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  • January 12, 2014 at 11:53 am

    #396093

    Hi,

    please let me know what are the transaction undo files means.

    Thanks.

  • January 12, 2014 at 1:01 pm

    #1679468

    There's no such thing as a transaction undo file in SQL Server. That not an oracle term?

    There are standby files in log shipping which store information relating to undo operations.

    Gail Shaw
    Microsoft Certified Master: SQL Server, MVP, M.Sc (Comp Sci)
    SQL In The Wild: Discussions on DB performance with occasional diversions into recoverability

    We walk in the dark places no others will enter
    We stand on the bridge and no one may pass

  • January 12, 2014 at 11:13 pm

    #1679492

    Hi,

    When restoring transaction log with the “STAND BY” option, SQL Server will go over the transaction log and save all uncommitted transactions to a file with .tuf(Transaction UNDO File) extension.

    The tuf file will be used when you restore the next transaction log file. First, the SQL Server will REDO all the uncommitted transactions that are in the tuf file and then continue to restore the next transaction log.The tuf file will contain the uncommitted transactions not just from the latest transaction log but uncommitted transactions in all previous transaction logs that have been restored.

    So with the above explanation let us assume a rebuild index on a big table that has run for 45 mins and let’s say 3 log backups were taken in this duration, so first log backup uncommitted transactions will be written to tuf file while restoration and when the second log backup is being restored, the sql server will redo all the uncommitted transactions from the tuf file and will continue the restoring the log backup but the second log backup also has uncommitted transactions so SQL server will again UNDO the index operation and will save the uncommitted transactions to tuf file and this process continues until transaction is committed in further log backups causing the delay in LOG RESTORE…

  • January 13, 2014 at 5:15 pm

    #1679760

    Now there's an "oolie". Thanks for the post.

    --Jeff Moden

    RBAR is pronounced "ree-bar" and is a "Modenism" for Row-By-Agonizing-Row.
    First step towards the paradigm shift of writing Set Based code:
    ________Stop thinking about what you want to do to a ROW... think, instead, of what you want to do to a COLUMN.

    Change is inevitable... Change for the better is not.

    Helpful Links:
    How to post code problems
    How to Post Performance Problems
    Create a Tally Function (fnTally)

  • February 8, 2014 at 6:51 am

    #1687315

    Thank you

    So it exists in standby mode only. I heard by deleting the .tuf file logshipping will fail. i.e. in which place we can find .tuf file

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