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PH01832: High CPU observed on the dmgr process driven by VisualizationEngine.CacheWorkItemsTP thread.

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You can track all active APARs for this component.

 

APAR status

  • Closed as program error.

Error description

  • High CPU observed on the dmgr process driven by
    VisualizationEngine.CacheWorkItemsTP thread and the
    javacores show entries similar to:
    
    "VisualizationEngine.CacheWorkItemsTP : 21"
    J9VMThread:0x0000000005C2E500,
    j9thread_t:0x00007F30F8042D80,
    java/lang/Thread:0x00000007072ABD30, state:R, prio=5
    (java/lang/Thread getId:0x2CD, isDaemon:true)
    (native thread ID:0x89AB, native priority:0x5, native
    policy:UNKNOWN, vmstate:CW, vm thread flags:0x00000001)
    (native stack address range from:0x00007F3152335000,
    to:0x00007F3152376000, size:0x41000)
    CPU usage total: 41682.791755135 secs
    Heap bytes allocated since last GC cycle=0 (0x0)
    Java callstack:
    at java/util/HashMap.getEntry(HashMap.java:477(Compiled
    Code))
    at java/util/HashMap.containsKey(HashMap.java:462(Compiled
    Code))
    at
    com/ibm/ws/xd/visualizationengine/cacheservice/cacheimpl/Ser
    verStatsCache$ServerStatsAsyncClient.start(ServerStatsCache.
    java:1460)
    at
    com/ibm/ws/xd/visualizationengine/cacheservice/cacheimpl/Ser
    verStatsCache.initializeServer(ServerStatsCache.java:629)
    at
    com/ibm/ws/xd/visualizationengine/cacheservice/cacheimpl/Ser
    verStatsCache.initializeEntityCache(ServerStatsCache.java:53
    7)
    at
    com/ibm/ws/xd/visualizationengine/cacheservice/AbstractIndex
    Cache$InitializeEntityWorker.run(AbstractIndexCache.java:146
    5)
    at
    com/ibm/ws/util/ThreadPool$Worker.run(ThreadPool.java:1892(C
    ompiled Code))
    

Local fix

  • N/A
    

Problem summary

  • ****************************************************************
    * USERS AFFECTED:  All users of IBM WebSphere Application      *
    *                  Server WAS ND edition- Virtual              *
    *                  Enterprise/IM Component                     *
    ****************************************************************
    * PROBLEM DESCRIPTION: High CPU observed on the dmgr process   *
    *                      driven by                               *
    *                      VisualizationEngine.CacheWorkItemsTP    *
    *                      thread.                                 *
    ****************************************************************
    * RECOMMENDATION:                                              *
    ****************************************************************
    High CPU observed on the dmgr process driven by
    VisualizationEngine.CacheWorkItemsTP thread and the javacores
    show entries similar to:
    
    "VisualizationEngine.CacheWorkItemsTP : 21"
    J9VMThread:0x0000000005C2E500, j9thread_t:0x00007F30F8042D80,
    java/lang/Thread:0x00000007072ABD30, state:R, prio=5
    (java/lang/Thread getId:0x2CD, isDaemon:true)
    (native thread ID:0x89AB, native priority:0x5, native
    policy:UNKNOWN, vmstate:CW, vm thread flags:0x00000001)
    (native stack address range from:0x00007F3152335000,
    to:0x00007F3152376000, size:0x41000)
    CPU usage total: 41682.791755135 secs
    Heap bytes allocated since last GC cycle=0 (0x0)
    Java callstack:
    at java/util/HashMap.getEntry(HashMap.java:477(Compiled Code))
    at java/util/HashMap.containsKey(HashMap.java:462(Compiled
    Code))
    at
    com/ibm/ws/xd/visualizationengine/cacheservice/cacheimpl/ServerS
    tatsCache$ServerStatsAsyncClient.start(ServerStatsCache.java:146
    0)
    at
    com/ibm/ws/xd/visualizationengine/cacheservice/cacheimpl/ServerS
    tatsCache.initializeServer(ServerStatsCache.java:629)
    at
    com/ibm/ws/xd/visualizationengine/cacheservice/cacheimpl/ServerS
    tatsCache.initializeEntityCache(ServerStatsCache.java:537)
    at
    com/ibm/ws/xd/visualizationengine/cacheservice/AbstractIndexCach
    e$InitializeEntityWorker.run(AbstractIndexCache.java:1465)
    at
    com/ibm/ws/util/ThreadPool$Worker.run(ThreadPool.java:1892(Compi
    led Code))
    

Problem conclusion

  • The synchronization around the HashMap referenced in the stack
    was incorrect and allowed the map to grow unbounded resulting in
    the high cpu condition on the dmgr. The
    visualization.cacheservice component has been modified to
    properly guard the HashMap object to avoid the high cpou
    condition.
    
    The fix for this APAR is currently targeted for inclusion in fix
    packs 9.0.0.9 and 8.5.5.15.  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 number

    PH01832

  • Reported component name

    WEBS APP SERV N

  • Reported component ID

    5724H8800

  • Reported release

    850

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt / Xsystem

  • Submitted date

    2018-08-16

  • Closed date

    2018-10-25

  • Last modified date

    2018-10-25

  • 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

       UP

[{"Business Unit":{"code":"BU053","label":"Cloud \u0026 Data Platform"},"Product":{"code":"SSEQTP","label":"WebSphere Application Server"},"Platform":[{"code":"PF025","label":"Platform Independent"}],"Version":"850","Line of Business":{"code":"LOB36","label":"IBM Automation"}}]

Document Information

Modified date:
17 October 2021