Re: DB Links
- From: Jared Still <jkstill@xxxxxxxxx>
- To: mladen.gogala@xxxxxxxx
- Date: Thu, 23 Sep 2004 09:35:54 -0700
Hi Mladen,
Certain hints can be quite useful for certain applications.
The DRIVING_SITE hint would be one of those, along with
ALL_ROWS, FIRST_ROWS and others that are used to give
the optimizer a clue as to what type of response time is
needed from the query.
These are much less likely to cause future problems than
hints that give precise directions, such as USE_HASH,
USE_NL, INDEX etc.
Even those can be useful though when you have a performance
problem that needs an immediate solution.
The hint may not be the long term solution, but if it gets results
now, allowing time to correct the real problem, I don't see anything
wrong with that.
Jared
On Thu, 23 Sep 2004 10:46:30 -0400, Gogala, Mladen
<mladen.gogala@xxxxxxxx> wrote:
> I strongly dislike hints and I use them only when necessary.
> The problem with joins over the database link is that in situations
> like FROM EMP@LINK WHERE EMPNO = 1234, the whole EMP table will
> be brought over to the local site, stored in the temporary tablespace,
> much to the delight of users who want to do some sorting, and filtered
> locally, even in case that EMPNO is the primary key. How is it
> possible to filter remotely? Very simple, create a remote view, and
> access the view instead of the tables. I find that method to be much more
> portable and version independent then hints. Did I mention that I
> strongly dislike hints?
>
> --
> Mladen Gogala
> A & E TV Network
> Ext. 1216
>
>
>
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