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What does bpool_visible mean in sys.dm_os_sys_info?

Unanswered What does bpool_visible mean in sys.dm_os_sys_info?

  • Friday, June 01, 2012 3:17 AM
     
     
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    I read the BOL, and have some questions.

    1.Does it mean "Number of 8-KB buffers in the buffer pool that are directly accessible"?

    or when in non-AWE it means "Number of 8-KB buffers in the buffer pool that are directly accessible" and when in AWE it means "mapping window of AWE"?

    2.Does bpool_visible identical with "visible target memory" in this blog?
    (http://blogs.msdn.com/b/sqlprogrammability/archive/2007/01/16/9-0-memory-pressure-limits.aspx)

     

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  • Friday, June 01, 2012 4:12 AM
     
     
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    As per this article it means

    Represents the committed memory in kilobytes (KB) in the memory manager. Does not include reserved memory in the memory manager. Not nullable.



    Pradeep Adiga
    Blog: sqldbadiaries.com
    Twitter: @PradeepAdiga

     
  • Friday, June 01, 2012 4:14 AM
     
     
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    that is committed_kb.
     
  • Friday, June 01, 2012 4:34 AM
     
     
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    If you scroll down the same article, you would find the following.

    Hence in SQL Server 2012 it means bpool_visible=visible_target_kb=committed_target_kb



    Pradeep Adiga
    Blog: sqldbadiaries.com
    Twitter: @PradeepAdiga

     
  • Friday, June 01, 2012 4:35 AM
     
     
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    But in SQL server 2005/2008, it is not.
     
  • Monday, June 04, 2012 10:29 AM
     
     
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    Somebody please help me! Thanks!
     
  • Monday, June 04, 2012 10:32 AM
     
     
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    Number of 8-KB buffers in the buffer pool that are directly accessible in the process virtual address space. When not using the Address Windowing Extensions (AWE), when the buffer pool has obtained its memory target (bpool_committed = bpool_commit_target), the value ofbpool_visible equals the value of bpool_committed.

    When using AWE on a 32-bit version of SQL Server, bpool_visiblerepresents the size of the AWE mapping window used to access physical memory allocated by the buffer pool. The size of this mapping window is bound by the process address space and, therefore, the visible amount will be smaller than the committed amount, and can be further reduced by internal components consuming memory for purposes other than database pages. If the value of bpool_visible is too low, you might receive out of memory errors.