PI32491: REORG PERFORMANCE IMPROVEMENT IN LOG PHASE.

Obtain the fix for this APAR.

APAR status

• Closed as program error.

Error description

• Performance improvement during LOG phase of REORG SHRLEVEL
  CHANGE.
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED: All DB2 10 for z/OS and DB2 11 for z/OS      *
  *                 REORG TABLESPACE utility users.              *
  ****************************************************************
  * PROBLEM DESCRIPTION: REORG does not exploit full possible    *
  *                      degree of unload/reload parallelism     *
  *                      when running with DB2 Sort for z/OS     *
  *                      due to memory constraints below the     *
  *                      line indicated by DSNU397I NUMBER OF    *
  *                      TASKS CONSTRAINED BY VIRTUAL STORAGE    *
  *                      BELOW. Utility elapsed time performance *
  *                      may not be optimal in that case.        *
  ****************************************************************
  * RECOMMENDATION: Apply corrective PTF when available          *
  ****************************************************************
  REORG may not run with optimal degree of data unload/reload
  parallelism due to an expected memory constraint below the line
  when running with DB2 Sort which would be indicated by
  MSGDSNU397I.
  
  In addition, REORG is performing an unnecessary scan of dirty
  pages at the beginning of the LOG phase which can result in
  extended elapsed time.
  

Problem conclusion

• Estimation of the below the line memory consumption when
  running with DB2 Sort has been improved to allow more tasks
  to run in parallel.  REORG logic has also been modified to
  bypass the unnecessary dirty page scan at the beginning of
  the LOG phase.
  

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:

  UI25539 UI25540

Modules/Macros

•    DSNURLOG DSNURPCT
  

Fix information

• Fixed component name

  DB2 OS/390 & Z/

• Fixed component ID

  5740XYR00

Applicable component levels

• RA10 PSY UI25539

     UP15/03/17 P F503

• RB10 PSY UI25540

     UP15/03/17 P F503

Fix is available

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