System Response Upon Changes to Data 
The following sections explain what you need to bear in mind if the data in the underlying InfoCube changes when using SAP NetWeaver BW Accelerator indexes.
For information about hierarchy/attribute change runs with SAP NetWeaver BW Accelerator indexes and special cases where it might be necessary to restructure a BW Accelerator index, see System Response When Data Changes: SAP NetWeaver BW Accelerator Index.
For information about optimizing the performance of frequently used BW Accelerator indexes, see Improving Efficiency Using BWA Delta Indexes.