Performance Optimization with SAP NetWeaver BI Accelerator  

Purpose

SAP NetWeaver BI Accelerator allows you to improve the performance of BI queries reading data from InfoCubes. The system makes the data of a BI InfoCube available as a BI accelerator index in a compressed but not aggregated form.

BI accelerator is particularly useful in cases where relational aggregates (see Performance Optimization with Aggregates) or other BI-specific methods of improving performance (such as database indexes) are not sufficient, are too complex, or have other disadvantages.

For example, if you have to maintain a large number of aggregates for one particular InfoCube, you can use the BI accelerator to avoid this high maintenance effort. Unlike performance optimization with aggregates, there is only one BI accelerator index for each InfoCube. As with performance optimization with aggregates, you do not have to make any decisions regarding modeling for the BI accelerator index.

Implementation Notes

The BI Accelerator is based on TREX technology. To use the BI accelerator, you need an installation based on 64-bit architecture. Hardware partners deliver this variant in preconfigured form as the BI accelerator box. Note that you cannot use a TREX installation configured for searching in metadata and documents with the BI accelerator since TREX installations are based on 32-bit architecture. Equally, you cannot use a BI accelerator box for searching in metadata and documents. If you want to use the search function as well as the BI accelerator, you require two separate installations.

For more information, see the following SAP Notes:

883726 TREX 7.0: Central Note SAP NetWeaver BI accelerator 

902533 TREX 7.0: HowTo Guide Connecting/Operating BI Accelerator Box  

Integration

Accessing the OLAP Processor

You can use relational aggregates and a BI accelerator index for the same InfoCube. A BI 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.      BI Accelerator index

       3.      Relational aggregates from the database

       4.      InfoCubes from the database

If an active BI accelerator index exists, the OLAP processor always accesses this BI accelerator index and not the relational aggregates. Therefore, with regard to modeling, we recommend that you create either relational aggregates or a BI accelerator index for an InfoCube.

Query Execution

When the query is executed, it is clear to the user whether data is being read from an aggregate, a BI accelerator index, or an InfoCube.

In the maintenance transaction, you can deactivate a BI accelerator index on a temporary basis to test it for performance purposes or to analyze data consistency.

You can also execute the relevant 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 BI Accelerator Index to execute the query with aggregates or an InfoCube. 

 More Information

You can find detailed documentation on the BI Accelerator under Administration of SAP NetWeaver BI Accelerator → Administration Tasks on Demand → Manage BIA Indexes. .