PK33697: INTERMITTENT ILLOGIC CONDITIONS RETURNED TO THE APPLICATION ON A READNEXT FOR AN ESDS FILE.

Obtain the fix for this APAR.

APAR status

• Closed as program error.

Error description

• Intermittently a readnext operation on an ESDS file receives
  an Illogic response from DFHFCFR.  The readnext is taking place
  at the same time a write is occurring.  The write acts as a put
  new, and it has not completed yet.  The readnext acts as a get
  sequential and it's positioned at the end of the previous CI.
  The HIRBA has already been updated for the put request, and the
  get sequential finishes up first and reads the end of file.  The
  get / readnext receives a vsam_request_error x'089C' and an
  Illogic is returned to the application.
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED: All.                                         *
  ****************************************************************
  * PROBLEM DESCRIPTION: On a READNEXT for an ESDS file          *
  *                      intermittent illogic error 089C         *
  *                      returned to the application.            *
  ****************************************************************
  * RECOMMENDATION:                                              *
  ****************************************************************
  An intermittent illogic error rc089C may be returned from VSAM
  when reading or browsing a file whilst a concurrent write is
  being performed. For the write, if a new CI is required, VSAM
  will first update of the high rba value for the dataset before
  adding the record to the new CI. So there exists a timing window
  whereby the high rba value points to the new CI which as yet
  only contains a end of file marker. A read or browse of this new
  CI based on the high rba value will result in VSAM returning an
  089C - an invalid control interval has been found.
  

Problem conclusion

• DFHFCVS has been updated so that a VSAM error code of 089C
  is treated just the same as a 0890 VSAM error code. This
  will ensure that the request to VSAM is attempted up to three
  more times in case the error is due to a timing window rather
  than to an actual error. If the error code is returned all three
  times, it will still be reported back to CICS.
  
  The CICS Transaction Server for z/OS, Version 3 Release 1, CICS
  Problem Determination Guide, SC34-6441-02. Part 2, Chapter 6:
  Dealing with waits, Section 7: Investigating file control waits.
  Make the following changes:-
  
  In "Table 6. Resource types for file control waits" change the
  row for FCDWWAIT as follows:-
  Resource = FCDWWAIT
  Description = The task is waiting for VSAM to complete update
                processing.
  RLS or non-RLS access mode = Non-RLS
  
  In further subsection "Resource type FCDWWAIT - wait for VSAM
  upgrade set activity" change the heading and following
  paragraphs to:
  
  Resource type FCDWWAIT-wait for VSAM to complete update
  processing
  
  If your task is waiting on resource type FCDWWAIT, it has
  received a VSAM response which might indicate that your task is
  trying to read a record. Depending on the VSAM response code
  either because (i) the read is via a VSAM path while this record
  is being updated by another request. This other request is
  updating the record either via the base or via another path. If
  VSAM has not yet completed the update, the content of the
  alternate index currently in use is no longer the same as the
  content of the base data set.
  Or (ii) a concurrent write to the end of a dataset is
  incomplete.
  
  This is a transient condition. CICS waits for all current update
  operations for this complete and retries the
  request twice. If the error continues after the request is
  retried, CICS assumes that there is a genuine error and returns
  a response of ILLOGIC to the application. Since ILLOGIC is a
  response to all unexpected VSAM errors, CICS also returns the
  VSAM response and reason codes (X'0890') or (X'089C') in bytes 2
  and 3 of EIBRCODE. These identify the cause of the ILLOGIC
  response.
  
  Waiting on this resource can occur only for files accessed in
  non-RLS mode.
  

Temporary fix

• FIX AVAILABLE BY PTF ONLY
  

Comments

APAR Information

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

  PK30448

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

  UK19849

Modules/Macros

•    DFHFCVS  DFHFCVS1
  

Fix information

• Fixed component name

  CICSTS 3.1 Z/OS

• Fixed component ID

  5655M1500

Applicable component levels

• R400 PSY UK19849

     UP06/11/25 P F611

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.