Problems with OR in Oracle 8i

Hi All,

I have a fairly big Oracle 8i database (2 million order rows in the largest table) and I'm having trouble with the OR operator in a query. For some reason the OR is causing queries to run dog slow. It's so slow that I have to take out the OR and use a UNION instead. For example:

this takes 5 minutes to run:

    select * from sales_order, customer where customer.customer_code=sales_order.customer_code and salesmen1='person1' or salesmen2='person1'

this takes a few seconds to run and returns the same result:

    select * from sales_order, customer where customer.customer_code=sales_order.customer_code and salesmen1='person1'

    union
    select * from sales_order, customer where customer.customer_code=sales_order.customer_code and salesmen2='person1'

Almost every time I use an OR on a moderately complex query on a big table the thing takes forever. Is there a problem with the 8i optomizer? These unions get cumbersome, especially if there are lot's of OR conditions to account for.

Thanks,
Dan Received on Wed Jan 04 2006 - 09:46:28 CST