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PM65550: PERFORMANCE ENHANCEMENT FOR UNLOAD FROM TABLE...WHEN IN DB2 V10

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APAR status

  • Closed as program error.

Error description

  • UNLOAD utility with WHEN clause consumes more CPU TIME in
DB2 v10 compared to DB2 v9.
An example of such utility would be:
UNLOAD DATA
FROM TABLE creator.tbname HEADER NONE
WHEN (column1='AA')
UNLDDN UNLFILE SHRLEVEL CHANGE ISOLATION UR
.
The number of getpages and read i/o is the same in both
runs but the code path is different.

Local fix

  • 



Problem summary


    

  • ****************************************************************
* USERS AFFECTED: All DB2 10 for z/OS utility users of the     *
*                 UNLOAD and REORG utilities                   *
****************************************************************
* PROBLEM DESCRIPTION: UNLOAD FROM TABLE WHEN encounters       *
*                       sub-optimal performance                *
****************************************************************
* RECOMMENDATION: Apply corrective PTF when available          *
****************************************************************
UNLOAD FROM TABLE WHEN runs slower than previous releases,
because the predicate evaluation was not using the
optimized path.

The same problem can occur for UNLOAD FROMCOPY FROM TABLE WHEN,
REORG DISCARD WHEN, and REORG UNLOAD EXTERNAL WHEN.

    



Problem conclusion


    

  • UNLOAD and REORG WHEN processing has been changed to use a more
optimal path to improve the performance.

    



Temporary fix


    

  • *********
* HIPER *
*********

    



Comments


    

  • ž**** PE12/09/12 FIX IN ERROR. SEE APAR PM72718  FOR DESCRIPTION

    



APAR Information




    

  • APAR number
    PM65550
    • 

  • Reported component name
    DB2 OS/390 & Z/
    • 

  • Reported component ID
    5740XYR00
    • 

  • Reported release
    A10
    • 

  • Status
    CLOSED  PER
    • 

  • PE
    NoPE
    • 

  • HIPER
    YesHIPER
    • 

  • Special Attention
    NoSpecatt
    • 

  • Submitted date
    2012-05-25
    • 

  • Closed date
    2012-07-30
    • 

  • Last modified date
    2012-10-15
    • 





    

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

    • 

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

    
UK80678
    

    • 



Modules/Macros


    

  • DSNURFBR DSNURFIT DSNURPUI DSNURSCN DSNUUGMS
DSNUULCA DSNUULJA DSNUULXA DSNUUSEL

    



Fix information


    

  • Fixed component name
    DB2 OS/390 & Z/
    • 

  • Fixed component ID
    5740XYR00
    • 



Applicable component levels


    

  • RA10  PSY  UK80678
       UP12/08/16  P  F208
    • 



Fix is available


    

  • Select the PTF appropriate for your component level.
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Document Information


            

            


                        

            Modified date:
            

            15 October 2012
            

            
                      

        


        

        


      

    

  



    

  

  
    
            

          
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