Buffer Cache Ratio
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Thread: Buffer Cache Ratio

  1. #1

    Smile

    Would you agree that having a db buffer cache ratio 99%+ is not ok?

    I was reading an artical which states that the buffer cache is an invalid measure of performance and if it is above 99% then this means that there is somthing amiss? This is an area I am not clear on and have read many articals which contridic each other?

  2. #2

    Cool EXTRACT

    "Many tuning professionals and textbook authors sell advice encouraging their customers to enjoy the performance
    virtues of Oracle database buffer cache hit ratios that approach 100%. However, database buffer cache hit ratio is
    not a reliable system performance metric."

  3. #3

    buffer hit ratios.

    All your hit ratios should ideally be as close to 100 as possible. The close to 100 the healthier is your system.

    A high buffer hit ratio means that when data is requested, the information is already in memory and so reduces the number of disk reads. Since disk reads are 10,000 time slower than a memory request you can see how a high buffer hit ratio is important. It isnt the be-all-and-end-all mind but its just one of the things that needs to be healthy for a health database.

  4. #4

    Post

    Thats what I fifured but if you read the following it throws an element of confusion on the issue:

    http://www.hotsos.com/dnloads/1.Mill...CacheRatio.pdf

  5. #5
    I can't read that.


    All web sites nowadays require you to have a darn account.

    It's most annoying.

  6. #6

    Wink

    I think it is free to register for level 0 - 1 support?

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