Self tuning bufferpool

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  • dunleav1
    #1

    Self tuning bufferpool

    In 9.1 and 9.5 (Linux 64 bit) when a buffer pool is set to self-
    tuning, how are blocks configured in respect to blocked vs non-blocked
    when self-tuning is set to on?

    (ie) I have one bufferpool that is 16k that the IBMDEFAULTBP is shared
    between all tablespaces.
    The data tablespace has prefetch automatic set to on.


    Tags: db2 9.5 tuning
    • Ian
      #2
      Re: Self tuning bufferpool

      dunleav1 wrote:
      In 9.1 and 9.5 (Linux 64 bit) when a buffer pool is set to self-
      tuning, how are blocks configured in respect to blocked vs non-blocked
      when self-tuning is set to on?
      >
      (ie) I have one bufferpool that is 16k that the IBMDEFAULTBP is shared
      between all tablespaces.
      The data tablespace has prefetch automatic set to on.
      STMM will not tune the size of the block-based area of a bufferpool.



        Comment

        • dunleav1
          #3
          Re: Self tuning bufferpool

          On Sep 26, 3:15 pm, Ian <ianb...@mobile audio.comwrote:
          dunleav1 wrote:
          In 9.1 and 9.5 (Linux 64 bit) when a buffer pool is set to self-
          tuning, how are blocks configured in respect to blocked vs non-blocked
          when self-tuning is set to on?
          >
          (ie) I have one bufferpool that is 16k that the IBMDEFAULTBP is shared
          between all tablespaces.
          The data tablespace has prefetch automatic set to on.
          >
          STMM will not tune the size of the block-based area of a bufferpool.
          I can't seem to set a block based area in a bufferpool that is self
          tuning.
          I can't set a large initial size for the bufferpool area either. When
          I set a size and recycle the database, the
          initial size defaults back to 1000 16k when using self tuning.

          Isn't it possible to allocate a larger initial bufferpool area, and to
          use block-based bufferpools when using self tuning memory?

            Comment

            • Ian
              #4
              Re: Self tuning bufferpool

              dunleav1 wrote:
              I can't seem to set a block based area in a bufferpool that is self
              tuning.
              create bufferpool bp
              size 100000 automatic
              numblockpages 1000
              pagesize 4096
              I can't set a large initial size for the bufferpool area either. When
              I set a size and recycle the database, the
              initial size defaults back to 1000 16k when using self tuning.
              alter bufferpool yourbp size 100000 automatic numblockpages 1000


              Keep in mind, DB2 may reduce the size of the bufferpool if it doesn't
              see demand for it.


              Isn't it possible to allocate a larger initial bufferpool area, and to
              use block-based bufferpools when using self tuning memory?
              Yes. But as I said, the number of block pages is fixed when the
              bufferpool is allocated. So, while STMM may grow (and shrink) the
              size of the page-based area of the bufferpool, the block-based
              area will remain fixed.


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