Rotation slice

        GBase 8s Generally speaking, the fragmentation method can be divided into two categories ： The first category is Rotation segmentation ; The second type is Expression based The way .

         Rotation method GBase 8s Provided internally The hash algorithm , Distribute the data evenly in different places Table space On .

         The expression based segmentation method is based on the user The defined expression puts The data is distributed and stored in a predetermined location Table space On , The distribution mode of data is completely specified by the user according to the characteristics and access of data .

         The rotation method adopts GBase 8s Provided internally The hash algorithm Uniform distribution of data , It's simple to use , There is no need to know the fragmentation of data . Rotation method Can only be applied to table , You can't The index is segmented by this method . Simultaneous rotation method You can't Use the feature of ignoring fragmentation in the fragmentation table to reduce the scanning of disk by query , But for applications that need to scan most of the data , Use The rotation method can be used PDQ Enable multithreading Parallel scanning , Improve query performance .