Re: RBO changes plan from 8i to 9i

Hi Alex

Those changes only affects very simple Deletes such as

delete x where x_id = 1

The predicate must be part or all of a single index, if there are references to other columns then you will still see table access. I am not sure what this is called.

And by the way to disable nested loop parallel scan with multi join keys you can set _multi_join_key_table_lookup to FALSE and leave _table_lookup_prefetch_size with its default value. I am not sure which is betetr idea, I would guess modifying _multi_join_key_table_lookup might be a better approach since I am not sure what other features you are disbaling by setting _table_lookup_prefetch_size to cero.

Regards

On 7/13/06, amonte <ax.mount_at_gmail.com> wrote:
>
> Hi again
>
> I just noticed some minor changes in DELETE plans as well, instead of
>
> DELETE STATEMENT null
> DELETE null
>
> TABLE ACCESS BY INDEX ROWID
> INDEX RANGE SCAN
>
> in 8.1.7.4 I see now
>
> DELETE STATEMENT null
> DELETE null
> INDEX RANGE SCAN
>
> Again it's very minor change, table access is no longer needed.
>
> What is this new feature called...?
>
> Thanks
>
>
> Alex
>
>

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