PH61323: ABEND04E RC00C200D8 IN DSNB1SWS

Obtain the fix for this APAR.

APAR status

• Closed as program error.

Error description

• ABEND04E 00C200D8 DSNB1SWS and abnormal termination due to
  a broken internal vertical deferred write queue.
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED: All Db2 12 for z/OS and Db2 13 for z/OS      *
  *                 users.                                       *
  ****************************************************************
  * PROBLEM DESCRIPTION: ABEND04E RC00C200D8 DSNB1SWS            *
  *                      when there is a shortage of available   *
  *                      buffers in the buffer pool.             *
  ****************************************************************
  * RECOMMENDATION: Apply corrective PTF when available          *
  ****************************************************************
  The ABEND04E RC00C200D8 DSNB1SWS occurred because on the
  object's chain of buffers that needed to be written out, a
  buffer for a different object was found.
  
  Buffers needed to be obtained from the LRU chain for
  a prefetch. Before using the buffer for a different object,
  logic exists to remove the buffer off the object's chain of
  buffers that need to be written out. If not enough buffers
  were obtained for the prefetch, the LRU chain needed to be
  accessed again to get the buffers. For this retry path,
  there was an error in the logic to remove the buffer off
  the chain.
  
  This problem is more likely to occur when the buffer pool
  size is very small or when the overflow portion of a
  PGSTEAL(NONE) buffer pool is heavily used.
  

Problem conclusion

• For the case when there is a shortage of available buffers
  in the buffer pool, Db2's buffer steal logic was fixed to
  ensure the buffer gets removed from the object's chain before
  using the buffer for another page.
  

Temporary fix

Comments

APAR Information

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

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

  UI97794 UI97795

Modules/Macros

• DSNB1GWB
  

Fix information

• Fixed component name

  DB2 OS/390 & Z/

• Fixed component ID

  5740XYR00

Applicable component levels

• RC10 PSY UI97794

     UP24/08/03 P F408 ¢

• RD10 PSY UI97795

     UP24/08/03 P F408 ¢

Fix is available

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