redo log buffer sizing
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Thread: redo log buffer sizing

  1. #1
    In Oracle Education course - 9i - they say LGWR is writting to disk the redo entries in 5 situations, and 2 of them are:
    - 1/3 of log buffer is full;
    - there are more than 1 Mb of redo entries in redo log buffer cache.
    So, I'm thinking: if it is writting to disk if 1Mb entries exists and is no reason for 1/3 to be larger than 1Mb, then I should never give to LOG_BUFFER more than, let's say, oversizing a bit, 4Mb of memory. 4Mb of RAM is very little, so the sizing of redo log buffer is very simple: there is no reason to be more than 4Mb, (in fact 3Mb), then I'll give'm 4Mb and end of story.

    Is this thinking correct?
    ovidius over!

  2. #2
    Join Date
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    Yes, it's correct. There is very seldom need of even making LOG_BUFFER > 1M.

    Oracle Certified Master
    Oracle Certified Professional 6i,8i,9i,10g,11g,12c
    email: ocp_9i@yahoo.com

  3. #3
    THNX, Julian.
    My logic was to free-up of one sizing/headache, as long as 3Mb is very little. So, I'll give him 3Mb and let him (redo log buffer cache) cry to another door...
    ovidius over!

  4. #4
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    No need IMHO for 3M. 1M should be more than enough.

    Oracle Certified Master
    Oracle Certified Professional 6i,8i,9i,10g,11g,12c
    email: ocp_9i@yahoo.com

  5. #5
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    And just to make things clear: This is not something new to 9i, it has been so for a long time. So it is also valid for all releases of 8i, not just for 9i.
    Jurij Modic
    ASCII a stupid question, get a stupid ANSI
    24 hours in a day .... 24 beer in a case .... coincidence?

  6. #6
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    Oracle recommend NOT increasing the LOG_BUFFER > 1MB, as there is no significant benifit in doing so.

    Cheers
    OCP 8i, 9i DBA
    Brisbane Australia

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