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PK47243: CFQS TASK HUNG IN A RESUMED_EARLY STATE

A fix is available

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APAR status

  • Closed as program error.

Error description

  • RLS files hang in 'being quiesced' state. A dump shows that the
    CICS Quiesce Send task, CFQS is stuck in a RESUMED_EARLY state.
    There are no Quiesce Receive elements, FCQRE 's, but there are
    pages of Quiesce Send elements, FCQSE 's. With the CFQS task in
    this resumed early state, none of the Quiesce Send requests will
    complete.
    .
    A dump taken with a trap from PQ93593 shows that the CFQS task
    became RESUMED_EARLY following a call to DFHFCQI for an
    INITIATE_QUIESCE request. Prior to this, CFQS was in a WAIT_MVS
    suspend, waiting on an ECB list containing 2 ECBs.  Both of
    these ECBs are posted.
    .
    The problem seems to have occurred during Post exit processing.
    It appears that DFHDSWKT is entered at essentially the same time
    to POST both ECBs. The first POST causes the TASK_STATE to
    change from SUSPENDED to DISPATCHABLE. On return from DFHDSWKT,
    DFHDSPX will drive DFHDSCAL (ADD_READY_CHAINS) to add the task
    to the Dispatchable chains. However, the TASK_STATE is checked
    again, and the 2nd POST has now occurred which changed the
    TASK_STATE from DISPATCHABLE to RESUMED_EARLY. So the code to
    add the task to the Dispatchable chains is bypassed.
    

Local fix

Problem summary

  • ****************************************************************
    * USERS AFFECTED: All.                                         *
    ****************************************************************
    * PROBLEM DESCRIPTION: The CFQS task is stuck in a resumed     *
    *                      early state, resulting in many tasks    *
    *                      suspended with a reason FCQUIESC, and   *
    *                      a large number of FCQSEs.               *
    ****************************************************************
    * RECOMMENDATION:                                              *
    ****************************************************************
    The CFQS task is stuck in a resumed_early state. This can leave
    a number of data sets in a 'being quiesced' state. A number of
    tasks have added an FCQSE to the list of work elements to be
    actioned by CFQS, and are suspended with reason FCQUIESC,
    waiting for the FCQSE to be actioned by the CFQS task, and so
    resume the suspended tasks.
    The CFSQ task issued the RLS QUIESCE request and waited on a
    list of ecbs. One of the ECBs was posted when new work was
    added to the FCQSE chain, this used an MVS POST. The other
    ECB was posted by RLS after the RLS QUIESCE had completed,
    this used the DFHCPOST mechanism which does not serialise
    through the MVS POST.
    Both ECBs were posted very close together. The first put the
    task into a dispatchable state, but before it could be
    added to the dispatchable chain, the second post was driven
    which set the task to a 'resumed early' state.
    Routine ADD_READY_CHAINS only adds the task to the dispatchable
    chain if its task state is dispatchable, so it is left
    permanently in a 'resumed early' state.
    Additional keywords:
    RESUMED_EARLY SEND ELEMENTS TASK_STATE DFHFCQI exit DFHDSPX
    HANG HUNG
    

Problem conclusion

  • The ADD_READY_CHAINS logic in macro DFHDSTSK has been amended
    to also allow a task being in a 'resumed_early' state to be
    added to the dispatchable chain.
    

Temporary fix

  •             *********
                * HIPER *
                *********
    FIX AVAILABLE BY PTF ONLY
    

Comments

APAR Information

  • APAR number

    PK47243

  • Reported component name

    CICSTS V3 Z/OS

  • Reported component ID

    5655M1500

  • Reported release

    400

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    YesHIPER

  • Special Attention

    NoSpecatt

  • Submitted date

    2007-06-18

  • Closed date

    2007-07-20

  • Last modified date

    2007-08-03

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

    PK40508

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

    UK27315

Modules/Macros

  •    DFHDSAUT DFHDSCPX DFHDSDS3 DFHDSSR  DFHDSTCB
    DFHDSTSK
    

Fix information

  • Fixed component name

    CICSTS V3 Z/OS

  • Fixed component ID

    5655M1500

Applicable component levels

  • R400 PSY UK27315

       UP07/07/25 P F707

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:
03 August 2007