Thanks, Wolfgang! K. Gopalakrishnan also pointed that to me. I must say
that I prefer parameters to a very broad sword and that I'm perfectly
content with hints. Why do hints cause such a controversy? They're only
a fine tuning tool which are needed only when fine tuning is needed.
Another instance of need for hints is when one of the tables involved
in a join is in a hotspot and even if a full table scan would normally
be the fastest way to read it, you want to use fast full index scan,
just
to avoid it. Optimizer has no way of knowing about misteries of disks,
universe and everything. For such cases, we need hints.
On 2003.05.14 22:06 Wolfgang Breitling wrote:
> If you have many of those, try setting _LIKE_WITH_BIND_AS_EQUALITY =
> TRUE (can be done with alter session) and potentially increase the
> selectivity of the column by reducing density by an order of
> magnitude or two.
>
> At 04:11 PM 5/14/2003 -0800, you wrote:
>> [...]
>
>> The contention issue are the bind variables from PRO*C programs where
>> things "LIKE :S" are usually resolved by using a full table scan,
>> even if :S is of the form 'ABC%' in which case the query should, as
>> we all know, use an index. The only solution that I have for the
>> problem
>> is to put a dreaded hint in the select.
>
> [...]
> Wolfgang Breitling
> Centrex Consulting Corporation
> http://www.centrexcc.com
>
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Received on Wed May 14 2003 - 22:26:58 CDT
