Loading Data into Aggregates Efficiently  

Setting Automatic Compression

You can set whether the aggregates of an InfoCube should be compressed automatically when it is filled with data or after being rolled up from data packages (requests).

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       1.      You are in the Modeling function area of the Administrator Workbench. In the InfoProvider tree, navigate to the required InfoCube.

       2.      Choose Manage In the context menu of the InfoCube. The Manage Data Targets dialog box appears.

       3.      Select the Rollup tab page in the lower part of the screen.

       4.      Under the Aggregates group area, set the corresponding indicator in the Compress After Rollup field.

Indicator	Information
set (default): Automatic compression switched on	The aggregates of an InfoCube are compressed automatically when they are filled with data or after being rolled up from data packages (requests). If you want to delete a data package (request) from the InfoCube and the InfoCube was already rolled up to the aggregate, you have to deactivate the aggregate and build it again.
not set: Automatic compression switched off	The aggregates are only compressed together with the InfoCube. Use this setting if you have to frequently delete requests from the InfoCube. A specific request can be deleted from the aggregates when it has been deleted from the InfoCube. Keep an eye on the performance because aggregates can become quite large if they are not compressed automatically.

Reading the Data in Blocks

If the amount of data is very large during filling, the system reads the data in blocks and not all at one time. This avoids problems with the temporary tablespace on the database if you have very large sources (InfoCubes or aggregates).

For more information about setting the block size see the implementation guide for the Business Information Warehouse -> General BW Settings -> Parameters for Aggregates.

Optimizing the Performance of Aggregates with Few Characteristics

Aggregates with fewer than 14 characteristics are created for all databases so that each characteristic is in a separate dimension and these dimensions are created as line item dimensions. Aggregates that only consist of line item dimensions are filled with pure database means. This improves the performance during filling and when rolling up.

The logical tree display in the right part of the screen of the Maintenance for Aggregate screen is copied from the left part of the Selection Options for Aggregates screen and does not mirror this special form of storage on the database.