Tuning SQL in Oracle

I have some fairly complex queries (joins to 20 tables etc) that run fine using the rule based optimizer, but simply die using the CBO. Can anyone offer any hints or point me to a book, web resource, etc. that will help me tune these correctly using the CBO? I'm using /*+ Rule*/ as a stopgap measure because we're running 8.1.7 right now, but our move to 9i is coming soon, so I really need to get these running efficiently using cost based optimization.

Thanks in advance for any help you can offer. Received on Wed Jul 30 2003 - 20:17:42 CEST