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  1. #1
    Join Date
    Jan 2004
    Posts
    66

    Unanswered: Delete-Insert OR Merge

    Hi,

    A table has 500 millions of rows . Now I have to update around 0.4 million of rows in the table.

    Can you tell me which process would be faster for this criterian :

    1. Delete-Insert (Deleting the existing rows and Insert the updated rows)

    2.Merge(Update else Insert)

    Thanks ..
    himridul

  2. #2
    Join Date
    Apr 2003
    Location
    Greenville, SC (USA)
    Posts
    1,155
    I would have to say that your "merge" method would be better. If the table has indexes on it, delete will have to "mark" the index row for deletion, then find available node space for the insert, as well as the delete/insert to the table data blocks.

    Use a large rollback segment or commit often.

    Gregg

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