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  1. #1
    Join Date
    Jan 2002
    Posts
    148

    Interpret change_vector$$ column

    Hello,

    How would i interpret Change_Vector$$ Column
    of MLOG$_ log table on Master Table ?

    Update TAB1 Set COL1='xyz' ;

    The above update statement will poulate the Logtable
    with following values

    COLUMN
    UPDATED VALUE
    ---- -----
    Col1 02
    col2 04
    col3 08
    col4 10

    col5 20
    col6 40
    col7 80
    col8 0001

    Thanks
    Jr.

  2. #2
    Join Date
    Oct 2002
    Posts
    807
    Please do your home works before posting here. Metalink is a decent resource for such information.

    "The column is a bit vector that indicates which columns in the master table were changed by a DML statement."

  3. #3
    Join Date
    Jan 2002
    Posts
    148
    I understand, what change_Vector$$ column stores,
    but i need to decode the value so that i can rebuild the DML statement.
    Thanks
    Jr.

  4. #4
    Join Date
    Oct 2002
    Posts
    807
    For starters, what are you trying to? Trying to do a materialized view fast refresh? Do you understand how it works and what a snapshot log holds? Why do you care about this column? What DML?

  5. #5
    Join Date
    Jan 2002
    Posts
    148
    Can anyone else Know how to decode?

  6. #6
    Join Date
    Jan 2002
    Posts
    148
    Originally posted by Axr2
    For starters, what are you trying to? Trying to do a materialized view fast refresh? Do you understand how it works and what a snapshot log holds? Why do you care about this column? What DML?
    What are you trying to do -
    Cloned 850GB DB, and now trying to propogate the DMLs from the CLoned DB to Prod DB.
    Trying to do a Materialized view Fast Refresh? -
    - Kindof , cause, the trigger machanism to log into the Logtable is kernalized and it would be faster to UserDefinedTrigger.
    Do You understand how it works -
    Well, I dont know Oracle internals but i do know how documented stuff works.
    Why do you care about this column ?
    This column will help me to update only the afftected columns.
    Lets say, it has value '02' then i will update only the firstcolumn with new value for that RowID.
    What DML ?
    Based on DMLTYPE$$ Column valu , i will build the DML Statement.

    Got any answer for me now ?

    GoodLuck!!!

  7. #7
    Join Date
    May 2000
    Location
    ATLANTA, GA, USA
    Posts
    3,135
    You can do nothing. The change_vector$$ is internal to oracle.

    Tamil

  8. #8
    Join Date
    Oct 2002
    Posts
    807
    Originally posted by Jr
    Can anyone else Know how to decode?
    At this point, I assumed you didn't want my inputs and never bothered to see your next post.

    In any case, it should be fairly apparent by now that you can't do jack with that column. Looks like you are trying to rebuild the wheel..and are trying to rewrite Oracle's replication using triggers or whatever. Good luck with that. Good luck with finding documentation about internals.

    Might be better if you state what you are trying to accomplish (bigger picture) and someone might be able to suggest an alternate solution.

    Got any answer for me now ?
    See above.

    GoodLuck!!!
    It is you that needs it.

  9. #9
    Join Date
    Sep 2001
    Location
    Makati, Philippines
    Posts
    857
    Originally posted by Jr

    Got any answer for me now ?

    GoodLuck!!!

    Honesty, I am pretty impress by your motivation of doing your stuff.
    But haven't you thought of any other approach of doing what you want to accomplish?

    Why riding a boat(without a compass) of reaching to an island where in you can use helicopter to get there?

    Anyway, if I'll be in your shoes, I could just probably clone the db like doing a standby db, apply all logs to the standby db. And after all logs are applied, open the standby db and do those replication(materialized views,dblinks,etc.) and as long as you have correctly created this replications, Oracle will just automatically update those DMLs from PRODDB to CLONEDB or vice versa for you.

    regards,
    rey

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