database hangs on free buffer waits
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Thread: database hangs on free buffer waits

  1. #1
    Join Date
    Dec 1999
    Location
    Tel-Aviv, Israel
    Posts
    12

    database hangs on free buffer waits

    hi all.
    i'm experiencing major performance problems on my application.
    i have 2 db's on the same HP-UX machine, each one has an SGA of
    about 2.3GB, the machine has 6 CPUs and 6GB ram.
    oracle version - 8.1.7.4 64bit.

    i have a very insert-intensive application (about 2000 rows/s).
    my redo logs & rbs are placed on raw partitions, the rest of the
    db files are on vxfs fs.

    after i start the application, the load on the database is huge,
    but no stress in the storage machine (Va7400) nor the host's cpu.
    after about 10-15 minutes, i start recieveing "free buffer waits"
    on my application threads, and basically, it hangs forever.

    had anyone ever encountered these waits?
    please share your experience.
    regards,
    ido

  2. #2
    Join Date
    Dec 1999
    Location
    Tel-Aviv, Israel
    Posts
    12
    of course, main parameters:

    db_block_size=8192
    db_block_buffers=256000
    db_file_multiblock_read_count=32
    db_block_max_dirty_target=4000
    db_writer_processes=10
    db_block_lru_latches=10

  3. #3
    Join Date
    Jan 2003
    Posts
    78
    Are you sure you have 256000 database buffers? I think there is typo.
    With 256000 buffers, and block size of 8K, your database buffer size will be very very big.
    HTH.
    Shripad Godbole
    OCP DBA (8,8i,9i)

    "Let's document it and call it a feature."

  4. #4
    Join Date
    Dec 1999
    Location
    Tel-Aviv, Israel
    Posts
    12
    hi.
    no, no error at all.
    both databases buffer cache are the size of 2GB.
    i know it's large, but the application is REALLY write-intensive.

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