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PM67558: High DBM1 pre-emptible SRB CPU for RTS system thread in DSNGERTS

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APAR status

  • Closed as unreproducible in next release.

Error description

  • High DBM1 pre-emptible SRB CPU usage can be observed in DB2 V10
(any mode), triggered by RTSTST service task (RTS) having to
process a huge number of control blocks that represent
information when a package was last used. A dump shows high
CPU usage in module DSNGERTS.

Local fix

  • Set ZPARM DISABLE_EDMRTS=YES and recycle DB2

Problem summary

  • ****************************************************************
* USERS AFFECTED: DB2 user of real time statistics for         *
*                 last used information to SYSPACKAGE          *
****************************************************************
* PROBLEM DESCRIPTION: Customer may hit high CPU usage from    *
*                      real time statistics (RTS)              *
****************************************************************
* RECOMMENDATION:                                              *
****************************************************************
DB2 maintains a list of real time statistic (RTS)
control blocks to keep track of package execution. The RTS
service task periodically externalizes the last used
information to the SYSPACKAGE table. If the table SYSPACKAGE
is accessed by another job concurrently, updating the last used
information may not be successful, as a result, the RTS control
blocks can accumulate, which could cause high CPU usage.

Problem conclusion

  • 



Temporary fix


    

  • 



Comments


    

  • DB2 has been changed to purge RTS control blocks if the total
number reach the threshold.

    



APAR Information




    

  • APAR number
    PM67558
    • 

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

  • Reported component ID
    5740XYR00
    • 

  • Reported release
    A10
    • 

  • Status
    CLOSED  UR1
    • 

  • PE
    NoPE
    • 

  • HIPER
    NoHIPER
    • 

  • Special Attention
    NoSpecatt
    • 

  • Submitted date
    2012-06-25
    • 

  • Closed date
    2012-08-03
    • 

  • Last modified date
    2012-09-05
    • 





    

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

    • 

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

    
UK80828
    

    • 



Modules/Macros


    

  • DSNGERTS

    



Fix information


    

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

  • Fixed component ID
    5740XYR00
    • 



Applicable component levels


    

  • RA10  PSY  UK80828
       UP12/08/21  P  F208
    • 



Fix is available


    

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Document Information


            

            


                        

            Modified date:
            

            05 September 2012
            

            
                      

        


        

        


      

    

  



    

  

  
    
            

          
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