How MDC Tables Work
MDC enables a table to be physically clustered on more than one dimension simultaneously. Without MDC tables, DB2 UDB would only be able to relationally support single dimensional clustering of data via a clustered index. With MDC, these benefits are extended to more than one dimension or clustering key.
In the case of query performance, queries involving any, or combination thereof, specified dimensions of the table will benefit from clustering. Not only will these queries access only those data pages having records with the correct dimension values; these qualifying pages will be colocated as well. Furthermore, although a table with a clustering index can become unclustered over time as space fills up in the table, an MDC ...
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