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Thread: buffer cache size

  1. #1
    Join Date
    Oct 2003
    Posts
    312

    buffer cache size

    according to Oracle, buffer_cache_size= db_blocks_buffer * db_block_size.


    On my statspack report on 9i, Oracle had:

    Buffer Cache: 712M Std Block Size: 8K

    and if db_blocks_buffer is currently =0, how Oracle come up with 712m???? Please explain, and if I run the below query:

    select a.value + b.value "logical_reads",
    c.value "phys_reads",
    round(100 * ((a.value+b.value)-c.value) /
    (a.value+b.value))
    "BUFFER HIT RATIO"
    from v$sysstat a, v$sysstat b, v$sysstat c
    where
    a.statistic# = 38
    and
    b.statistic# = 39
    and
    c.statistic# = 40;


    I got -85 on my ratio which is bad.

  2. #2
    Join Date
    Sep 2002
    Location
    England
    Posts
    7,334
    well the query is wrong, also you dont post version

    if 9i is db_cache_size set?

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