Performance Optimization
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.
The following sections provide detailed descriptions of BW functions for performance optimization:
- Using the SAP HANA Database Instead of SAP BW Accelerator
- Creating and Managing BWA Indexes in the BW System
- Performance Optimization with Aggregates
- Non-Cumulatives
- OLAP Cache Monitor
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:
- OLAP Cache
- BW Accelerator Index
- Relational aggregates from the database
- 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. Therefore for modeling, we recommend that you create 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 execute the query in the Query Monitor (transaction RSRT) using a corresponding 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.