This property is named DataMining\AllowSessionMiningModels
and it must be set to True, as the default value is False. In order to this, a database
or data warehousing administer would open SQL Server Management Studio and
connect to the server running Analysis Services. By right-clicking on the server and
choosing Properties, the administrator can access the server properties and change
the setting. Figure 5-27 shows both the location of the setting and the fact that it has
been set to true, although it has not yet been changed. Notice also in Figure 5-27 that
the Restart column does not have a Yes in it. This is good news; this means the server
does not have to be restarted when this value is changed.
Once the AllowSessionMiningModels property has been set to True, the Trend
Chart can be created and properly provide forecasts. To produce a forecast, there
must be at least three time periods on which to build the forecast, though more
values will produce better forecasts up to a point. You should realize, however, that
Figure 5-27 Setting the AllowSessionMiningModel property on the Analysis Services
instance in order to enable Trend Analysis Charts
C h a p t e r 5 : M o n i t o r i n g i n P e r f o r m a n c e P o i n t S e r v e r 121
sales data for a product that occurred ten years ago probably has little bearing on
sales today.
In order to create a Trend Chart, there must be a scorecard that contains the KPI
of interest. For this example there is a simple scorecard that shows the Gross Profit
Margin for the eight quarters covering 2002 and 2003.
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