Hi, We are working on a project which will have very big tables (at least very big in my opinion). Initially we estimate that in three tables of our database we will have between 30 million to 60 million records (each one). We think very soon we will have more than 100 million records in each of this tables. Also each record will have on average 120 sub records. To avoid even a bigger table size we are going to store these sub records in main record. This sub records are simple and are a pair of key and value. We are not sure which one is better, to store as an array or a serialized object (we are using java on server) or other solution which we are not aware of it. There is not a performance issue with this sub records as these sub records will not participate in any query and the only time we need them is when we have found the record and are extracting it's complete details (or insert/update). So my question is, As a database admin what would you do with this kind of database and it's big tables? Is it a good idea to try to break those tables to sub tables (dividing by inheritance and say first letter of primary key), or clustering is enough, Or any other solution? And what is your opinion about sub records? Thanks in advance. David. ____________________________________________________________________________________ Park yourself in front of a world of choices in alternative vehicles. Visit the Yahoo! Auto Green Center. http://autos.yahoo.com/green_center/