Oracle Database Discussions

Hi, I have an Oracle RAC 10GR2 (10.2.0.4) on 2 nodes with Suse Linux Enterprise Server.

I have tables with 300.000.000 of records. I've been created some indexes for don't appear the table access full access. I create one index for each foreign key similar to http://blog.go-faster.co.uk/2007/10/tm-locking-checking-for-missing-indexes.html

The performance was better after create all the indexes. However, some of index, for example PK_CASVAL index which correspond with the primary key of the table casval (300M of records). When I explain plan for select of that table for it's primary key, the plan don't use the index and it use table access full.

I'm reading and looking for the google, and I think is relative of clustering factor. Some authors says that I should have to rebuild or coalesce indexes, or reorganice, and another says that rebuild is not necessary.

What is your advice and How can i do it?

Thanks you very much!!!