Obtain the fix for this APAR.

APAR status

• Closed as program error.

Error description

• Loop in DSNB1DCM due to a loop in the PBA chain.
  The error occurs on V7 with PQ96628 applied and CLAIMDTA=YES.
  For V8, the error occurs with PQ96628 applied.
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED: All DB2 V7 users with PQ96628 applied and    *
  *                 zparm CLAIMDTA=YES.                          *
  *                                                              *
  *                 All DB2 V8 users with PQ96628 applied.       *
  ****************************************************************
  * PROBLEM DESCRIPTION: Loop in DSNB1DCM due to broken PB-PBA   *
  *                      chain.                                  *
  *                                                              *
  *                      Loop in DSNB1CLM.                       *
  *                                                              *
  *                      CREATE INDEX failure with -904 SQLCODE, *
  *                      MSGDSNT501I, and MSGDSNP016I.           *
  ****************************************************************
  * RECOMMENDATION:                                              *
  ****************************************************************
  Broken PB-PBA chain can occur due to declaim code updating the
  chain without holding a latch.  Problem only occurs when data-
  first claiming is enabled, and the release of the tablespace-
  level claim coincides with the PBA write claim count being set
  to zero.  Because of a bug in the maintenance of this count,
  the problem can only occur once in every 256 commits by a
  release(deallocate) application.
  
  The loop in DSNB1CLM is caused by the mishandling of a residual
  ROB pointer (left there by a prior cancelled drain request) in
  the tablespace-level claim/drain control words for a partitioned
  tablespace.
  
  CREATE INDEX will fail with a -904 SQLCODE if the table space
  is in some exception state (such as COPY PENDING).  This is due
  to the write claim on the index implicitly driving a write
  claim on the data.
  

Problem conclusion

• The declaim code has been modified to skip the updating of the
  PB-PBA chain when the claim being released is at the tablespace
  level for a partitioned tablespace.  Additionally, the PBA write
  claim count will no longer be decremented for the tablespace-
  level declaim.
  
  The tablespace-level claim code has been modified to correctly
  handle the residual ROB pointer.
  
  The implicit data claim on behalf of an index claim will no
  longer be performed when the claim request is coming from a
  DDL statement.
  

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:

  UK06874 UK06875

Modules/Macros

• DSNB1CLM DSNB1DCM
  

Fix information

• Fixed component name

  5740 IBM DATABA

• Fixed component ID

  5740XYR00

Applicable component levels

• R710 PSY UK06874

     UP05/09/17 P F509

• R810 PSY UK06875

     UP05/09/17 P F509

Fix is available

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Product categories:

Software

Data Management

Data Servers (Database Management Systems)

DB2 for z/OS

Software version:

710

Reference #:

PK09781

IBM Group:

Software Group

Modified date:

2005-10-03