Partition Planning: Based Upon Resource Assignments and Settings
Services, we can split individual measure groups into multiple partitions,
which can each have different resource assignments and settings. When planning
partition design, we need to consider each of these options to optimize our
overall solution in our own environments. We will discuss some of these resource
assignments / settings in the individual subsections that follow. In each
case, we will take a look at existing settings in the sample UDM. (We will
actually create and work with partitions in articles dedicated to various
aspects of doing so in other articles of this subseries.)
As we discussed earlier, we can create a partition or partitions for non-current
/ historical time frames that experience light querying, and enact minimal (or
even no) aggregations for such a partition(s). In contrast, we can plan to add
more aggregations into partitions that experience heavier use, to enhance query
performance. Planning partitions around the degree of aggregation, based upon
the expected degree of querying, is one of the most common planning
Aggregation Settings: To see an example set of aggregation settings, lets
take a look at the Internet Sales measure group within the Cube Designer of the
Business Intelligence Development Studio. From the Partitions tab, we use the Measure Groups pane to manage the partitions
associated with each measure group in the cube.
On the Partitions
tab, ensure that the Internet Sales measure group (the top group in a list of
eleven groups), which indicates the presence of four (4) partitions, is open by
clicking the two upward pointing carets (if the measure group is not already
open by default), as shown in Illustration 17.
Illustration 17: Open the Internet Sales Measure Group, if Necessary ...
pane displays a grid containing the list of partitions that support the
selected measure group. Partition
settings for the Internet
Sales measure group appear, as depicted in Illustration 18.
Illustration 18: Settings for the Internet Sales Measure Group Appear
Of specific interest to us within this
subsection is the Aggregation column of the Measure Groups pane. The Aggregation Design column references the aggregation
design established for the partition. For the first partition supporting the Internet
Sales measure group, we see that that the Internet Sales aggregation design is
referenced. Lets take a look at the aggregation design settings themselves,
by accessing the Aggregations tab from our current position.
Click the Aggregations
tab, as shown in Illustration 19.
Illustration 19: Transiting to the Referenced Aggregation Design ...
The Aggregations tab displays the Aggregations that
exist within our cube. The top item in the list, Internet Sales, is our focus
at present. Lets open this measure group to see the assigned aggregation
Sales by clicking the + sign to its immediate left, as depicted in Illustration
Illustration 20: Expand Internet Sales ...
The expanded pane within the Aggregations tab displays settings and
characteristics relevant to the Internet Sales measure group. We can see that
there are 54 aggregations, and an estimated partition size of 32,265. We can
see further information about the partitions from the rightmost Partitions
Click the cell
in the Partitions column, to give it the focus and enable the ellipses (...)
button on its right, as shown in Illustration 21.
Illustration 21: Enabling the Ellipses (...) Button ...
Click the ellipses (...) button.
Aggregation Design dialog appears where we see the Internet Sales design
selected at the top, as depicted in Illustration 22.
Illustration 20: The Assign Aggregation Design Dialog
see the assignment of the aggregation designs to one or more destination partitions
(four partitions, in the present case). Between the name of each partition and
the name of the aggregation design assigned to it, we can see the source table
or query for the partition, as we can elsewhere.
Click OK to dismiss the Assign
Aggregation Design dialog, and to return to the Aggregations tab in the Cube
And so we
see the settings that exist within the measure group that we have examined
within the sample cube. Recall that every measure group is created with at
least one partition from the outset, and, that if we wish to plan partitions
before their creation, we need to keep in mind the settings that we can modify,
once we have accomplished this, with regard to aggregations. We typically
modify aggregations with the Aggregation Wizard, a hands-on introduction to which
we give in another article of this series.