Buffer pool estimate
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Thread: Buffer pool estimate

  1. #1
    Join Date
    May 2002
    Posts
    163

    Exclamation

    Hi

    According to Oracle doc if I query

    select SIZE_FOR_ESTIMATE, BUFFERS_FOR_ESTIMATE, STD_PHYSICAL_READS
    from v$db_cache_advice
    where name='DEFAULT'
    and block_size=(select values v$parameter where name='db_block_size')
    and advice_status='ON';

    it will allow me to predict buffer pool for various cache size.

    But block_size and advice_status is not a valid column in v$db_cache_advice view. What to do????????

    2ndly If I query only

    select SIZE_FOR_ESTIMATE, BUFFERS_FOR_ESTIMATE, STD_PHYSICAL_READS
    from v$db_cache_advice
    where name='DEFAULT';

    the I am always getting value "0" for STD_PHYSICAL_READS
    columns. How to get non zero , actual , values.

    Can anybody help me.


    Thanks

    Nwcomer
    Student

  2. #2
    Join Date
    Jun 2001
    Location
    Helsinki. Finland
    Posts
    3,938
    Originally posted by newcomer

    But block_size and advice_status is not a valid column in v$db_cache_advice view. What to do????????
    Yes, they are:

    SQL> desc v$db_cache_advice
    Name
    ------------------------------------
    ID
    NAME
    BLOCK_SIZE
    ADVICE_STATUS
    SIZE_FOR_ESTIMATE
    BUFFERS_FOR_ESTIMATE
    ESTD_PHYSICAL_READ_FACTOR
    ESTD_PHYSICAL_READS

    Oracle Certified Master
    Oracle Certified Professional 6i,8i,9i,10g,11g
    email: ocp_9i@yahoo.com

  3. #3
    Join Date
    May 2002
    Posts
    163
    Hi Julian,

    u r right. It is there in Oracle 9. But why I am getting always 0 (zero) values for estd. phy reads column?

    Can u pls. tell me?

    Thanks
    Nwcomer
    Student

  4. #4
    Join Date
    Sep 2001
    Location
    NJ, USA
    Posts
    1,287
    Did u setup DB_CACHE_ADVICE = ON in init.ora file.
    Without this parameter Cache Advice process doesn't work.
    Default value for DB_CACHE_ADVICE = OFF.


  5. #5
    Join Date
    Jun 2001
    Location
    Helsinki. Finland
    Posts
    3,938
    Originally posted by newcomer
    Hi Julian,

    u r right. It is there in Oracle 9. But why I am getting always 0 (zero) values for estd. phy reads column?

    Can u pls. tell me?

    Thanks
    Well, as Shestakov said, is DB_CACHE_ADVICE set?

    Oracle Certified Master
    Oracle Certified Professional 6i,8i,9i,10g,11g
    email: ocp_9i@yahoo.com

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