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PK92827: TASK IN FCXCSUSP SUSPEND WAIT IS NEVER PURGED EVEN WHEN DEFINED WITH SPURGE(YES) AND DTIMOUT TIME HAS PASSED.

A fix is available

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APAR status

  • Closed as program error.

Error description

  • You have a task which is in a FCXCSUSP wait.  Your transaction
    is defined with SPURGE(YES) and the DTIMOUT time has passed yet
    the task is never purged automatically by CICS' DTIMOUT.
    

Local fix

Problem summary

  • ****************************************************************
    * USERS AFFECTED: All CICS users.                              *
    ****************************************************************
    * PROBLEM DESCRIPTION: Some tasks, that are waiting on the     *
    *                      FCXCSUSP or FCXDSUSP resource types,    *
    *                      are never purged by CICS even when      *
    *                      they are defined with SPURGE(YES)       *
    *                      and the DTIMOUT interval has expired.   *
    ****************************************************************
    * RECOMMENDATION:                                              *
    ****************************************************************
    When a task makes a request requiring exclusive control
    of a VSAM control interval, CICS will suspend it with a
    resource type of FCXCSUSP or FCXDSUSP if the control interval
    is already under shared or exclusive control by another task.
    
    FCXDSUSP is used, rather than FCXCSUSP, when CICS detects
    a deadlock between waiting tasks.
    
    Normally, a task suspended with FCXCSUSP or FCXDSUSP will be
    purged by CICS if its transaction definition specifies a
    DTIMOUT time-out value and has SPURGE(YES),
    
    However, if VSAM returns an 080x14 error response from the
    dataset request then CICS sets the task to be protected against
    purging and the SPURGE and DTIMOUT settings are ignored.
    For these error cases it is preferable to purge the other tasks
    involved in the wait so CICS can retry the request that returned
    the error. Purging the task that received the VSAM
    error could cause problems such as leaving the base cluster
    and an AIX path out of step.
    
    There was nothing to indicate to the user that the task was in
    a protected FCXCSUSP or FCXDSUSP wait that would never be
    purged by the CICS DTIMOUT time-out.
    
    Additional keywords: FCXCSUSP FCXDSUSP FCXCPROT FCXDPROT
    DTIMOUT SPURGE
    

Problem conclusion

  • DFHFCVS makes the call to Dispatcher to suspend a task for
    the FCXCSUSP or FCXDSUSP VSAM exclusive control wait types.
    Two new wait types, FCXCPROT and FCXDPROT, have been added.
    These will be used for exclusive control waits when VSAM has
    returned a 080x14 error and CICS has set the tasks to be
    protected against a DTIMOUT purge.
    
    The code has been changed to include tests on the existing
    VSWA_080X14 flag to determine which wait type to use.
    If the flag is ON then FCXCPROT is used rather than FCXCSUSP
    and, similarly, FCXDPROT is used rather than FCXDSUSP.
    
    
    Changes will be made to the CICS Transaction Server for z/OS
    Version 3 Release 2, Problem Determination Guide, SC34-6826-01,
    as follows:
    
    An entry will be added for wait resource types FCXCPROT and
    FCXDPROT after the entry for FCXCSUSP and FCXDSUSP
    in the table "Resources on which a suspended task might be
    waiting" in the section "The resources on which tasks in a
    CICS system can wait".
    
    Resource Purge Resource Suspending  DSSR call Task Where to
    type           name     module      and WLM        look next
                                        wait type
    
    FCXCPROT No,  file ID   DFHFCVS  WAIT_OLDC IO User Investigating
    and      No                                        file control
    FCXDPROT                                           waits
    
    
    An entry will be added for wait resource types FCXCPROT and
    FCXDPROT, after the entry for FCXCSUSP and FCXDSUSP,
    in the table "Resource types for file control waits" in the
    section "Investigating file control waits".
    
    Resource      Description                       RLS or non-RLS
                                                    access mode
    
    FCXCPROT or   The task is waiting for exclusive   Non-RLS
    FCXDPROT      control of a VSAM control interval
                  and VSAM has detected a error with
                  the AIX, base cluster or upgrade
                  set.
    
    The section headed "Resource types FCXCSUSP and FCXDSUSP -
    VSAM exclusive control waits", will be renamed and changed as
    follows:
    
    "Resource types FCXCSUSP, FCXDSUSP, FCXCPROT and FCXDPROT - VSAM
    exclusive control waits"
    
    "If your task is waiting on resource type FCXCSUSP, FCXDSUSP,
    FCXCPROT or FCXDPROT it means that it cannot get exclusive
    control of a VSAM control interval at the present time.
    Another task already has shared or exclusive control of the
    control interval, so your task is suspended pending the release
    of that control interval.
    
    An exclusive control wait on these resource types occurs within
    CICS, unlike the similar wait on FCIOWAIT, which occurs within
    VSAM. See Resource type FCIOWAIT - wait for VSAM I/O (non-RLS).
    
    FCXCPROT or FCXDPROT waits indicate that VSAM has detected
    an error in the base cluster, AIX or upgrade set. In these
    cases, it is not advisable to purge the requests because the
    dataset can be left in an inconsistent state. You should
    purge other tasks involved in the wait to allow CICS to retry
    the VSAM requests for those with FCXCPROT and FCXDPROT waits.
    
    Unlike the FCXCSUSP and FCXDSUSP types, tasks waiting with
    a resource type of FCXCPROT or FCXDPROT will not be purged
    if they are suspended for longer than their DTIMOUT value.
    
    If you find that exclusive control conflicts occur too often
    in your system, consider changing the programming logic so that
    applications are less likely to have exclusive control for long
    periods.
    
    Waiting on this resource can occur only for files accessed in
    non-RLS mode.
    
    The possibility that a task is deadlocked, waiting on itself or
    another task for release of the control interval, is dealt with
    in the next section."
    

Temporary fix

  • FIX AVAILABLE BY PTF ONLY
    

Comments

APAR Information

  • APAR number

    PK92827

  • 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

    2009-07-30

  • Closed date

    2009-10-30

  • Last modified date

    2009-12-02

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

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

    PK99166 UK51602 UK51603

Modules/Macros

  •    DFHFCVS  DFHFCVS1 EYU0NLHS
    

Publications Referenced
SC34682601    

Fix information

  • Fixed component name

    CICSTS V3 Z/OS

  • Fixed component ID

    5655M1500

Applicable component levels

  • R50M PSY UK51603

       UP09/11/07 P F911

  • R500 PSY UK51602

       UP09/11/07 P F911

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 December 2009