Hierarchy
SAP_BW (Software Component) SAP Business Warehouse⤷
BW-WHM-DBA (Application Component) Data Basis⤷
RSR_CORE (Package) Processor for Core Objects Reporting
Basic Data
| Data Element | RSRREADMODE |
| Short Description | Read Mode |
Data Type
| Category of Dictionary Type | D | Domain |
| Type of Object Referenced | No Information | |
| Domain / Name of Reference Type | RSRREADMODE | |
| Data Type | CHAR | Character String |
| Length | 1 | |
| Decimal Places | 0 | |
| Output Length | 1 | |
| Value Table |
Further Characteristics
| Search Help: Name | ||
| Search Help: Parameters | ||
| Parameter ID | ||
| Default Component name | ||
| Change document | ||
| No Input History | ||
| Basic direction is set to LTR | ||
| No BIDI Filtering |
Field Label
| Length | Field Label | |
| Short | 10 | Read Mode |
| Medium | 15 | Read Mode |
| Long | 20 | Read Mode |
| Heading | 0 |
Documentation
The read mode determines how the OLAP processor gets data during navigation. Three alternatives are supported:
- Read when navigating/expanding the hierarchy
In this method, the system transports the smallest amount of data from the database to the OLAP processor but the number of read processes is the largest.
In the "Read when navigating" mode below, data is requested in a hierarchy drilldown for the fully expanded hierarchy. In the "Read when navigating/expanding the hierarchy" mode, data in the hierarchy is aggregated by the database and transferred to the OLAP processor from the lowest hierarchy level displayed in the start list. When expanding a hierarchy node, the system intentionally reads this node's children.
You can improve the performance of queries with large presentation hierarchies by creating aggregates in a middle hierarchy level that is greater than or equal to the start level.
- Read when navigating
The OLAP processor only requests the data required for each query navigation status in the Business Explorer. The data required is read for each navigation step.
In contrast to the "Read when navigating/expanding the hierarchy" mode, the system always fully reads presentation hierarchies at tree level.
When expanding nodes, the OLAP processor can read the data from the main memory.
When accessing the database, the system uses the most suitable aggregate table and, if possible, aggregates in the database itself.
- Read everything at once
There is only one read process in this mode. When executing the query in the Business Explorer, the data required for all possible navigation steps for this query is read to the OLAP processor's main memory area. When navigating, all new navigation statuses are aggregated and calculated from the main memory data.
The "Read when navigating/expanding the hierarchy" mode has a markedly better performance in almost all cases than the other two modes. This is because the system only requests the data that the user wants to see in this mode.
The "Read when navigating" setting, in contrast to "Read when navigating/expanding the hierarchy", only has a better performance for queries with presentation hierarchies.
In contrast to the two previous modes, the "Read everything at once" setting also has a better performance with queries with free characteristics. The idea behind aggregates, that is working with pre-aggregated data, is least supported in the "Read everything at once" mode. This is because the OLAP processor carries out aggregation in each query view.
We recommend you choose the "Read when navigating/ expanding the hierarchy" mode.
Only use different mode to "Read when navigating/ expanding the hierarchy" in exceptional circumstances.
The "Read everything at once" mode can be useful in the following cases:
- The InfoProvider does not support selection, meaning the OLAP processor reads significantly more data than the query needs anyway.
- A user exit is active in the query that prevents the system from having already aggregated in the database.
History
| Last changed by/on | SAP | 20130604 |
| SAP Release Created in |
