If data local buffers and index local buffers are defined separately, data retrieval and index retrieval will be conducted independently even if they are performed concurrently. Therefore, even if a large amount of data is to be retrieved under all conditions, the frequency of index input/output can be reduced and processing time can be shortened.
Figure 12-6 provides an overview of index local buffers where local buffers are allocated for both table data and index data.
Figure 12-6 Overview of index local buffers