A successful SAP BW implementation requires that end user query response times are consistently running in the fast to reasonable range, in order to gain user acceptance and help drive overall productivity. There are many factors that influence the response time of a BW query, including its complexity, the volume of data involved, architecture of the data model, and the existence of pre-summarized or pre-calcultated objects. A sound OLAP performance strategy includes the utilization of several of the important tools that are available for SAP BW tuning efforts, such as multi-provider, aggregates, and pre-calculated templates. Introduced in SAP BW version 3.0, the OLAP cache offers a valuable compliment to these other useful techniques used for accelerating query response times.
The OLAP cache is architected to store query result sets, and to give all users on an application server access to those result sets. If a user executes a query, the result set for that query’s request can be stored in the OLAP cache. If that same query (or a derivative) is then executed by another user, the subsequent query request can be filled by accessing the result set already stored in the OLAP cache. In most cases, a query request filled from the OLAP cache is significantly faster than queries that receive their result set from database access.
A savvy performance tuning strategy could include scheduling background jobs to load specific query result sets into the OLAP cache. Therefore, initial user query executions against newly loaded data can “hit” and OLAP cache result sets in running queries, boosting performance significantly. For more information about performance tuning in general, see also SAP Service Marketplace alias /bw -> Performance.
View/Download the Manual on Performance Tuning.
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