PH13588: VSAM RLS TO PRESERVE QUIESCED STATE OF DATASET

Obtain the fix for this APAR.

APAR status

• Closed as program error.

Error description

• VSAM RLS to preserve quiesced state of dataset
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED: All CICS users.                              *
  ****************************************************************
  * PROBLEM DESCRIPTION: CICS attempts OPEN requests against     *
  *                      RLS files which have quiesced           *
  *                      data sets.                              *
  ****************************************************************
  When a data set is quiesced by RLS, associated files are
  set to CLOSED UNENABLED state by CICS. A subsequent unquiesce
  command will reset the file status to CLOSED ENABLED, and allow
  a file control command to implicitly reopen the file.
    In the customer's case, their exit programs reset the file
  status to CLOSED ENABLED then allowed applications to attempt
  further commands against the file. This resulted in a large
  number of open requests being received by file control for
  data sets that were quiesced and unavailable for use. The
  first of these requests enqs on the FCTE of the file, then calls
  DFHFCRO to switch to the FO TCB and issue the OPEN SVC to
  VSAM. While this is progressing, other requests against the
  same file are made to wait on the enqueue held by the first
  task.
  If the OPEN request is delayed within VSAM (due to a large
  number of concurrent OPEN SVCs from multiple CICS systems, and
  delays at the data set level) the waiting tasks can time out
  with a DTIMOUT. The OPEN request itself could also fail with a
  reason code of x'B1' meaning data set quiesced, and the task
  switch back from the FO TCB and dequeue from the FCTE. This in
  turn allows other tasks to attempt the same operation.
  
  Keywords: msgDFHFC6001 msgDFHFC0500 FC6001 FC0500 00B1
  

Problem conclusion

• CICS has been changed to record that a data set has been
  quiesced (and unquiesced) by a new flag within the DSNB control
  block. When this is turned on, DFHFCRO can avoid switching to
  the FO TCB and then issuing an OPEN request to SMSVSAM. This
  improves the pathlength within CICS file open processing, and
  reduces contention on the FO TCB. It also reduces the
  time that the enqueue is held upon a file's FCTE, so decreasing
  the likelihood that other tasks waiting on this enqueue will
  time out and be abended.
    The CICS TS 5.3 Data Areas manual will be updated in the
  section for the DSN.Under flag byte FCTDNFL1, a new flag
  bit will be added as follows:
  (40) ..1. .... FCTDNQUI "X'20'" Data set is quiesced ,
    The same change will be made to the CICS TS 5.4 and 5.5 Data
  Areas manuals.
  

Temporary fix

Comments

• ×**** PE20/06/03 FIX IN ERROR. SEE APAR PH26064  FOR DESCRIPTION
  

APAR Information

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

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

  UI65863 UI65864 UI65865

Modules/Macros

• DFHDSND  DFHDTLX  DFHFCBD  DFHFCCA  DFHFCDL  DFHFCDN  DFHFCDO
  DFHFCDR  DFHFCDTS DFHFCDUF DFHFCFL  DFHFCFR  DFHFCFS  DFHFCIR
  DFHFCL   DFHFCLF  DFHFCLJ  DFHFCM   DFHFCMT  DFHFCN   DFHFCNQ
  DFHFCQU  DFHFCRC  DFHFCRC2 DFHFCRD  DFHFCRO  DFHFCRP  DFHFCRR
  DFHFCRS  DFHFCRV  DFHFCSD  DFHFCST  DFHFCU   DFHFCVR  DFHFCVS
  DFHFCXDF
  

Fix information

• Fixed component name

  CICS TS Z/OS V5

• Fixed component ID

  5655Y0400

Applicable component levels

• R000 PSY UI65864

     UP19/10/24 P F910

• R100 PSY UI65863

     UP19/10/15 P F910

• R200 PSY UI65865

     UP19/10/15 P F910

Fix is available

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