PI76386: ABEND04E RC00C90101 DSNKINSL ERQUAL5004

Obtain the fix for this APAR.

APAR status

• Closed as program error.

Error description

• ABEND04E RC00C90101 DSNKINSL ERQUAL5004 using data sharing.
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED: DB2 for z/OS V11 data sharing users,         *
  *                 utilizing duplexed group buffer pools.       *
  ****************************************************************
  * PROBLEM DESCRIPTION: Lost updates in data sharing.           *
  *                                                              *
  *                      Corrupted data can result in any of     *
  *                      the following symptoms:                 *
  *                       - Incorrect output, INCORROUT.         *
  *                       - ABEND04E RC00C90101, RC00C90102,     *
  *                         RC00C90105, or RC00C902xx in         *
  *                         various CSECTs.                      *
  *                       - Data/index inconsistencies reported  *
  *                         by the CHECK INDEX utility.          *
  *                       - Page regression reported by the      *
  *                         DSN1LOGP utility.                    *
  ****************************************************************
  * RECOMMENDATION:                                              *
  ****************************************************************
  In DB2 V11, DB2 may to choose to write updated pages directly to
  DASD rather than going through the group buffer pool (referred
  to as "GBP write-around").  This can only happen if the pages
  are not present in the GBP, and no other member has a registered
  interest.
  
  For the case where the GBP is duplexed, there are unusual cases
  where an "orphan" updated page can reside in the secondary
  structure, but not in the primary.  If the write-around logic
  suppresses the write to the primary and goes directly to DASD,
  the orphan page in the secondary - now down-level - may reappear
  if the GBP drops out of duplexing and switches over to the
  secondary structure, before the "garbage collection" process
  has had a chance to detect and delete the orphan page.
  
  The appearance of the down-level page can result in various
  "broken data" symptoms.
  

Problem conclusion

• For the case where GBP write-around is being performed for
  a duplexed structure, DB2 will now request a delete of the
  affected pages from the secondary structure in parallel with
  the DASD writes.  For workloads where write-around is being
  performed frequently, a noticable increase may be seen in
  the "secondary delete_namelist" statistics counter QBGL2D.
  

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:

  PI76387 UI47329

Modules/Macros

• DSNB5CMX
  

Fix information

• Fixed component name

  DB2 OS/390 & Z/

• Fixed component ID

  5740XYR00

Applicable component levels

• RB10 PSY UI47329

     UP17/06/02 P F706 Ž

Fix is available

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