Hi,
first you should be able to set the optimizer goal per session using
SET OPTIMIZATION FIRST_ROWS
secondly how do you see that the optimizer hints (that is what you
mean, right?) are not used? Do you have any helpfull output?
(I had to use optimizer hints with Informix only in some rare
occasions where the data structures where messed up and
had to stay like that for some 'good' reasons ;-) )
Regards,
Dirk
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--
-- Dipl.-Math. Dirk Gunsthövel
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--
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-- 'One now understands why some animals eat their young.'
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"Joerg Rueschenschmidt" <jrueschenschmidt@[EMAIL PROTECTED]
> schrieb im
Newsbeitrag news:486FD4D5.3000706@[EMAIL PROTECTED]
> TBP schrieb:
>> Joerg Rueschenschmidt wrote:
>>> Joerg Rueschenschmidt schrieb:
>>>
>>>> Hi all,
>>>>
>>>> Is it possible to use Informix external directives for statements
with
>>>> host variables ?
>>>>
>>>> It works fine for statements without host variables.
>>>>
>>>> Now, I need to solve a problem for a statement with a host variable.
>>>>
>>>> e.g.
>>>>
>>>> ... WHERE (a0.t_ncst > ?)
>>>>
>>>> If I add a statement with host variables my directive is not used :-(
>>>>
>>>> I am afraid that I can not benefit from external directives if host
>>>> variables are used.
>>>>
>>>> Can someone confirm this ?
>>>>
>>>> Regards ...
>>>>
>>>> Joerg
>>>
>>>
>>> Sorry, I missed to mention my Informix version is IDS 10.00.FC8 on
>>> Linux.
>>>
>>> Regards ...
>>>
>>> Joerg
>>
>> Why do you HAVE to use directives?
>>
>> Directives are really there just to claim equivalence for other DMBSes.
>>
>> Hopefully, the IDS optimiser produces good plans, if not, then perhaps
>> directives as a workaround to a defect in the optimiser.
>
>
> To give you a short answer. Our IDS is configured to use OPT_GOAL=-1
> (ALL_ROWS). The goal is fine for almost all queries in our application,
> but in a few situations I would prefer to have FIRST_ROWS behavior.
>
> This is why I would like to use external directives.
>
> However, my main question is :
>
> Is it possible to use Informix external directives for statements with
> host variables ?
>
> Regards ...
>
> Joerg
>
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