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).
...
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.
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