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.
The following figure provides an overview of index local buffers when table data and index data are respectively allocated to local buffers.
Figure 11-6 Overview of index local buffers