PH08835: ABEND04E RC00C90101 DSNICMT2 ERQUAL5000

Obtain the fix for this APAR.

APAR status

• Closed as program error.

Error description

• During a Data Manager commit, DSNICMT2 was going down a process
  to delete all PBA0 blocks associated with a page set (table
  space). However a block for the second PBA0 was freed already.
  This resulted in an abend with the following title:
                                                                 .
  DSN ,ABND=04E-00C90101,U=xxxxxxx ,M=N  ,C=111.DMC
  -DSNICMT2,M=DSNTFRCV,LOC=DSNIDM  .DSNICMT2:5000
                                                                 .
  (In this case erqual5000 is the same as erqual535B , for
   eyecatcher not matching ie freed block here).
  It looks like there was parallelism involved.
                                                                 .
  Additional keywords: Parallel task involved.
                       erqual5000 eyecatcher 'PARR' missing as
                       block free freed.
  

Local fix

• Rebind with DEGREE = 1
  

Problem summary

• ****************************************************************
  * USERS AFFECTED: Db2 11 for z/OS and Db2 12 for z/OS users    *
  *                 of indexes on partitioned table spaces       *
  *                 using CPU parallelism.                       *
  ****************************************************************
  * PROBLEM DESCRIPTION: When CPU parallelism is used, SQL       *
  *                      query running on a partitioned table    *
  *                      space using index access can cause      *
  *                      ABEND DSNICMT2:5000 at thread commit    *
  *                      time.                                   *
  ****************************************************************
  * RECOMMENDATION: Apply corrective PTF when available.         *
  ****************************************************************
  During thread commit, Db2 needs to delete all the partition
  level agent pageset blocks(PBA0) associated with a partitioned
  table space.   However a PBA0 block has already been freed
  resulting in abend DSNICMT2:5000.
  
  When CPU parallelism is used, SQL query running on a partitioned
  table space using index access needs to read the PBA0 in order
  to determine if a cross partition update has happened on a data
  partition.  If the PBA0 for a partition hasn't been created by
  the parent thread,  the child thread accessing this block will
  cause it to be allocated in the child thread storage pool.
  
  The storage for the PBA0 will get freed when the child agent
  goes through deallocation.  At commit time when the parent
  thread tries to free the storage that has already been freed,
  DSNICMT2:5000 abend is issued.
  

Problem conclusion

• Db2 code has been modified to avoid creating a Pba0 block
  using the child thread storage pool when running SQL query
  on a partitioned table space using index access and CPU
  parallelism.
  

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:

  UI66013 UI66014

Modules/Macros

•    DSNIONX2 DSNIOST2 DSNIRIDL DSNISFX2 DSNIXLDI
  DSNKFLRR DSNKFLST DSNKFPRV DSNKFTCH DSNKFTRR DSNKNXT2 DSNOLDEL
  

Fix information

• Fixed component name

  DB2 OS/390 & Z/

• Fixed component ID

  5740XYR00

Applicable component levels

• RB10 PSY UI66014

     UP19/10/30 P F910

• RC10 PSY UI66013

     UP19/10/30 P F910

Fix is available

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