Going in Production - Expert Cube Development with SSAS Multidimensional Models - page 298

Dimension processing
In this section, we will discuss the various different types of processing that can be
performed on a dimension and what they actually do. For obvious reasons, we'll
want to choose the option that loads the data we need into the dimension in the
quickest and most efficient way. However, when processing a dimension, we also
need to be aware of the side effects that this processing might have on any cubes
that the dimension is present in. If, for example, we perform a Process Update on
a dimension, this might invalidate aggregations that include hierarchies from this
dimension, meaning they need to be rebuilt too. In this case and others, the side
effects are more significant than dimension processing itself: the processing of a
single dimension is usually a relatively fast operation, while rebuilding aggregations
can take much longer.

Clicking on the Impact Analysis button in the Process dialog in
either SQL Management Studio or SQL Server Data Tools will
list all of the objects that are affected by any type of processing
on any object.

Here is a complete list of all of the options we have for dimension processing, along
with a brief description of what each one does and any side effects:

Type Description

Full The dimension's structure is deleted and rebuilt. All dimension data is

reloaded from scratch. In addition, all partitions of all measure groups
related to this dimension require a Full Process before they can be queried.

Add Compares the contents of the relational dimension table with the contents of

the Analysis Services dimension and adds any new members that are found
but does not delete or update existing members: this means that you run the
risk that important changes to existing dimension members are not made. It
does not invalidate existing partition data or aggregations.
Also known as incremental processing, this option is not visible in SQL
Management Studio or SSDT. For more information on how to use Process
Add, see http://tinyurl.com/gregprocessadd .

Data Loads data into the dimension but does not process dimension indexes. It

has the same side effects as Process Full.

Index Usually used after Process Data, it builds the bitmap indexes of the

dimension and does not require any access to the relational database.