>From: Mladen Gogala >Laimutis, you may want to take a look at my website (http://www.mgogala.com). That one http://www.mgogala.com/Manipulating_CBO.pdf is good. In memorum: This article explains why I have moved from development to dba. I betrayed, I left the other developers to deal with this craziness of reinventing a wheel 10^n'th of time. I left them to deal with those vendors who in their hastiness to build and sell yet another product version forgot what essential features the previous version had. Crazy, crazy software world. PS: Regarding "Therefore, I find recommending the parameter based "silver bullet" approach most effective and the easiest to implement": Yes, for a well tuned system I was setting those parameters just to index_cost=0, caching=100. Rude, but works for tuned applications. However, this approach does not work at all for "a man must not have to think" applications. This is where CBO unleashes its power. Fyrirvari/Disclaimer http://www.landsbanki.is/disclaimer -- //www.freelists.org/webpage/oracle-l