Contention for Space in the Redo Log Buffer
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Thread: Contention for Space in the Redo Log Buffer

  1. #1
    Join Date
    Sep 2000
    Posts
    362
    I ran this query on the database and got a result of 77.44 %. I know that it should be less than 1%. what do I need to fix this problem.

    /***Detecting Contention for Space in the Redo Log Buffer**/


    select round(greatest(
    2 (sum(decode(ln.name, 'redo copy', misses,0))
    3 / greatest(sum(decode(ln.name, 'redo copy', gets,0)),1)),
    4 (sum(decode(ln.name, 'redo allocation', misses,0))
    5 / greatest(sum(decode(ln.name, 'redo allocation', gets,0)),1)),
    6 (sum(decode(ln.name, 'redo copy', immediate_misses,0))
    7 / greatest(sum(decode(ln.name, 'redo copy', immediate_gets,0))
    8 + sum(decode(ln.name, 'redo copy', immediate_misses,0)),1)),
    9 (sum(decode(ln.name, 'redo allocation', immediate_misses,0))
    10 / greatest(sum(decode(ln.name, 'redo allocation', immediate_gets,0))
    11 + sum(decode(ln.name, 'redo allocation', immediate_misses,0)),1)))
    12 * 100,2)"Percentage "
    13 from v$latch l, v$latchname ln
    14 where l.latch# = ln.latch#;


    Percentage -----------
    77.44



  2. #2
    Join Date
    Jan 2001
    Posts
    126
    Hi,

    Increase the redo copy latches based on the number of CPUs you have. Also look at the redo space requests Vs redo writes & logfile sync time and tune the log buffer size.

    Baliga

  3. #3
    Join Date
    Feb 2000
    Location
    Washington DC
    Posts
    1,843
    See the size of current redologs is enough. If not try creating/adding couple of more logs or resizing current logs
    Reddy,Sam

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