Performance Optimization
Purpose
A variety of functions are provided to help you improve the performance of your BW system. These functions cover the following areas: database, query, and load performance.
As well as the functions listed here, other functions in InfoProvider modeling also affect performance.
If you use your BW system together with the SAP HANA database, only some of the functions specified here are of significance, namely snapshot indexes for queries and VirtualProviders, and non-cumulatives.
Features
The following sections provide detailed descriptions of BW functions for performance optimization:
● Using the SAP HANA Database Instead of an SAP NW BWA
● Creating and Managing BWA Indexes in the BW System
● Performance Optimization with Aggregates
Accessing the OLAP Processor
You can use relational aggregates and a BW accelerator index for the same InfoCube. A BEx query always tries to use performance-optimized sources by checking the sources from which it can draw the requested data. It checks the sources in the following order:
...
1. OLAP Cache
2. BW Accelerator Index
3. Relational aggregates from the database
4. InfoCubes from the database
If an active BW accelerator index exists, the OLAP processor always accesses this BW accelerator index and not the relational aggregates. In terms of modeling, we therefore recommend creating either relational aggregates or a BW accelerator index for an InfoCube.
Query Execution
When the query is executed, the user can tell whether data is being read from an aggregate, a BW accelerator index or an InfoCube.
In the maintenance transaction, you can deactivate a BW accelerator index temporarily to test it for performance purposes or to analyze data consistency.
You can also run
the relevant query in the query monitor(transaction RSRT) using the debug
option (Choose 
Execute + Debug). In
the Debug
Options dialog box, choose
Do Not Use
BW Accelerator Index to
execute the query with aggregates or an InfoCube.