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PH03693: CICS WLP RUNNING OUT OF THREADS

A fix is available

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APAR status

  • Closed as program error.

Error description

  • After upgrade the CICS Liberty from 17.0.0.4 to 18.0.0.1
    CICS WLP is using more threads than before. CICS was started
    with the new Liberty release, and the CICS region went out of
    threads (the service was degraded, the liberty server was not
    responding).
    
    The problem that it can see from the dumps is that an OSGi
    application is attempting to run within the same JVMSERVER
    Liberty.  This has been allowed for a while now and looks to
    have been ok until this point.  With the change in the Liberty
    thread model it appears to be more aggressive at getting
    threads than before and so its preloaded all the threads up to
    the threadlimit.  This means that when DFHSJTH attempts to
    allocate another thread its unable to do this and so its
    suspended waiting on threads that may never be freed by Liberty.
    

Local fix

  • Increase THREADLIMIT value on the JVMSERVER resource.
    

Problem summary

  • ****************************************************************
    * USERS AFFECTED: All CICS Users.                              *
    ****************************************************************
    * PROBLEM DESCRIPTION: OSGi Applications within a Liberty      *
    *                      JVM server hang because Liberty has     *
    *                      all the threads.                        *
    ****************************************************************
    An OSGi Application is installed within a Liberty JVM server.
    When the OSGi Application attempts to execute it hangs due to
    no JVM threads being available to process it.  Liberty is
    currently using all the available threads which blocks the
    application.
    

Problem conclusion

  • Liberty JVM servers have been updated so that if an OSGi
    application is installed then 10% of threads will be reserved
    for its use.
    
    The JVMProfile option:
    
    -Dcom.ibm.cics.jvmserver.wlp.reserve.thread.percentage
    
    can be used to configure the percentage reserved.  This can be
    set from 1 to 50.
    
    The CICS Transaction Server for z/OS v5.3 Knowledge Center, CICS
    Transaction Server for z/OS v5.4 Knowledge Center and CICS
    Transaction Server for z/OS v5.5 Knowledge Center have
    been updated as follows:
    
    JVM system properties
    Table 1 has been updated to add the new property:
    
    com.ibm.cics.jvmserver.wlp.reserve.thread.percentage
    
    which is supported in Liberty JVM servers only
    
    Plus the following description is added:
    
    Reserves a percentage of the threadlimit of the JVMSERVER for
    use by OSGi Applications.  The value can be between 1% and 50%.
    

Temporary fix

Comments

APAR Information

  • APAR number

    PH03693

  • Reported component name

    CICS TS Z/OS V5

  • Reported component ID

    5655Y0400

  • Reported release

    00L

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt / Xsystem

  • Submitted date

    2018-10-08

  • Closed date

    2019-03-05

  • Last modified date

    2019-04-02

  • APAR is sysrouted FROM one or more of the following:

  • APAR is sysrouted TO one or more of the following:

    UI61673 UI61674 UI61676 UI61677 UI61678

Modules/Macros

  • DFHSJJS  DFJ@H351 DFJ@H352 DFJ@H427 DFJ@H561 DFJ@H563
    

Fix information

  • Fixed component name

    CICS TS Z/OS V5

  • Fixed component ID

    5655Y0400

Applicable component levels

  • R000 PSY UI61673

       UP19/03/08 P F903

  • R00D PSY UI61674

       UP19/03/08 P F903

  • R100 PSY UI61676

       UP19/03/06 P F903

  • R10D PSY UI61677

       UP19/03/06 P F903

  • R200 PSY UI61678

       UP19/03/06 P F903

Fix is available

  • Select the PTF appropriate for your component level. You will be required to sign in. Distribution on physical media is not available in all countries.

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Document Information

Modified date:
02 April 2019