Post reply

Log backup

  • July 6, 2011 at 3:44 am

    #253220

    Hi,

    Please let me know my log backup contains only committed transaction or both committed and uncommitted tran in it.

  • July 6, 2011 at 4:05 am

    #1348819

    The below link shows how log backups are used , and should help you understand what happens to the transaction in the log backups

    http://msdn.microsoft.com/en-us/library/ms190440.aspx

    in particular the section

    How Are Log Backups Used?

    Jayanth Kurup[/url]

  • July 6, 2011 at 4:09 am

    #1348821

    This link from Paul Randal should be enough to clear your doubts.

    http://technet.microsoft.com/en-us/magazine/2009.02.logging.aspx

    M&M

  • July 6, 2011 at 4:09 am

    #1348822

    does log back up contains bot committed and committed tran???

  • July 6, 2011 at 5:19 am

    #1348837

    shilpa.shankar87 (7/6/2011)

    does log back up contains bot committed and committed tran???

    Can you tell me if you read the link I shared. I am sure you didn't and I am not going to answer this question if you haven't read it.

    As this is a basic question, it would be nicer to understand the internals than just asking "Give me answer to my question".

    If you didn't understand what's written in the link, then you may post here again.

    M&M

  • July 6, 2011 at 6:07 am

    #1348860

    [font="Times New Roman"]

    Hi,

    You might be aware that all modications made to data are recorded in the transaction log file for recovery purpose. Log back up copy these modifications from the transaction log file into back up file.

    These modications might have done either by commited or uncommited transaction. Once back up is complete all the modications made by commited transactions are truncated from the transaction log file.

    Let me know if you have any concern.

    Best Regards,

    Anil

    [/font]

  • July 6, 2011 at 7:00 am

    #1348901

    anil_kumar32 (7/6/2011)

    Once back up is complete all the modications made by commited transactions are truncated from the transaction log file.

    Not necessarily. There are a number of things that can keep log records active even after the transaction has committed and the log backup has run.

    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

  • July 6, 2011 at 1:03 pm

    #1349244

    I think the OP is really looking for an answer as to what happen during the application of the log backup during recovery i.e what gets rolled forward vs what gets rolled back.

    Jayanth Kurup[/url]

  • July 6, 2011 at 9:57 pm

    #1349412

    [font="Times New Roman"]

    As far as my knowledge is concerned, it happens in that way. Please come forward and add few valuable and concrete facts.

    Regards,

    Anil

    [/font]

  • July 7, 2011 at 3:05 am

    #1349497

    GilaMonster (7/6/2011)

    anil_kumar32 (7/6/2011)

    Once back up is complete all the modications made by commited transactions are truncated from the transaction log file.

    Not necessarily. There are a number of things that can keep log records active even after the transaction has committed and the log backup has run.

    Would Ghost records fall under the above category ?

    Jayanth Kurup[/url]

  • July 7, 2011 at 3:19 am

    #1349502

    No.

    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

  • July 7, 2011 at 3:23 am

    #1349507

    [font="Times New Roman"]

    Thnx Gail:-)

    [/font]

Viewing 12 posts - 1 through 11 (of 11 total)

You must be logged in to reply to this topic. Login to reply