Mpit stores the complete predicate information of each transaction in the database and divides it into a series of subsets according to different predicates . after that build itemsettree to process each of them Mpit记录了数据库中所有的维谓词信息，同时将数据库按不同的维谓词分割成了一系列很小的子集，然后对各子集部分建立有序大项集树。
