Databases Reference
In-Depth Information
because the Analysis Services's existing MOLAP cache is outdated and Ana-
lysis Services needs to fetch the results from the relational data source.
Latency simply refers to the amount of time you want the system to wait be-
fore unceremoniously dumping an existing MOLAP cache that is used to
serve users. The SilenceInterval indicates that no less than the specified peri-
od must elapse before initiating the rebuilding of a new MOLAP cache upon
data change. SilenceOverrideInterval is a little trickier to get your head
around, but by no means daunting. If SilenceInterval is reset time and again
due to frequent data changes then the MOLAP cache never gets rebuilt fully
and gets dumped often whenever data changes. There is some limit to our
patience since users will always see performance degradation from the time
Analysis Services switches to fetching the data from the relational data
source after the specified latency time. To overcome this issue SilenceOver-
ride Interval property ensures that it stops resetting the silence interval for fu-
ture data changes till the existing MOLAP cache is rebuilt fully.
Figure 18-13
Normally you know how frequently updates are occurring to your relational
data source. Based on that information you can specify the SilenceInterval.
On certain occasions there might be frequent data changes that result in the
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