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PI62582: QUERY REFERS XML COLUMNS USING XML INDEXES HAS VERY HIGH GETPAGE AND BAD PERFORMANCE.

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APAR status

  • Closed as program error.

Error description

  • Query refers XML columns fully scans DOCID index due to wrong
best matching predicate used by DB2.

Local fix

  • 



Problem summary


    

  • ****************************************************************
* USERS AFFECTED:                                              *
* All DB2 for z/OS users of XML                                *
****************************************************************
* PROBLEM DESCRIPTION:                                         *
* A performance issue of excessive                             *
* getpage during XML DOCID index access.                       *
****************************************************************
* RECOMMENDATION:                                              *
* Apply corrective PTF when available.                         *
****************************************************************
If XML value index was used to access table with XML column, at
the stage of DOCID index scan process to gather rid list of
qualifying base row, index look aside was not enabled.
Therefore, performance degradation occurred during the process.

    



Problem conclusion


    

  • DB2 code has been modified to enable index look-aside for XML
DOCID index access.

    



Temporary fix


    

  • *********
* HIPER *
*********

    



Comments


    

  • 



APAR Information




    

  • APAR number
    PI62582
    • 

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

  • Reported component ID
    5740XYR00
    • 

  • Reported release
    A10
    • 

  • Status
    CLOSED  PER
    • 

  • PE
    NoPE
    • 

  • HIPER
    YesHIPER
    • 

  • Special Attention
    NoSpecatt / Xsystem
    • 

  • Submitted date
    2016-05-16
    • 

  • Closed date
    2017-09-05
    • 

  • Last modified date
    2017-10-02
    • 





    

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

    • 

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

    
UI50078 UI50079 UI50080
    

    • 



Modules/Macros


    

  • DSNIXLDI DSNIXLDR

    



Fix information


    

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

  • Fixed component ID
    5740XYR00
    • 



Applicable component levels


    

  • RC10  PSY  UI50078
       UP17/09/19  P  F709  ¢
    • 

  • RB10  PSY  UI50080
       UP17/09/20  P  F709  ¢
    • 

  • RA10  PSY  UI50079
       UP17/09/20  P  F709  ¢
    • 



Fix is available


    

  • Select the PTF appropriate for your component level.
You will be required to sign in. Distribution on physical
media is not available in all countries.
    








      
              
                            

              

              [{"Business Unit":{"code":"BU059","label":"IBM Software w\/o TPS"},"Product":{"code":"SSEPEK","label":"Db2 for z\/OS"},"Component":"","ARM Category":[],"Platform":[{"code":"PF025","label":"Platform Independent"}],"Version":"10.1","Edition":"","Line of Business":{"code":"LOB10","label":"Data and AI"}},{"Business Unit":{"code":"BU054","label":"Systems w\/TPS"},"Product":{"code":"SG19M","label":"APARs - z\/OS environment"},"Component":"","ARM Category":[],"Platform":[{"code":"PF025","label":"Platform Independent"}],"Version":"10.1","Edition":"","Line of Business":{"code":"","label":""}}]
              

                          

          
 
        

      

    

      

        

          

            
Document Information


            

            


                        

            Modified date:
            

            02 October 2017
            

            
                      

        


        

        


      

    

  



    

  

  
    
            

          
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