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  1. #1
    Join Date
    Jul 2006
    Location
    Pune , India
    Posts
    433

    Unanswered: Page cleaners Tuning

    we are having some 4 hrs constant load performance tests going on where the final readings comes some what like these

    db2 9.1.3
    windows
    ------------

    Buffer pool data writes = 21341
    Asynchronous pool data page writes = 15711
    Buffer pool index writes = 5134841
    Asynchronous pool index page writes = 152345

    LSN Gap cleaner triggers = 10899
    Dirty page steal cleaner triggers = 574
    Dirty page threshold cleaner triggers = 99589

    -------------

    sum of all Bufferpool ~ 2GB
    softmax 1000
    logfilsz 12000
    CHNGPGS_THRESH 25
    NUM_IOCLEANERS AUTOMATIC
    -------------


    even though the % steal is quite low but isn't in our case the page cleaners
    are getting fired too aggresively.
    can someone please recommend some better cfg

    regards
    Rahul
    Rahul Singh
    Certified DB2 9 DBA / Application Developer

  2. #2
    Join Date
    Jan 2008
    Posts
    88
    increase ur CHNGPGS_THRESH in increment of 5 and test..may be 30-40 would be a good range

  3. #3
    Join Date
    Jul 2006
    Location
    Pune , India
    Posts
    433
    thanks,
    but dont you think synch write is happening too often than asynch writes.
    i am really bothered because of that. wont delaying cleaning would increase it further ?
    Rahul Singh
    Certified DB2 9 DBA / Application Developer

  4. #4
    Join Date
    Jan 2008
    Posts
    88
    check how many page cleaners are active at a time, so u would get an idea..then if u see more steal cleaner triggers..try to increase it...its just a thought..test it thoroughly...

  5. #5
    Join Date
    Jan 2008
    Posts
    45
    Set DB2_USE_ALTERNATE_PAGE_CLEANING registry variable on..That will help you

  6. #6
    Join Date
    May 2003
    Location
    USA
    Posts
    5,737
    Quote Originally Posted by db2rocks
    Set DB2_USE_ALTERNATE_PAGE_CLEANING registry variable on..That will help you
    This will cause the page cleaners to fire more agressively.

    Regarding the original post, I think you are worrying about a problem that does not exist.
    M. A. Feldman
    IBM Certified DBA on DB2 for Linux, UNIX, and Windows
    IBM Certified DBA on DB2 for z/OS and OS/390

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