Using SQL Server 2012 Column-Store with SAP BW
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© 2012 SAP AG 10
Configuring Column-Store in SAP BW
To use the column-store for SAP BW cubes, you first have to define the cubes, which should have a column-
store index on the e-fact table. This definition is stored in an SAP Data Dictionary table. The next step is to
convert the e-fact table by dropping unnecessary B-Tree indexes and creating the column-store index. You
can perform both steps either separately or within a single job using SAP report MSSCSTORE.
Defining cubes with Column-Store index
The Data Dictionary table MSSSTORAGE contains SQL Server specific storage parameters and global
settings. For each e-fact table using the column-store, there is a row in table MSSSTORAGE. You can use
report MSSCSTORE to change the settings in table MSSSTORAGE.
Note: Table MSSSTORAGE contains additional rows that are not related to the column-store. Do not modify the content
of table MSSSTORAGE manually. Always use report MSSCSTORE.
Converting cube according to definition
Defining the column-store index for an SAP BW cube is very fast, since it only modifies the SAP Data
Dictionary. Actually converting a cube can take some time. Therefore, we recommend running the
conversion always as a batch job. During the conversion to the column-store, several b-tree indexes are
dropped and a column-store index is created. When converting back to the row-store, the b-tree indexes
have to be re-created. Actually, converting the cube is nothing else than repairing the indexes of e-fact table
according to the definition stored in table MSSSTORAGE.
Note: Creating indexes, in particular b-trees, requires a significant amount of system resources: CPU, memory, I/O and
data and log space on the database. In a typical BW system, process chains drop and create indexes the whole
day. To reduce the required transaction log space, it might be a good idea to set the SQL Server recovery model
to Bulk-logged. Keep this in mind when setting up your backup strategy for the database of your BW system.
There are several ways to convert a BW cube from row-store to column-store, and vice versa:
Report MSSCSTORE
Using SAP report MSSCSTORE is the easiest way to convert the BW cube. SAP strongly recommends
running the report as a batch job. MSSCSTORE is described in detail below.
Activate empty cube
If an SAP BW cube is empty, a cube activation creates all database tables and indexes dependent on the
configuration in MSSSTORAGE. Therefore, you can simply convert an empty cube by activating it in SAP
transaction RSA1.
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