Subject | Re: [ib-support] need help on query optimisation |
---|---|
Author | Svein Erling Tysvaer |
Post date | 2002-10-08T07:11:09Z |
Hi Ben!
...
When Ben Johnson says something is lightening fast, it certainly is
extremely fast (sorry, couldn't resist). What really matters to help is
your plan, which you do not quote. Still, with your information about
lightening fast, it is easy to solve. Simply add a bit to that line:
AND ( ( products.company_id = :dCID ) OR 4=2)
The reason this should work is because it has to be a change in the plan
that makes the query crawl. Introducing the OR bit prevents the optimizer
from doing this change, and anything always evaluating to false will do (I
chose 4=2 simply because of a soccer result the other day).
Set
...
>It is taking a lot of time. But if I remove the last line it is lightning...
>fast. I can't go
>without that last line if I need to select only a company's product.
When Ben Johnson says something is lightening fast, it certainly is
extremely fast (sorry, couldn't resist). What really matters to help is
your plan, which you do not quote. Still, with your information about
lightening fast, it is easy to solve. Simply add a bit to that line:
AND ( ( products.company_id = :dCID ) OR 4=2)
The reason this should work is because it has to be a change in the plan
that makes the query crawl. Introducing the OR bit prevents the optimizer
from doing this change, and anything always evaluating to false will do (I
chose 4=2 simply because of a soccer result the other day).
Set