PH67146: LOG EDIT USER EXIT DFSFLGE0 MIGHT ENTER AN INFINITE LOOP DUE TO A TIMING ISSUE IN IMS LOGGER (DFSFDLG0) LOGIC

Obtain the fix for this APAR.

APAR status

• Closed as program error.

Error description

• When scanning log records for DFSFLGE0, IMS Logger DFSFDLG0
  sends a CHKW AWE with a target that has not yet been written to
  the log buffer. Logger assumes that the buffer is full, but if a
  record comes with LL=0 because buffer is incomplete, the loop
  starts.
  Log exit processing is incorrectly called after the WADS write;
  it needs to be called before. This incorrect call order may
  cause data that is intended to be altered/removed by the exit to
  still be written to WADS and be moved to the OLDS in the event
  of a failure where OLDS is closed from WADS.
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED:                                              *
  * All IMS V15 log edit exit users                              *
  ****************************************************************
  * PROBLEM DESCRIPTION:                                         *
  * DFSFDLG0 loops between labels CKCP0813 and CKCP0818          *
  ****************************************************************
  * RECOMMENDATION:                                              *
  * INSTALL CORRECTIVE SERVICE FOR APAR/PTF                      *
  ****************************************************************
  DFSFDLC0 uses LBUSECNT to determine if all records have been
  written to the buffer.  LBUSECNT contains two halfwords, the
  total number of records in the buffer and the current number.
  DFSFDLC0 decides the buffer is full if the two halfwords are
  equal.  Because the total number is unknown until we switch
  buffers, LBUSECNT contains a total record count of zero until
  that time. This does not present a problem as long as DFSFDLC0
  does not try to process a buffer before any records are written
  to it.  That was the case in this instance, however, and the log
  edit code edits all records that DFSFDLC0 has determined exist
  in the buffer. The log edit code tried to parse the entire
  buffer into records and got into a loop when it found a zero
  length record.
  

Problem conclusion

• DFSFDLC0 has been changed to abandon the buffer when LBUSECNT is
  zero.
  

Temporary fix

• *********
  * HIPER *
  *********
  Disable the log edit routine
  

Comments

APAR Information

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

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

  UO04654

Modules/Macros

• DFSFDLC0
  

Fix information

• Fixed component name

  IMS V15

• Fixed component ID

  5635A0600

Applicable component levels

• R500 PSY UO04654

     UP25/09/03 P F509 ¢

Fix is available

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