Partitions in Multidimensional Models (SSAS, SQL Server 2014)

In Analysis Services, a partition provides the physical storage of fact data loaded into a measure group. A single partition is created for each measure group automatically, but it is common to create additional partitions that further segment the data, resulting in more efficient processing and faster query performance.

Processing is more efficient because partitions can be processed independently and in parallel, on one or more servers. Queries run faster because each partition can be configured to have storage modes and aggregation optimizations that result in shorter response times. For example, choosing MOLAP storage for partitions containing newer data is typically faster than ROLAP. Likewise, if you partition by date, partitions containing newer data can have more optimizations than partitions containing older data that is accessed less frequently. Note that varying storage and aggregation design by partition will have a negative impact on future merge operations. Be sure to consider whether merging is an essential component of your partition management strategy before optimizing individual partitions.