Redo log Questions
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Thread: Redo log Questions

  1. #1
    Join Date
    Feb 2001
    Location
    Kolkata- India
    Posts
    356

    Talking

    Guys,
    I have lot of questions regarding redo buffer. Here I shoot
    1) Does redo logs record uncomitted data?
    2) Does log writes from log_buffer when a commit happens?
    3) how and when is redo_buffer populated?

    Regards

  2. #2
    Join Date
    Sep 2000
    Posts
    19


    1. Yes, redo log buffer is used only for that purpose. It helps you to recover the uncommited transaction on a database crash/ failure.

    2. If it is archive log mode then the content of the redo log buffer are moved to redo log files on the following occations

    1. Before a database flush a log flush takes place
    2. Commit.
    3. Time out
    4. Ckpt occurs.

    3. when ever a content of the database are changed or a new data is created .

  3. #3
    Join Date
    Feb 2001
    Location
    Kolkata- India
    Posts
    356

    Question

    IF REdo logs record uncomitted data.
    No suppose a database is recovered to a point in time. When the user logs in now, will he be able to se uncomitted data?

  4. #4
    Join Date
    Feb 2001
    Posts
    125

    Uncommited data

    [QUOTE][i]Originally posted by sudip [/i]
    [B]IF REdo logs record uncomitted data.
    No suppose a database is recovered to a point in time. When the user logs in now, will he be able to se uncomitted data? [/B][/QUOTE]

    No user can't see the uncommited data because
    After recovery ( Rolling Forward) uncommited data are
    removed by transaction recovery

  5. #5
    Join Date
    Feb 2001
    Location
    Kolkata- India
    Posts
    356

    Smile

    Thanks a lot for the answer.

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