We upgraded Oracle from 9i to 11gR last December. A procedure is running slower and slower: from 5 minutes to several hours. I manually analyzed the related tables. It then run fast again. We used to analyze all our tables weekly, we stopped doing that because we were told that we don't need to analyze table anymore in 11gR2 because Oracle will do it automatically. But the result indicated that we still need to manually analyze our tables. I am confused. Do we need to manually analyze our tables or not in 11gR2?