Re: Informix external directives ?

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