LOG_BUFFER
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Thread: LOG_BUFFER

  1. #1
    Join Date
    Sep 2000
    Location
    Chicago, IL
    Posts
    316

    Exclamation

    Can someone give me an idea of the log_buffer size ? Currently we have ours set to 163840.

    I know some of the books say that it can be >65536 for busy systems. To me even 160K seems small. Can I make it as large as 64MB - anyone sees any disadvantages to that ???

  2. #2
    Join Date
    Nov 2000
    Location
    greenwich.ct.us
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    9,092
    Check your "redo log space requests" and "redo log space wait time" from v$sysstat. If you have high counts, an increase in log_buffer will help...
    Jeff Hunter
    marist89@yahoo.com
    http://marist89.blogspot.com/
    Get Firefox!
    "I pledge to stop eating sharks fin soup and will not do so under any circumstances."

  3. #3
    Join Date
    Sep 2000
    Location
    Chicago, IL
    Posts
    316
    So is it OK to make the LOG_BUFFER 32 MB - are there any disadvantages ???

  4. #4
    Join Date
    Jun 2000
    Posts
    417
    Check out

    [url]http://www.ixora.com.au/q+a/redo.htm[/url] and
    [url]http://www.ixora.com.au/q+a/0010/17075858.htm[/url]

    For some material on the subject.

  5. #5
    Join Date
    May 2000
    Location
    ATLANTA, GA, USA
    Posts
    3,135
    32 MB Log buffer size will not be used at all.
    You may change it 2 MB or 3 MB.

  6. #6
    Join Date
    Jan 2001
    Posts
    126
    Hi,

    If you increase log buffer then redo log space requests will decrease but then the log file sync will take more time. You can check this out from v$system_event.

    You can set the log buffer to 1MB and beyond that it starts acting negatively due to larger log file sync time.

    It is better to tune log_simultaneous copies also along with log buffer size to achive good performance.

    Baliga

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