Re: Speed up a query - using a temp table

David,

You should post performance related items to the
PERFORMANCE mailing list.

To answer your question a few ideas to try.
I think you only pasted a partial query.
Why do you need the OUTTABLE in the first place?
If you do why not put the WHERE clause inside?

select contact.id
, contact.name
, (select SOMETHING_MISSING from detail inner join
myDetail using
(detail.id) ) as cost
from contact
inner join user using (user_id)
WHERE_CLAUS_MISSING???and user_id = 1
where cost > 30;


Regards,
Nikolaus Dilger


David Wendy wrote:

>
> I have a query of the form:
>
> select * from (
> select contact.id
> , contact.name
> , (select from detail inner join myDetail using
> (detail.id) ) as cost
> from contact
> inner join user using (user_id) and user_id = 1
> ) as OUTTABLE
> where cost > 30;
>
>
> The problem is that all the tables in the query are
> big, so it takes a
> long time to get results from OUTTABLE (around 20
> seconds) . When I
> add the where clause at the end (cost > 30), the query
> becomes too
> long (around 200 seconds sometimes).
>
> To make the query run faster, I thought of creating a
> temp table to
> store OUTTABLE, and then just filter on the temp table
> using cost >
> 30. That would improve the speed of the query
> tremendously (total time
> was around 23 seconds) . The problem with that
approach
> is that I'm
> writing an application, and more than one user might
> need to run the
> query at the same time. (Different user should get
> different results
> because they have different user ids, and other
numbers
> in the query
> would be different). Also, I can't just create and
drop
> temp tables in
> an enterprise application (we are not using ejbs in
our
> applications
> either), it seems like bad style.
>
> Anyhow, how could I make this query faster so that the
> values of
> OUTTABLE is retrieved first, then the where clause is
> evaluated to
> filter?
>
> Thanks in advance.
>
>
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