Merge WriteBack Table utility

Run the Merge Writeback Table utility on a regular basis to improve performance if you are writing large amounts of data. It also performs other database cleanup. For example, plan objects are not actually deleted until you run this utility.

When you process the cube in Analysis Services, it gets the values from the fact table and creates a cache with those values and some aggregations. When you change data, the values in the fact table are not updated. Instead, the incremental change to the values are written to a separate Writeback table in the database. Analysis Services sums these values with the value in memory to provide the data value in a request.

Because Analysis Services does not use values in the fact table except during the process of the database, you must first make sure the values in the fact table are up to date before changing the values in the fact table. This is what the MergeWriteback utility does; it merges the values in the Writeback table with the values in the fact table, and updates the fact table with the combined value. You can then update the fact table with your own data and process the database.

Since Analysis Services sums the combined values in the writeback table with the value in memory, having large amounts of data in the writeback table can affect performance.

This utility is installed on the CPM Server computer and is run from the Merge Writeback Table Utility program item under Strategy Management.