PM60829: NO WARNING IMS LOG BLOCK SEQUENCE NUMBER IS WRAPPING A FULLWORD.ABENDU0616 RC8 DFSFDLS3. CANNOT /ERE, SAME ABEND IN LOG OPEN.

Obtain the fix for this APAR.

APAR status

• Closed as program error.

Error description

• Customer's system had last been cold-started many months
  ago. Many DEDB HSRE runs on this system produced a very large
  volume of log records. The IMS log stream block sequence number
  is a fullword with maximum value x'FFFFFFFF'. These are 26k
  log *blocks* not records so this is a lot of log records, but
  customer's system exceeded this value. When value wraps abend
  U0616 RC8 out of DFSFDLS3-EOVEXIT is issued. Subsequent /ERE
  will fail U0616 RC8 in log open. This is an extremely bad
  situation for the customer.
  Supporting wrapping log block sequence number is a large change
  best done on a release boundary. This apar will add support
  for warning messages as the BSN reaches large values but still
  has enough room left for customer to schedule a normal shutdown
  and cold-start at a time suitable for the business.
  Note that only a cold-start resets BSN.
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED: All IMS V11 Users                            *
  ****************************************************************
  * PROBLEM DESCRIPTION: Issue warning message for the block     *
  *                      sequence number approaching a finite    *
  *                      limit. This gives the customer time to  *
  *                      schedule a cold start to prevent an     *
  *                      abend that would only be resolved with  *
  *                      a cold start.                           *
  ****************************************************************
  * RECOMMENDATION: INSTALL CORRECTIVE SERVICE FOR APAR/PTF      *
  ****************************************************************
  When the highest block sequence number that the current OLDS
  will hold exceeds x'FFFFFFFF', IMS will take ABENDU0616, /ERE
  processing will take the same abend, and a cold start will be
  required. Previously, there was no warning message that this
  limit was approaching
  

Problem conclusion

• GEN:
  KEYWORDS:
  
  *** END IMS KEYWORDS ***
  OLDS switch processing has been changed to see if the maximum
  BSN that the current OLDS will hold exceeds a threshold and if
  it does, then msgDFS3253I will be sent. The initial threshold
  for sending the message is x'F0000000'. It is then re-issued at
  x'F1000000', again at x'F2000000', etc.
  
  The same logic is also applied to checking the OLDS at OPEN time
  during IMS start-up.
  
  The message format and description as it will appear in the
  Messages and Codes is:
  
  DFS3253I CRITICAL LIMIT APPROACHING: BSN = X'zzzzzzzz' -IMS ID-
  
  Explanation
  
  The Block Sequence Number (BSN), as used by the IMS logger, is
  approaching the finite limit of x'FFFFFFFF'. This message is
  issued as advance notice that a cold start of IMS needs to be
  done as soon as possible to avoid hitting the limit of
  x'FFFFFFFF'. Only a cold start will reset the BSN.
  
  The message is first issued when the BSN exceeds x'F0000000'.
  It is then issued again when it exceeds x'F1000000', again at
  x'F2000000', etc.
  
  If the BSN were to reach, x'FFFFFFFF', IMS would take an
  ABENDU0616, /ERE will fail with the same abend, and a cold
  start would then be required.
  
  If appropriate, this message is issued when the OLDS switch,
  and also at OLDS OPEN time during IMS start-up.
  
  The value of zzzzzzzz is the highest BSN that the current OLDS
  will contain.
  
  System action
  IMS continues processing normally.
  
  Operator action
  A normal shutdown and cold start of the IMS that produced the
  message should be scheduled as soon as possible.
  
  Note
  The BSN is different from the Log Sequence Number, which is
  an 8-byte value included in the suffix of log records.
  

Temporary fix

• *********
  * HIPER *
  *********
  

Comments

APAR Information

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

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

  PM61192 PM61194 UK77837

Modules/Macros

• DFSFDLS0 ILOG     LCDSECT
  

Fix information

• Fixed component name

  IMS V11

• Fixed component ID

  5635A0200

Applicable component levels

• R100 PSY UK77837

     UP12/04/13 P F204 Ž

Fix is available

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