Description
For InfoProviders that use multi-dimensional clustering (MDC) on DB2 forLinux, UNIX and Windows, this test determines the percentage ofallocated disk space that is free. If the free space is more than 33%,you should consider reclustering the InfoProvider.
An MDC table is physically organized such that data rows having the samevalues in the MDC dimension columns are grouped together into separateblocks. Every unique combination of values in the MDC dimension columnsforms a logical cell for which one or more blocks of pages may beallocated. The number of pages in a block corresponds to the size of thetable space in which the table resides.
The test displays the following detailed information about MDC spaceconsumption for the F and E fact tables of InfoCubes:

• Number of rows in the table


• Number of MDC logical cells for which blocks have been allocated


• Cardinality of the MDC dimensions


• Number of allocated pages in the table


• Number of empty pages in the table


• Allocated space for the table in KB


• Empty space for the table in KB

For each aggregate that uses MDC, the test provides the percentage ofspace allocated for the aggregate that is free. If the free space ismore than 33%, you should consider disabling MDC clustering for theaggregate.
The detailed information about MDC space consumption for DataStoreobjects is provided for the table containing the active data.
The test computes the information from the latest collection ofstatistics. If the database statistics are not current, the results maybe imprecise.

Repairs
This test provides no repair function.
Reclustering can be used to reduce space consumption for InfoCubes andDataStore objects. With reclustering, MDC clustering can be disabled orthe MDC dimensions can be changed. Reclustering is invoked from thecontext menu of the InfoProvider.
MDC clustering can be disabled for aggregates in the aggregatemaintenance screen by choosing Change Partitioning from theAggregate menu.