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  1. #1
    Join Date
    Feb 2009
    Posts
    1

    Unanswered: Poor Performance with 4 DB's in one Instance

    Hello,
    We are facing some performance issues while running multiple databases in a single IDS Instance.
    We have just observed that when we run only one DB in one instance, the performance remains much better. Where as while running multiple databases in one instance results in very poor performance and we are getting issues like transaction time out.
    I want to ask, whether there are any onconfig parameters to improve the performance while running multiple database in one IDS instance. I would also like to know about any other tips and recommendations to handle such scenarios.
    Our system is a pure OLTP system and there are 24 instances running on it.

    The machine which we are using is.

    SunOS 5.10 Generic_125100-09 sun4v sparc SUNW,Sun-Fire-T200.
    with 32GB RAM

    The configuration file , outputs of onstat -m and onstat -p, onstat -g seg ,onstat -F are attached.

    Thanks n Regards,
    Anees Ahmad
    Attached Files Attached Files
    Last edited by aanees; 02-06-09 at 11:28.

  2. #2
    Join Date
    Mar 2006
    Posts
    15
    Is it actualy yet?
    Please give onstat -g dis.

  3. #3
    Join Date
    Feb 2009
    Posts
    51
    Hi, aanees.

    Try to increase next parameters
    SHMVIRTSIZE 655360
    and
    BUFFERPOOL size=2K,buffers=300000,lrus=23,lru_min_dirty=50.000000,lru_max_dirty=60. 000000

  4. #4
    Join Date
    Jun 2005
    Location
    Santa Fe, Argentina
    Posts
    27
    Hi, the OLTP environment need some special tunning, specially need very short checkpoints. onstat -F show only CHUNK WRITES, I suggest to balance them with LRU writes reducing LRU_MIN_DIRTY and LRU_MAX_DIRTY from 50,60 to 10,20 and check with onstat -F. The PHYSFILE seems to be to short, increase it to avoid checkpoint for 75% of physfile full. Add more TEMPDBSPACES, spread them in differentes disk systems. Reset the statistics (onstat -z) before high usage, then check (onstat -p) for wait values.

  5. #5
    Join Date
    Jun 2005
    Location
    Santa Fe, Argentina
    Posts
    27
    At version 10, the checkpoint are "blocking checkpoint", all the database operation is suspended, version 11.5 implement "non blocking checkpoint" and other important performance enhancements, I suggest if you can, go to 11.5 version (cheetah), it is realy faster.

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