SQL & PL/SQL

Hi there

I have a query that runs against our Oracle database in the US.
I have the query optimized and running quickly.

Now I need to join this query to a table in my local database, but whenever I do so my query time drops significantly.
I have tried rewriting the query at least 5 different ways, but nothing has helped.
I indexed the local table when I created it, but this did not seem to make any difference.

It says in my explain plan that I am doing a full table scan on my local table - should I try to avoid this?

Any suggestions welcome.

I will post explain plan or queries - if it will help.

Thanks