We have a DB which has around 500 tables and they are in first normal form. That is why we have deadly performance on productional environment. Full tables scan is common. The biggest table has 264 fields, 15 indexes which include 108 table fields. At the beginning as I understood they was trying to create db in only one table, and just added new fields and indexes. Our product is huge and rebuild everything is very difficult as everything must be done from the beginning. Sort operations takes by 15M number of opened cursors exceed 450 for one user.
Problem is next, I don't know how to improve performance without rebuilding whole structure and I don't know how to explain that to my boss.