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  1. #1
    Join Date
    Sep 2006
    Location
    Columbus, OH
    Posts
    69

    Unanswered: More IOCLEANERS required?

    DB2 7.2
    AIX 5.2

    It appears to me, that the IOCLEANERS are not working effectively. I just reset the monitors and I am not getting any asynchronous writes. Here are the settigns and snapshot data. Not sure if I need to change settings or not.


    Changed pages threshold (CHNGPGS_THRESH) = 60
    Number of asynchronous page cleaners (NUM_IOCLEANERS) = 16

    Rows inserted = 6335
    Package cache inserts = 5615
    Application section inserts = 9033
    Catalog cache inserts = 0


    Bufferpool name = BP16K
    Buffer pool data logical reads = 355467
    Buffer pool data physical reads = 0
    Buffer pool data writes = 54
    Buffer pool index logical reads = 78495
    Buffer pool index physical reads = 0
    Total buffer pool read time (ms) = 0
    Total buffer pool write time (ms) = 66
    Asynchronous pool data page reads = 0
    Asynchronous pool data page writes = 0
    Buffer pool index writes = 22
    Asynchronous pool index page reads = 0
    Asynchronous pool index page writes = 0
    Total elapsed asynchronous read time = 0
    Total elapsed asynchronous write time = 0
    Asynchronous read requests = 0
    Direct reads = 0
    Direct writes = 2304
    Direct read requests = 0
    Direct write requests = 9
    Direct reads elapsed time (ms) = 0
    Direct write elapsed time (ms) = 41
    Database files closed = 0
    Data pages copied to extended storage = 0

    Thanks,
    Charlie

  2. #2
    Join Date
    May 2003
    Location
    USA
    Posts
    5,737
    At least for this bufferpool, your bufferpool hit ratio is 100% for both data and index pages. There is no synchronous I/O going on. 16 page cleaners is probably too high unless you have 16 CPU's, and even then it does not look like you need that many anyway.
    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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