Re: How to tune a huge SELECT ?

Christian Svensson wrote:

> Greetings,
>
> We have in our Datawarehouse solution Cognos as end user application.
> Cognos reads from our different datamarts to build its own cubes.
>
> Since these SELECT get a lot of data, we are talking about approx 100
> million rows. It takes approx 7-8 hours for Cognos to select this data
> into a Cognos tempfile where it later use this to build the cubes.
>
> What I wonder is what Oracle setting/tuning can you make when you want
> to get this amount of data from the database ?
>
> I am open for any suggestions.
>
> Thanks.
>
> Cheers !
>
> /Christian

Can you control the SQL statements? If so then EXPLAIN PLAN each and every one. See if indexes are being used. See if the correct indexes are being used. Determine what is taking the most time. Attack it first. And are you trying to move that 100 million rows across some wire to another machine? If so don't leave your network out of the calculation.

Daniel Morgan Received on Fri Sep 06 2002 - 10:53:41 CDT