Summary

BW needs much more performance tuning effort than R/3 does. To achieve acceptable performance, you must have a good understanding of the application and database design as well as the use of many advanced features provided with the underlying database.

Key Terms

Term	Description
BW Statistics	BW Statistics is a tool for recording and reporting system activity and performance information.
System Administration Assistant	System Administration Assistant is a collection of Assistant tools used to monitor and analyze general system operation conditions.
Read mode	The read mode for a query determines the size and frequency of data retrievals from the database: all data at once, as needed per navigation step, or as needed per hierarchy node.
Bitmap index	A bitmap index uses maps of bits to locate records in a table. Bitmap indices are very effective for Boolean operations in the WHERE clause of a SELECT statement. When the cardinality of a column is low, a bitmap index size will likewise be small, reducing I/O volume.
Partition	A partition is a piece of physical storage for database tables and indices. If the needed data reside in one or a few partitions, then only those partitions will be selected and examined for a SQL statement, thereby significantly reducing I/O volume.
Parallel query	A parallel query uses multiple database processes, when available, to execute a query.
Number range	A number range is a group of numbers that resides in application server memory and is available for quick number assignments.
Data packet size	For the same amount of data, the data packet size determines how work processes will be used in data transfer. The smaller data packet size, the more work processes needed.

For Further Information

SAP frequently updates the following two OSS Notes, which contain the most current information about performance tuning:

• OSS Note 0184905, "Collective Note Performance BW 2.0."

• OSS Note 0130253, "Notes on Upload of Transaction Data into the BW."

Other helpful OSS Notes include the following:

• OSS Note 0309955, "BW Statistics in 2.0B – Questions, Answers, Errors."

• OSS Note 0356801, "Performance Problems Based on a Wrong Optimizer Dec."

• OSS Note 0408532, "Using the DBMS_STATS Package for Collecting Stats."

• OSS Note 0351163, "Creating ORACLE DB Statistics Using DBMS_STATS."

• OSS Note 0156784, "Additional tablespaces for BW tables."

• OSS Note 0325839, "Considerable Increase of tablespace PSAPODSD."

• OSS Note 0339896, " ORACLE ERROR 14400" on Oracle partitions and parallel loads.

Next…

We will discuss how to transport BW objects from the development system to the quality assurance system and to the production system.