Re: USE_MERGE hint and the correct way to hint

Nice example to explain this.

I cheated with the query, to make it look simple I put a select *, though there were no columns selected from CUS_ACC.

Thanks,
Arul

On 2/7/07, Nigel Thomas <nigel_cl_thomas_at_yahoo.com> wrote:
>
> >I played around with changing the order of the tables
> >in the FROM clause and in the use_merge hint. It does
> >change the order in the plan, but the logical reads come
> >to the same.
> Arul
>
> A merge join is like a zipper - you take two (sorted) rowsets and read
> through both of them concurrently. So (in principle, in a simple case)
> there's no difference between merge-joining A to B or merge joining B to A;
>
>
> I'm intrigued that there's no table access to CUS_ACC. Does that contain
> only the ACC_ID column, whose value we can derive from the PK_CUS_ACC index?
> Or is it index-organised?
>
>
> Nigel
>

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