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  1. #1
    Join Date
    Feb 2003
    Posts
    23

    Thumbs up Unanswered: REDO Allocations

    Dear Readers,

    1 ) Can anyone explain the concepts of redo copy and redo allocation.
    2 ) Where is the SCN # located in the control file and can we view this after the command alter database backup controlfile to trace.


    Thanks And regards
    MANI PS

  2. #2
    Join Date
    Apr 2003
    Location
    Minneapolis, MN
    Posts
    273

    Re: REDO Allocations

    Dear Manisiva,

    These two are latches. When Server Process needs to transfer data buffers into log buffers. It gets redo copy latche. After getting this latche, it tries to get redo allocation latche. When It get that, It can transfer the blocks into log bufers. After completion of transformation, it releases the redo allocation latche. After releasing the redo allocation latche, It can release the redo copy latche.

    There is only one redo allocation lache per Instance per Database.
    There is one redo copy latche per Server Process.

    Thanks..

    Hings.

    =====

    Still Learning...

  3. #3
    Join Date
    Apr 2002
    Location
    California, USA
    Posts
    482

    Thumbs up

    On your question #2:

    You don't have to dump the control file to find the current SCN. Use the following query to find it:

    select max(ktuxescnw * power(2, 32) + ktuxescnb) from x$ktuxe;


    Hope that helps,

    clio_usa
    OCP - DBA
    Visit our Web Site

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