selecting ROWNUM causes query to take forever

[Paul Bradford]

I have a query that takes about two minutes and returns 97 rows.
If I change the query only by adding ROWNUM to the outermost
select clause, the query never returns (I let it run overnight).
I'm not using ROWNUM in the where clause, I'm just selecting it.
I can't think of any reason that just selecting ROWNUM would make any
difference. This is Orace 8.1

I spent a day searching Google groups without finding anything on this.

Any ideas?

Thanks in advance,

Paul

[Frank]

Re: selecting ROWNUM causes query to take forever

Paul Bradford wrote:

I have a query that takes about two minutes and returns 97 rows.
If I change the query only by adding ROWNUM to the outermost
select clause, the query never returns (I let it run overnight).
I'm not using ROWNUM in the where clause, I'm just selecting it.
I can't think of any reason that just selecting ROWNUM would make any
difference. This is Orace 8.1
>
I spent a day searching Google groups without finding anything on this.
>
Any ideas?
>
Thanks in advance,
>
Paul
>
>

Crystal ball is in the repair shop. Why not post the query, explain
plan, etc?

--
Regards, Frank van Bortel

[Paul Bradford]

Re: selecting ROWNUM causes query to take forever

Paul Bradford wrote:

>

I have a query that takes about two minutes and returns 97 rows.
If I change the query only by adding ROWNUM to the outermost
select clause, the query never returns (I let it run overnight).
I'm not using ROWNUM in the where clause, I'm just selecting it.
I can't think of any reason that just selecting ROWNUM would make any
difference.

For reasons I don't understand, adding ROWNUM caused a different
(and worse) execution plan. After I added some hints to get a good
execution plan, my problem is solved.