none
Cleaner Memory KB Perfmon Counter is Wacky RRS feed

  • Question

  • Normally we see that the Analysis Services "Cleaner Memory KB" (and "Cleaner Memory shrinkable KB") is lower than the "Memory Usage KB".

    However on some days "Cleaner Memory KB" can increase higher than "Memory Usage KB" by several GB.  Our server has 32 GB of RAM.

    Can anyone explain what kind of memory would be included in the counter "Cleaner Memory KB" that would not be included in "Memory Usage KB"?  Is this a bug and/or a source of possible problems with SSAS?

    Thanks in advance,
    David


    David Beavon
    Wednesday, March 3, 2010 4:00 AM

Answers

  • Hi Daivid,
    The statement "Notice that the Cleaner Memory KB counter increases faster than the Private Bytes counter. This occurs because SQL Server 2005 Analysis Services cleans the cache, even though the server is not under memory pressure. " is by design instead of a bug.
    So you may observe that the Cleaner Memory KB is larger than Memory Usage but usually should not be very larger, otherwise you may encounter a performance issue.

    In your scenario, it looks that your Cleaner Memory KB is very larger than Memory Usage. Did you encounter a performance issue at your side? If so, I recommend that you issue a ticket to Customer Support Services (CSS) via phone for more professional and in-depth trouble-shooting.

    To obtain the phone numbers for specific technology request please take a look at the web site listed below.
    http://support.microsoft.com/default.aspx?scid=fh;EN-US;PHONENUMBERS

    If you are outside the US please see http://support.microsoft.com for regional support phone numbers.

    Best regards,
    Charles Wang


    Please remember to mark the replies as answers if they help and unmark them if they provide no help
    Tuesday, March 9, 2010 10:03 AM
    Moderator

All replies

  • Hi David,
    The counter "Cleaner Memory KB" is the total of "Cleaner Memory nonshrinkable KB" and "Cleaner Memory shrinkable KB". You can find their detailed description in the SSAS2005 Performance Guide white paper, http://www.microsoft.com/technet/prodtechnol/sql/2005/ssas2005perfguide.mspx.

    MSAS 2005:Memory\Cleaner Memory nonshrinkable KB

    Displays the amount of memory, in KB, non subject to purging by the background cleaner.

    MSAS 2005:Memory\Cleaner Memory shrinkable KB

    Displays the amount of memory, in KB, subject to purging by the background cleaner.

    MSAS 2005:Memory\Cleaner Memory KB

    Displays the amount of memory, in KB, known to the background cleaner.  (Cleaner memory shrinkable + Cleaner memory non-shrinkable.)  Note that this counter is calculated from internal accounting information so there may be some small deviation from the memory reported by the operating system.




    It may be possible that the counter value is larger than the "memory usage kb". From this article, http://support.microsoft.com/kb/936262, we can find the following description:
    -----------------------------------------
    Notice that the Cleaner Memory KB counter increases faster than the Private Bytes counter. This occurs because SQL Server 2005 Analysis Services cleans the cache, even though the server is not under memory pressure.
    -----------------------------------------

    The Private Bytes counter is same as Memory Usage. So this is by design instead of a problem with SSAS.


    Best regards,
    Charles Wang
    Please remember to mark the replies as answers if they help and unmark them if they provide no help
    Friday, March 5, 2010 7:52 AM
    Moderator
  • I'm still confused.  In the KB article you referenced, the bug that was described is very close to what I am still seeing in the product. 

    In the KB article, the note you pointed out (that the "Cleaner Memory KB" was above "Private Bytes") was a symptom of that bug, right?  Why am I experiencing it now on the most recent CU if the bug was supposedly fixed already?

    As in the bug from the KB article, I am worried that the faulty "Cleaner Memory KB" will lead to memory being cleaned up too early - or that it may even cause SSAS going into a panic mode for reclaiming memory even though there is no shortage of it.


    Thanks David
    David Beavon
    Monday, March 8, 2010 4:24 PM
  • Hi Daivid,
    The statement "Notice that the Cleaner Memory KB counter increases faster than the Private Bytes counter. This occurs because SQL Server 2005 Analysis Services cleans the cache, even though the server is not under memory pressure. " is by design instead of a bug.
    So you may observe that the Cleaner Memory KB is larger than Memory Usage but usually should not be very larger, otherwise you may encounter a performance issue.

    In your scenario, it looks that your Cleaner Memory KB is very larger than Memory Usage. Did you encounter a performance issue at your side? If so, I recommend that you issue a ticket to Customer Support Services (CSS) via phone for more professional and in-depth trouble-shooting.

    To obtain the phone numbers for specific technology request please take a look at the web site listed below.
    http://support.microsoft.com/default.aspx?scid=fh;EN-US;PHONENUMBERS

    If you are outside the US please see http://support.microsoft.com for regional support phone numbers.

    Best regards,
    Charles Wang


    Please remember to mark the replies as answers if they help and unmark them if they provide no help
    Tuesday, March 9, 2010 10:03 AM
    Moderator