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PK77937: CICS TRANSACTIONS STUCK WAITING IN DISPATCH FOR THE SO_TCB. CURRENT TASK ON SO TCB ISSUED A VERIFY FROM DFHSOIS.

A fix is available

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APAR status

  • Closed as program error.

Error description

  • DFHSOIS has issued a VERIFY call (in this case a
    gethostbyname) as a result of an OPEN SESSION from DFHWBCL to
    communicate with a server for a SOAP request.  The VERIFY
    call results in a TCPIP call to a DNS server.  The DNS server
    does not respond quickly, and the VERIFY request will wait
    for the TCPIP RESOLVERTIMEOUT value before the request is
    timed out.  Once it is timed out, if there is another DNS
    server in your setup, it will roll to the next DNS to satisfy
    the request.  Resolving the problem with the DNS is typically
    what is done to resolve this type of delay problem.  The
    RESOLVERTIMEOUT value can also be lowered (see TCPIP APAR
    PK29603) to reduce the amount of time the request will wait.
    This CICS APAR is being taken because DFHSOIS is repeating
    the VERIFY call 50 times, if it doesn't complete
    successfully, before it gives up and reports a failure back
    to the caller.  It appears the retry should only be done if
    CICS receives a TRY_AGAIN errno from TCPIP, but the retry is
    repeated for any error.
    
    Additional Symptom(s) Search Keyword(s):
    gethostbyaddr verify_ip_address tcp/ip
    KIXREVSWM
    

Local fix

Problem summary

  • ****************************************************************
    * USERS AFFECTED: All CICS users.                              *
    ****************************************************************
    * PROBLEM DESCRIPTION: Several dispatchable CICS transactions  *
    *                      are waiting to run on the SO TCB.       *
    ****************************************************************
    * RECOMMENDATION:                                              *
    ****************************************************************
    A CICS outbound HTTP SOAP request is made which causes a
    Verify_Ip_Address call to be issued. This results in a CEEPIPI
    call to invoke TCPIP function gethostbyname to the DNS server.
    At this point the task is running on the SO TCB. As the DNS
    server does not respond immediately the Verify request waits
    until the TCPIP RESOLVERTIMEOUT value has elapsed.
    When it does, an error response of 'HOST_NOT_FOUND' is returned
    and the Verify request is re-issued. This loop can be repeated
    up to 5 times.
    During this time any other tasks started that need to run on the
    SO TCB are dispatched but will then have to wait for the current
    task to complete.
    Depending on the RESOLVERTIMEOUT value and number of iterations
    through the 5 loop cycle these tasks may have to wait up to a
    maximum of 2.5 minutes. Whilst the tasks are waiting in a
    dispatchable state they cannot be purged.
    For a response of 'HOST_NOT_FOUND' the Verify request should not
    be re-issued, this should only be done for TRY_AGAIN responses.
    Additional Keywords: AWST abendAWST PK39051
    

Problem conclusion

  • DFHSOIS has been changed so that the CEEPIPI call to invoke the
    TCPIP function 'gethostbyname' will only be repeated up to a
    maximum of 5 times for TRY_AGAIN responses.
    

Temporary fix

  • FIX AVAILABLE BY PTF ONLY
    

Comments

APAR Information

  • APAR number

    PK77937

  • Reported component name

    CICSTS V3 Z/OS

  • Reported component ID

    5655M1500

  • Reported release

    500

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt

  • Submitted date

    2008-12-31

  • Closed date

    2009-04-06

  • Last modified date

    2009-05-02

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

    PK62143

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

    UK45408

Modules/Macros

  •    DESSOIS  DFHSOIS
    

Fix information

  • Fixed component name

    CICSTS V3 Z/OS

  • Fixed component ID

    5655M1500

Applicable component levels

  • R400 PSY UK45408

       UP09/04/09 P F904

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 May 2009