IBM Support

IV32346: WMQ 7.0.1.8 JAVA. HIGH CPU USAGE NOTICED FOR POOLSCAVENGERTHREAD

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APAR status

  • Closed as program error.

Error description

  • WMQ 7.0.1.8 Java. High CPU usage noticed for
    PoolScavenger thread or PoolScavenger thread appears to be hung
    in Javacore.
    

Local fix

  • Restart JVM allows for temporary relief.
    

Problem summary

  • ****************************************************************
    USERS AFFECTED:
    This issue effects uses of the WebSphere MQ classes for Java
    V7.0, V7.1 and V7.5 who are making use of Connection Pooling.
    
    Platforms affected:
    All Distributed (iSeries, all Unix and Windows) +Java +Java zOS
    ****************************************************************
    PROBLEM SUMMARY:
    The PoolScavenger thread controls when an MQ Connection is to
    be removed from the MQ Connection Pool either due to
    connection expiry or that the limit for the connection pool
    has been reached.
    
    When the PoolScavenger thread detected that a connection
    should be destroyed it attempted to cleanup the connection,
    but the connection was incorrectly marked as being in use by
    an application. This then caused the PoolScavenger thread to
    fail to remove the connection which resulted in the
    PoolScavenger thread looping in a tight loop as it attempted
    to remove that connection.
    
    A Javacore of the system showed that the PoolScavenger thread
    was constantly running rather than in a wait state. High CPU
    was also seen with this thread.
    

Problem conclusion

  • This APAR solves the issue by making sure that the connection
    is not marked as in use when it is added to the MQ Connection
    Pool.
    
    ---------------------------------------------------------------
    The fix is targeted for delivery in the following PTFs:
    
                       v7.0
    Platform           Fix Pack 7.0.1.10
    --------           --------------------
    Windows            U200352
    AIX                U853055
    HP-UX (PA-RISC)    U853082
    HP-UX (Itanium)    U853087
    Solaris (SPARC)    U853083
    Solaris (x86-64)   U853089
    iSeries            7.0.1.10
    Linux (x86)        U853084
    Linux (x86-64)     U853088
    Linux (zSeries)    U853085
    Linux (Power)      U853086
    zOS                7.0.1.10
    
                       v7.1
    Platform           Fix Pack 7.1.0.3
    --------           --------------------
    Windows            7.1.0.3
    AIX                7.1.0.3
    HP-UX (Itanium)    7.1.0.3
    Solaris (SPARC)    7.1.0.3
    Solaris (x86-64)   7.1.0.3
    iSeries            7.1.0.3
    Linux (x86)        7.1.0.3
    Linux (x86-64)     7.1.0.3
    Linux (zSeries)    7.1.0.3
    Linux (Power)      7.1.0.3
    zOS                7.1.0.3
    
    Platform           v7.5
    --------           --------------------
    Multiplatforms     7.5.0.1
    
    The latest available maintenance can be obtained from
    'WebSphere MQ Recommended Fixes'
    http://www-1.ibm.com/support/docview.wss?rs=171&uid=swg27006037
    
    If the maintenance level is not yet available information on
    its planned availability can be found in 'WebSphere MQ
    Planned Maintenance Release Dates'
    http://www-1.ibm.com/support/docview.wss?rs=171&uid=swg27006309
    ---------------------------------------------------------------
    

Temporary fix

Comments

APAR Information

  • APAR number

    IV32346

  • Reported component name

    WMQ AIX V7

  • Reported component ID

    5724H7221

  • Reported release

    701

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt

  • Submitted date

    2012-11-20

  • Closed date

    2012-11-30

  • Last modified date

    2012-11-30

  • 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

    WMQ AIX V7

  • Fixed component ID

    5724H7221

Applicable component levels

  • R701 PSY

       UP

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Document Information

Modified date:
30 November 2012