5.5.14: WebSphere Application Server V8.5.5 Fix Pack 14
8.5.5.15: WebSphere Application Server V8.5.5 Fix Pack 15
8.5.5.17: WebSphere Application Server V8.5.5 Fix Pack 17
8.5.5.20: WebSphere Application Server V8.5.5.20
8.5.5.18: WebSphere Application Server V8.5.5 Fix Pack 18
8.5.5.19: WebSphere Application Server V8.5.5 Fix Pack 19
8.5.5.16: WebSphere Application Server V8.5.5 Fix Pack 16
8.5.5.21: WebSphere Application Server V8.5.5.21

APAR status

• Closed as program error.

Error description

• HashMap which are used in the
  org.apache.openjpa.datacache.DataCacheManagerImpl are not thread
  safe. So multiple threads can add and get information from the
  _cacheable at the same time.
  
  This may lead to exceptions like:
  
  [7/22/15 8:45:07:146 CEST] 00000054 TimeoutManage I   WTRN0124I:
  When the timeout occurred the thread with which the transaction
  is, or was most recently, associated was Thread[WebContainer :
  7,5,main]. The stack trace of this thread when the timeout
  occurred was:
  
  java.util.HashMap.findNonNullKeyEntry(HashMap.java:605)
  java.util.HashMap.getEntry(HashMap.java:589)
  java.util.HashMap.get(HashMap.java:575)
  org.apache.openjpa.datacache.DataCacheManagerImpl.isCachable(Dat
  aCacheManagerImpl.java:145)
  org.apache.openjpa.datacache.DataCacheManagerImpl.selectCache(Da
  taCacheManagerImpl.java:128)
  org.apache.openjpa.datacache.DataCacheStoreManager.initialize(Da
  taCacheStoreManager.java:358)
  org.apache.openjpa.kernel.DelegatingStoreManager.initialize(Dele
  gatingStoreManager.java:112)
  org.apache.openjpa.kernel.ROPStoreManager.initialize(ROPStoreMan
  ager.java:57)
  org.apache.openjpa.kernel.BrokerImpl.initialize(BrokerImpl.java:
  1051)
  org.apache.openjpa.kernel.BrokerImpl.find(BrokerImpl.java:1009)
  org.apache.openjpa.kernel.BrokerImpl.find(BrokerImpl.java:931)
  org.apache.openjpa.jdbc.kernel.JDBCStoreManager.load(JDBCStoreMa
  nager.java:1033)
  com.ibm.ws.persistence.jdbc.kernel.WsJpaJDBCStoreManager.load(Ws
  JpaJDBCStoreManager.java:143)
  org.apache.openjpa.jdbc.sql.AbstractResult.load(AbstractResult.j
  ava:280)
  ......
  

Local fix

• n/a
  

Problem summary

• ****************************************************************
  * USERS AFFECTED:  All users of IBM WebSphere Application      *
  *                  Server V8.5.5 who make use of the OpenJPA   *
  *                  DataCache.                                  *
  ****************************************************************
  * PROBLEM DESCRIPTION: The OpenJPA DataCacheManagerImpl        *
  *                      class (DataCache) can cause an          *
  *                      infinite loop when checking if          *
  *                      classes are cachable.                   *
  ****************************************************************
  * RECOMMENDATION:                                              *
  ****************************************************************
  When the OpenJPA DataCache is used, and under heavy load (many
  threads) there exists the change that some threads might
  become hung when the DataCache is accessed. An example of a
  hung thread might look like this:
  INFO "ClientConnection - 9" prio=10 tid=0x00007f33d400e000
  nid=0x8d9 runnable [0x00007f32db1ef000]
  INFO java.lang.Thread.State: RUNNABLE
  INFO at java.util.HashMap.getEntry(Unknown Source)
  INFO at java.util.HashMap.get(Unknown Source)
  INFO at
  org.apache.openjpa.datacache.DataCacheManagerImpl.isCachable(Dat
  aCacheManagerImpl.java:145)
  INFO at
  org.apache.openjpa.datacache.DataCacheManagerImpl.selectCache(Da
  taCacheManagerImpl.java:128)
  INFO at
  org.apache.openjpa.datacache.DataCacheStoreManager.initialize(Da
  taCacheStoreManager.java:358)
  INFO at
  org.apache.openjpa.kernel.DelegatingStoreManager.initialize(Dele
  gatingStoreManager.java:112)
  INFO at
  org.apache.openjpa.kernel.ROPStoreManager.initialize(ROPStoreMan
  ager.java:57)
  INFO at
  org.apache.openjpa.kernel.BrokerImpl.initialize(BrokerImpl.java:
  1027)
  INFO at
  org.apache.openjpa.kernel.BrokerImpl.find(BrokerImpl.java:985)
  INFO at
  org.apache.openjpa.kernel.BrokerImpl.find(BrokerImpl.java:907)
  The hung thread(s) occur because a HashMap used by DataCache
  is not thread safe.
  

Problem conclusion

• With this fix, code has been added to OpenJPA to ensure the
  HashMap used by the OpenJPA DataCache is properly synchronized
  (made thread safe).
  
  The fix for this APAR is currently targeted for
  inclusion in Service Level (Fix Pack) 8.5.5.8 of WebSphere
  Application Server version 8.5.5.
  
  Please refer to the recommended updates page for delivery
  information:
  http://www.ibm.com/support/docview.wss?rs=180&uid=swg27004980
  

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:

Fix information

• Fixed component name

  WEBS APP SERV N

• Fixed component ID

  5724H8800

Applicable component levels

• R850 PSY

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