I have been assigned the task of improving performance on one of our older transactional systems. One of the biggest failings of this system is the horizontal size of the tables. This is causing very poor read peformance. The five biggest tables in the database have 112,111,100,82 and 81 columns respectively. This is on tables that have 1 million plus rows. Then there are 100+ tables with 20+ columns. Does anyone have any tricks or solutions for dealing with tables of this size without going for a full re-design? The system is so functionaly overloaded a re-design would be an horrendous job. One of my first recommendations is to opimise the column data-types to reduce the width, e.g. at the moment a lot of them are NUMBER when INT would do. Then I am going to try and get data onto a RAID 5 array instead of the present RAID 1, this should help a little also. Any ideas would be appreciated.