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Best Practices for SAP BI using DB2 9 for z/OS - IBM Redbooks

Best Practices for SAP BI using DB2 9 for z/OS - IBM Redbooks

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For example, assume that different plants deliver their data at different times<br />

to be loaded into an InfoCube. It would not be valid to make any of the data<br />

visible until all plants have delivered their data to be loaded into the InfoCube<br />

as a consistent set.<br />

► Another option to start the roll-up manually is by executing the program<br />

RSDDK_AGGREGATES_ROLLUP. This program can either be scheduled<br />

periodically or an event chain can be constructed to include aggregate roll-up.<br />

Change-run: hierarchy-attribute realignment run<br />

If you change master data, navigation attributes or hierarchies usually change as<br />

well. We there<strong>for</strong>e recommend that you adjust the data in the aggregates after<br />

loading the master data. To assure that reporting delivers consistent results, the<br />

master data and hierarchies are kept in two versions:<br />

► The active version, where you can see the query<br />

► The modified version, which at some point will become the active version<br />

The change-run, also called hierarchy-attribute realignment run, adjusts the data<br />

in the aggregates and turns the modified version of the navigation attributes and<br />

hierarchies into an active version. In almost every phase of the change-run, you<br />

can continue reporting on the old master data and hierarchies.<br />

You can either start the change-run manually in the Administrator Workbench or<br />

with the program RSDDS_AGGREGATES_MAINTAIN. You can give the<br />

program a list of characteristics and hierarchies that are to be taken into account<br />

<strong>for</strong> the change-run. By default, all those characteristics are taken into account<br />

whose master data you loaded or changed manually, and all the hierarchies that<br />

were marked <strong>for</strong> the realignment run.<br />

The change-run takes places in different phases:<br />

► A list is generated of all navigation attributes and hierarchy levels that have<br />

changed. Then the relevant aggregates that are to be adjusted are generated<br />

from this list.<br />

► The system adjusts the aggregates and calculates the percentage of change<br />

per aggregate. If the percentage is small, the changes are calculated<br />

explicitly. If the percentage is large, the aggregate is completely rebuilt in a<br />

temporary table.<br />

► Master data and hierarchies are activated.<br />

► The temporary aggregate tables are renamed. When running on <strong>DB2</strong>, the<br />

indexes are also renamed at this stage.<br />

272 <strong>Best</strong> <strong>Practices</strong> <strong>for</strong> <strong>SAP</strong> <strong>BI</strong> <strong>using</strong> <strong>DB2</strong> 9 <strong>for</strong> z/<strong>OS</strong>

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