Topic
5 replies Latest Post - ‏2013-09-19T08:47:20Z by 9RYQ_Kiran_mk
DF5V_krishna_Bissa
DF5V_krishna_Bissa
40 Posts
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Pinned topic Tablespace rebalancing

‏2013-09-09T17:05:09Z |

Hi all,

i wants to know whether the tablespace resize option in alter tablespace will invoke the tablespace rebalalncing in backround or the tablespace rebalance is a process that happens only when we do add container to the tablespace.To be more clear i wants to know the difference between resize and add container option with alter tablespace command.

  • 9RYQ_Kiran_mk
    9RYQ_Kiran_mk
    78 Posts
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    Re: Tablespace rebalancing

    ‏2013-09-10T13:58:23Z  in response to DF5V_krishna_Bissa

    Hi Kirishna,

    Tablespace Resize will not inovke the Rebalancing.  Add containers will add the additional container to the existing tablespace. Suppose let us consider a tablespace having 1 container of 10G when you add one more container to it. One more 10G Tablespace will be created with the same size.  Here the Tablespace Rebalance is IMPLICIT.   But, also there is an option to EXPLICITLY invoke your rebalancing option at tablespace to distribute the data equally among the two containers i.e., 5GB each, e.g., db2 alter tablespace tbspname rebalance.   

    In specific Resize option will add the additional pages or extents to the existing Tablespace containers either automatically or by DB admin manually.

    BTW, what is the version of DB2 are you using currently ?

    Best Regards,

    Kiran.M.K.

    • DF5V_krishna_Bissa
      DF5V_krishna_Bissa
      40 Posts
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      Re: Tablespace rebalancing

      ‏2013-09-11T02:53:39Z  in response to 9RYQ_Kiran_mk

      Hi Kiran,

      Thanks for details provided.i got it.one more doubt.May i know when will we opt for resize  rather than adding container to tablespace?

      Resize-when there is a requirement to add less amount of space to tablespace.

      Adding containers-when there is a requirement to add huge amount of space with out any performance loss. am i right?

      DB2 version:its on 9.5.

      2:I wants know one more  thing,what will happen if we start the online backup while the tablespace rebalancing is in progress?Will it get paused and resume once the online backup completes,or will it  get paused and resume only on the next instance recycle.

       

      Regards

      Krishna

       

      • 9RYQ_Kiran_mk
        9RYQ_Kiran_mk
        78 Posts
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        Re: Tablespace rebalancing

        ‏2013-09-11T07:29:13Z  in response to DF5V_krishna_Bissa

        Frequent resize also impacts the performance.  BTW you can define the amount of size to be resized and you can specify the growth limit upto.

        Adding containers will give better performance in terms of parallel processing.  But, after  adding the Container to an existing tablespace, the rebalancing will take  more CPU resources and obviously impacts the performance to distribute the data. 

        Also note that its recommended to reduce the HWM after REBALANCING Process.  Otherwise both will have same size of before creating the new container.

        Not sure about the functionality of the second question. I will confirm.

        Best Regards,

        Kiran.M.K.

        • DF5V_krishna_Bissa
          DF5V_krishna_Bissa
          40 Posts
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          Re: Tablespace rebalancing

          ‏2013-09-11T09:19:30Z  in response to 9RYQ_Kiran_mk

          Thanks,May i know what is recomended for adding space in large amount to the tablespaces ?resize or adding the containers. ?

          • 9RYQ_Kiran_mk
            9RYQ_Kiran_mk
            78 Posts
            ACCEPTED ANSWER

            Re: Tablespace rebalancing

            ‏2013-09-19T08:47:20Z  in response to DF5V_krishna_Bissa

            It depends on the requirement.  If you require performance benefit as well along with your current problem to be fixed for added space, then go for adding containers.

            From 9.7 onwards you can go for Adding Storage Paths additional to the current so that automatically rebalancing happens implicitly and new containers will be added. Only thing is you have to reduce the HWM.

            Best Regards,
            Kiran.M.K.