Throttle automatic runstats

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  • Norm
    #1

    Throttle automatic runstats

    If RUNSTATS is called directly, we can specify UTIL_IMPACT_PRI ORITY to
    limit CPU consumption. For automatic runstats, there is no place to
    specify this paramater. Will it use the DBM value of UTIL_IMPACT_LIM ?


    Thanks in advance,
    Norm
    Tags: None
    • Ian
      #2
      Re: Throttle automatic runstats

      Norm wrote:
      If RUNSTATS is called directly, we can specify UTIL_IMPACT_PRI ORITY to
      limit CPU consumption. For automatic runstats, there is no place to
      specify this paramater. Will it use the DBM value of UTIL_IMPACT_LIM ?
      >
      Norm,

      With automatic stats, DB2 executes RUNSTATS in throttled mode, so it
      will respect UTIL_IMPACT_LIM .

      UTIL_IMPACT_PRI ORTY is there to assign relative priority when there
      are multiple throttled utilities executing at the same time. The
      default priority is 50. (i.e. if you just use UTIL_IMPACT_PRI ORITY
      with no value to just turn throttling on).

      Are you frequently executing mutiple utilities at the same time,
      such that you need to control their relative priorities?



        Comment

        • Norm
          #3
          Re: Throttle automatic runstats

          On May 19, 6:15 pm, Ian <ianb...@mobile audio.comwrote:
          Norm wrote:
          If RUNSTATS is called directly, we can specify UTIL_IMPACT_PRI ORITY to
          limit CPU consumption. For automatic runstats, there is no place to
          specify this paramater. Will it use the DBM value of UTIL_IMPACT_LIM ?
          >
          Norm,
          >
          With automatic stats, DB2 executes RUNSTATS in throttled mode, so it
          will respect UTIL_IMPACT_LIM .
          >
          UTIL_IMPACT_PRI ORTY is there to assign relative priority when there
          are multiple throttled utilities executing at the same time. The
          default priority is 50. (i.e. if you just use UTIL_IMPACT_PRI ORITY
          with no value to just turn throttling on).
          >
          Are you frequently executing mutiple utilities at the same time,
          such that you need to control their relative priorities?
          My misunderstandin g, I thought the
          PRIORITY = UNTHROTTLED
          in LIST UTILITIES was the current limit of CPU% a particular utility
          was allowed. I had been expecting to see the value of UTIL_IMPACT_LIM
          (50). Perhaps a "Max allowed CPU%" field would be useful.

          The CPU was at 100% and a DB2 LIST UTILITIES showed a single automatic
          runstats executing. There was a single table where SAP had done
          massive deletes during an SAP Client delete. There were only 12 rows
          left, but scattered across the tablespace. Selects against the table
          were taking hours of time as asynchronous delete cleanup was going
          on. A reorg of the table has resolved the issue.

          Thanks for responding.

            Comment

            • Pierre StJ
              #4
              Re: Throttle automatic runstats

              Here's the way this should work.
              UTIL_IMPACT_LIM IT is a dbm parm. and controlsthe total amount of
              resources one or many concurrent utilities may consume.
              UTIL_IMPACT_PRI ORITY is a utility command parm. It is enforced only if
              two or more utilities are running in the same db.
              For RUNSTATS, if the command is automated, it means DB2 will determine
              when it will run the other parms., of which UTIL_IMPACT_PRI ORITY is a
              part, can be fixed by first storing the command in the
              SYASIBM.SYSTABL ES col. for that TABNAME.
              This is done using the PROFILE option when running the RUNSTATS
              command.
              From then on, DB2 should use that priority value whenever that command
              is kaunched concurrently with anotherutility.
              Note that other utilitues should have their priority set also.
              Regards, Pierre.
              >
              >
              Norm wrote:
              If RUNSTATS is called directly, we can specify UTIL_IMPACT_PRI ORITY to
              limit CPU consumption.  For automatic runstats, there is no place to
              specify this paramater.  Will it use the DBM value of UTIL_IMPACT_LIM ?
              >
              Norm,
              >
              With automatic stats, DB2 executes RUNSTATS in throttled mode, so it
              will respect UTIL_IMPACT_LIM .
              >
              UTIL_IMPACT_PRI ORTY is there to assign relative priority when there
              are multiple throttled utilities executing at the same time.  The
              default priority is 50.  (i.e. if you just use UTIL_IMPACT_PRI ORITY
              with no value to just turn throttling on).
              >
              Are you frequently executing mutiple utilities at the same time,
              such that you need to control their relative priorities?
              >
              My misunderstandin g, I thought the
              PRIORITY = UNTHROTTLED
              in LIST UTILITIES was the current limit of CPU% a particular utility
              was allowed.  I had been expecting to see the value of UTIL_IMPACT_LIM
              (50).  Perhaps a "Max allowed CPU%" field would be useful.
              >
              The CPU was at 100% and a DB2 LIST UTILITIES showed a single automatic
              runstats executing.  There was a single table where SAP had done
              massive deletes during an SAP Client delete.  There were only 12 rows
              left, but scattered across the tablespace.  Selects against the table
              were taking hours of time as asynchronous delete cleanup was going
              on.  A reorg of the table has resolved the issue.
              >
              Thanks for responding.- Hide quoted text -
              >
              - Show quoted text -

                Comment

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