Re: NOLOGGING and index

In article <9qjnt0$1po0$1_at_ns.felk.cvut.cz>, "Ales says...
>
>Hi again,
>I see I was a bit verbose last week, so I try to summarize it:
>
>I found that in case of direct-load INSERT, indexes on the populated
>NOLOGGING table generate significant amount of redo regardless of their
>NOLOGGING status.
>
>Could anybody confirm or disconfirm that?
>
>Thanks in advance,
>Ales
>
>
>
>

Yes, it makes sense when you think about it...

The TABLE data is just written above the HWM. If we need to "rollback", we just never advance the HWM.

For the indexes however, a complex data structure, our new data is intermingled with the old data. In the event of a rollback -- we have to be able to UNDO all of the work we just did to that index.

the direct path insert can be used to load a table without much redo genearation but the indexes must be fully protected as we load.

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Thomas Kyte (tkyte@us.oracle.com)             http://asktom.oracle.com/ 
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