Proactive Caching and Real-Time Updates - Microsoft SQL Server 2008 Analysis Services - page 436

NOTE
ROLAP aggregations are usually implemented as indexed views in a SQL Server rela-
tional database. (See Chapter 23, “Aggregation Design and Usage-Based Optimization,”
for more information.)

In some situations, you will want to schedule reprocessing of the MOLAP cache regardless
of whether a notification is received. In other words, you want to define how “stale” your
MOLAP cache can be. For that, you can use the ForceRebuildInterval property. In this
property, you can specify the length of time after the last cache was built that rebuilding
of a new cache can start. The default value -1 (infinite) means no periodic rebuild .

Proactive Caching Scenarios

Four proactive caching timing properties— SilenceInterval , SilenceOverrideInterval ,
ForceRebuildInterval , and Latency —can render your system useless when you use them
together without caution. Analysis Services provides a user interface that enables you to
choose from a number of scenarios that combine meaningful settings for proactive
caching properties.

You can find this user interface in SQL Server Management Studio and in Business
Intelligence Development Studio (BI Dev Studio). In SQL Server Management Studio, you
can access it through the Cube Properties, Partition Properties, and Dimension Properties
dialog boxes. BI Dev Studio provides access through the Partitions tab. Figure 24.4 shows
the user interface you will see if you right-click the Store dimension in SQL Server
Management Studio, select Properties from the resulting menu, and then select the
Proactive Caching page.

Slide the bar on this page to select a scenario with preset timing values. You can click the
Options button to see the values for the proactive caching in more detail.

MOLAP Scenario
The MOLAP scenario sets the storage mode for a partition or dimension to MOLAP. In this
scenario, proactive caching is disabled.

Scheduled MOLAP Scenario

The values for properties in this scenario are as follows:

. SilenceInterval = -1 (infinite)

. SilenceOverrideInterval = -1 (infinite)

. Latency = -1 (infinite)

. ForceRebuildInterval = 1 day