contents inside log buffer
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  1. #1
    Join Date
    Mar 2001
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    do we loss any transactions that are still resided in the log buffer? what is the actual role for log buffer?
    dino

  2. #2
    Join Date
    Oct 2000
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    Saskatoon, SK, Canada
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    At what/which stage?

    Sam
    Thanx
    Sam



    Life is a journey, not a destination!


  3. #3
    Join Date
    Mar 2001
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    29
    say... shutdown abort or system power down without notice
    dino

  4. #4
    Join Date
    Aug 2001
    Location
    Waterloo, On
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    Yes. All uncommitted transactions will be lost.

    Raminder Singh

    Oracle Certified DBA: Oracle 8i, 9i


    Mail me at raminderahluwalia@rediffmail.com.

  5. #5
    Join Date
    Dec 2001
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    Edmonton, Canada
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    Any transaction is not a complete untill the value from buffer goes into the redo log files, Once it is there into the redo log files it can'nt be lost. So there is no question of loss of data in a transaction which is still under log buffer.

  6. #6
    Join Date
    Dec 2000
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    Ljubljana, Slovenia
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    Originally posted by anujdutt
    Any transaction is not a complete untill the value from buffer goes into the redo log files, Once it is there into the redo log files it can'nt be lost. So there is no question of loss of data in a transaction which is still under log buffer.
    Not quite precise enough! Even when a change is written into a redo log file it will be lost in case of instance crash, if it has not been commited yet. In the process of instance recovery such a change will be rolled back.

    Raminder's answer was totaly exact - all uncomitted transactions will be loss in a case of instance failure, no matter if they have been written in a redo log file or not.
    Jurij Modic
    ASCII a stupid question, get a stupid ANSI
    24 hours in a day .... 24 beer in a case .... coincidence?

  7. #7
    Join Date
    Mar 2001
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    29
    then... would it be a chance that committed transactions are still left in the buffer and got an instance crash?
    dino

  8. #8
    Join Date
    Dec 2000
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    Ljubljana, Slovenia
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    No, before the transaction is commited all its changes must be written to redolog files on disk, so there is no chance of loosing any commited transaction (that is, if nothing is preventing the crash or media recovery to succeed, but that is another story).
    Jurij Modic
    ASCII a stupid question, get a stupid ANSI
    24 hours in a day .... 24 beer in a case .... coincidence?

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